diff options
Diffstat (limited to 'pkg/sentry/fsimpl')
37 files changed, 948 insertions, 146 deletions
diff --git a/pkg/sentry/fsimpl/ext/BUILD b/pkg/sentry/fsimpl/ext/BUILD index abc610ef3..7b1eec3da 100644 --- a/pkg/sentry/fsimpl/ext/BUILD +++ b/pkg/sentry/fsimpl/ext/BUILD @@ -51,6 +51,8 @@ go_library( "//pkg/fd", "//pkg/fspath", "//pkg/log", + "//pkg/marshal", + "//pkg/marshal/primitive", "//pkg/safemem", "//pkg/sentry/arch", "//pkg/sentry/fs", @@ -86,9 +88,9 @@ go_test( library = ":ext", deps = [ "//pkg/abi/linux", - "//pkg/binary", "//pkg/context", "//pkg/fspath", + "//pkg/marshal/primitive", "//pkg/sentry/contexttest", "//pkg/sentry/fsimpl/ext/disklayout", "//pkg/sentry/kernel/auth", diff --git a/pkg/sentry/fsimpl/ext/block_map_file.go b/pkg/sentry/fsimpl/ext/block_map_file.go index 8bb104ff0..1165234f9 100644 --- a/pkg/sentry/fsimpl/ext/block_map_file.go +++ b/pkg/sentry/fsimpl/ext/block_map_file.go @@ -18,7 +18,7 @@ import ( "io" "math" - "gvisor.dev/gvisor/pkg/binary" + "gvisor.dev/gvisor/pkg/marshal/primitive" "gvisor.dev/gvisor/pkg/syserror" ) @@ -34,19 +34,19 @@ type blockMapFile struct { // directBlks are the direct blocks numbers. The physical blocks pointed by // these holds file data. Contains file blocks 0 to 11. - directBlks [numDirectBlks]uint32 + directBlks [numDirectBlks]primitive.Uint32 // indirectBlk is the physical block which contains (blkSize/4) direct block // numbers (as uint32 integers). - indirectBlk uint32 + indirectBlk primitive.Uint32 // doubleIndirectBlk is the physical block which contains (blkSize/4) indirect // block numbers (as uint32 integers). - doubleIndirectBlk uint32 + doubleIndirectBlk primitive.Uint32 // tripleIndirectBlk is the physical block which contains (blkSize/4) doubly // indirect block numbers (as uint32 integers). - tripleIndirectBlk uint32 + tripleIndirectBlk primitive.Uint32 // coverage at (i)th index indicates the amount of file data a node at // height (i) covers. Height 0 is the direct block. @@ -68,10 +68,12 @@ func newBlockMapFile(args inodeArgs) (*blockMapFile, error) { } blkMap := file.regFile.inode.diskInode.Data() - binary.Unmarshal(blkMap[:numDirectBlks*4], binary.LittleEndian, &file.directBlks) - binary.Unmarshal(blkMap[numDirectBlks*4:(numDirectBlks+1)*4], binary.LittleEndian, &file.indirectBlk) - binary.Unmarshal(blkMap[(numDirectBlks+1)*4:(numDirectBlks+2)*4], binary.LittleEndian, &file.doubleIndirectBlk) - binary.Unmarshal(blkMap[(numDirectBlks+2)*4:(numDirectBlks+3)*4], binary.LittleEndian, &file.tripleIndirectBlk) + for i := 0; i < numDirectBlks; i++ { + file.directBlks[i].UnmarshalBytes(blkMap[i*4 : (i+1)*4]) + } + file.indirectBlk.UnmarshalBytes(blkMap[numDirectBlks*4 : (numDirectBlks+1)*4]) + file.doubleIndirectBlk.UnmarshalBytes(blkMap[(numDirectBlks+1)*4 : (numDirectBlks+2)*4]) + file.tripleIndirectBlk.UnmarshalBytes(blkMap[(numDirectBlks+2)*4 : (numDirectBlks+3)*4]) return file, nil } @@ -117,16 +119,16 @@ func (f *blockMapFile) ReadAt(dst []byte, off int64) (int, error) { switch { case offset < dirBlksEnd: // Direct block. - curR, err = f.read(f.directBlks[offset/f.regFile.inode.blkSize], offset%f.regFile.inode.blkSize, 0, dst[read:]) + curR, err = f.read(uint32(f.directBlks[offset/f.regFile.inode.blkSize]), offset%f.regFile.inode.blkSize, 0, dst[read:]) case offset < indirBlkEnd: // Indirect block. - curR, err = f.read(f.indirectBlk, offset-dirBlksEnd, 1, dst[read:]) + curR, err = f.read(uint32(f.indirectBlk), offset-dirBlksEnd, 1, dst[read:]) case offset < doubIndirBlkEnd: // Doubly indirect block. - curR, err = f.read(f.doubleIndirectBlk, offset-indirBlkEnd, 2, dst[read:]) + curR, err = f.read(uint32(f.doubleIndirectBlk), offset-indirBlkEnd, 2, dst[read:]) default: // Triply indirect block. - curR, err = f.read(f.tripleIndirectBlk, offset-doubIndirBlkEnd, 3, dst[read:]) + curR, err = f.read(uint32(f.tripleIndirectBlk), offset-doubIndirBlkEnd, 3, dst[read:]) } read += curR @@ -174,13 +176,13 @@ func (f *blockMapFile) read(curPhyBlk uint32, relFileOff uint64, height uint, ds read := 0 curChildOff := relFileOff % childCov for i := startIdx; i < endIdx; i++ { - var childPhyBlk uint32 + var childPhyBlk primitive.Uint32 err := readFromDisk(f.regFile.inode.fs.dev, curPhyBlkOff+int64(i*4), &childPhyBlk) if err != nil { return read, err } - n, err := f.read(childPhyBlk, curChildOff, height-1, dst[read:]) + n, err := f.read(uint32(childPhyBlk), curChildOff, height-1, dst[read:]) read += n if err != nil { return read, err diff --git a/pkg/sentry/fsimpl/ext/block_map_test.go b/pkg/sentry/fsimpl/ext/block_map_test.go index 6fa84e7aa..ed98b482e 100644 --- a/pkg/sentry/fsimpl/ext/block_map_test.go +++ b/pkg/sentry/fsimpl/ext/block_map_test.go @@ -20,7 +20,7 @@ import ( "testing" "github.com/google/go-cmp/cmp" - "gvisor.dev/gvisor/pkg/binary" + "gvisor.dev/gvisor/pkg/marshal/primitive" "gvisor.dev/gvisor/pkg/sentry/fsimpl/ext/disklayout" ) @@ -87,29 +87,33 @@ func blockMapSetUp(t *testing.T) (*blockMapFile, []byte) { mockDisk := make([]byte, mockBMDiskSize) var fileData []byte blkNums := newBlkNumGen() - var data []byte + off := 0 + data := make([]byte, (numDirectBlks+3)*(*primitive.Uint32)(nil).SizeBytes()) // Write the direct blocks. for i := 0; i < numDirectBlks; i++ { - curBlkNum := blkNums.next() - data = binary.Marshal(data, binary.LittleEndian, curBlkNum) - fileData = append(fileData, writeFileDataToBlock(mockDisk, curBlkNum, 0, blkNums)...) + curBlkNum := primitive.Uint32(blkNums.next()) + curBlkNum.MarshalBytes(data[off:]) + off += curBlkNum.SizeBytes() + fileData = append(fileData, writeFileDataToBlock(mockDisk, uint32(curBlkNum), 0, blkNums)...) } // Write to indirect block. - indirectBlk := blkNums.next() - data = binary.Marshal(data, binary.LittleEndian, indirectBlk) - fileData = append(fileData, writeFileDataToBlock(mockDisk, indirectBlk, 1, blkNums)...) - - // Write to indirect block. - doublyIndirectBlk := blkNums.next() - data = binary.Marshal(data, binary.LittleEndian, doublyIndirectBlk) - fileData = append(fileData, writeFileDataToBlock(mockDisk, doublyIndirectBlk, 2, blkNums)...) - - // Write to indirect block. - triplyIndirectBlk := blkNums.next() - data = binary.Marshal(data, binary.LittleEndian, triplyIndirectBlk) - fileData = append(fileData, writeFileDataToBlock(mockDisk, triplyIndirectBlk, 3, blkNums)...) + indirectBlk := primitive.Uint32(blkNums.next()) + indirectBlk.MarshalBytes(data[off:]) + off += indirectBlk.SizeBytes() + fileData = append(fileData, writeFileDataToBlock(mockDisk, uint32(indirectBlk), 1, blkNums)...) + + // Write to double indirect block. + doublyIndirectBlk := primitive.Uint32(blkNums.next()) + doublyIndirectBlk.MarshalBytes(data[off:]) + off += doublyIndirectBlk.SizeBytes() + fileData = append(fileData, writeFileDataToBlock(mockDisk, uint32(doublyIndirectBlk), 2, blkNums)...) + + // Write to triple indirect block. + triplyIndirectBlk := primitive.Uint32(blkNums.next()) + triplyIndirectBlk.MarshalBytes(data[off:]) + fileData = append(fileData, writeFileDataToBlock(mockDisk, uint32(triplyIndirectBlk), 3, blkNums)...) args := inodeArgs{ fs: &filesystem{ @@ -142,9 +146,9 @@ func writeFileDataToBlock(disk []byte, blkNum uint32, height uint, blkNums *blkN var fileData []byte for off := blkNum * mockBMBlkSize; off < (blkNum+1)*mockBMBlkSize; off += 4 { - curBlkNum := blkNums.next() - copy(disk[off:off+4], binary.Marshal(nil, binary.LittleEndian, curBlkNum)) - fileData = append(fileData, writeFileDataToBlock(disk, curBlkNum, height-1, blkNums)...) + curBlkNum := primitive.Uint32(blkNums.next()) + curBlkNum.MarshalBytes(disk[off : off+4]) + fileData = append(fileData, writeFileDataToBlock(disk, uint32(curBlkNum), height-1, blkNums)...) } return fileData } diff --git a/pkg/sentry/fsimpl/ext/directory.go b/pkg/sentry/fsimpl/ext/directory.go index 452450d82..0ad79b381 100644 --- a/pkg/sentry/fsimpl/ext/directory.go +++ b/pkg/sentry/fsimpl/ext/directory.go @@ -16,7 +16,6 @@ package ext import ( "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/fs" @@ -100,7 +99,7 @@ func newDirectory(args inodeArgs, newDirent bool) (*directory, error) { } else { curDirent.diskDirent = &disklayout.DirentOld{} } - binary.Unmarshal(buf, binary.LittleEndian, curDirent.diskDirent) + curDirent.diskDirent.UnmarshalBytes(buf) if curDirent.diskDirent.Inode() != 0 && len(curDirent.diskDirent.FileName()) != 0 { // Inode number and name length fields being set to 0 is used to indicate diff --git a/pkg/sentry/fsimpl/ext/disklayout/BUILD b/pkg/sentry/fsimpl/ext/disklayout/BUILD index 9bd9c76c0..d98a05dd8 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/BUILD +++ b/pkg/sentry/fsimpl/ext/disklayout/BUILD @@ -22,10 +22,11 @@ go_library( "superblock_old.go", "test_utils.go", ], + marshal = True, visibility = ["//pkg/sentry:internal"], deps = [ "//pkg/abi/linux", - "//pkg/binary", + "//pkg/marshal", "//pkg/sentry/fs", "//pkg/sentry/kernel/auth", "//pkg/sentry/kernel/time", diff --git a/pkg/sentry/fsimpl/ext/disklayout/block_group.go b/pkg/sentry/fsimpl/ext/disklayout/block_group.go index ad6f4fef8..0d56ae9da 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/block_group.go +++ b/pkg/sentry/fsimpl/ext/disklayout/block_group.go @@ -14,6 +14,10 @@ package disklayout +import ( + "gvisor.dev/gvisor/pkg/marshal" +) + // BlockGroup represents a Linux ext block group descriptor. An ext file system // is split into a series of block groups. This provides an access layer to // information needed to access and use a block group. @@ -30,6 +34,8 @@ package disklayout // // See https://www.kernel.org/doc/html/latest/filesystems/ext4/globals.html#block-group-descriptors. type BlockGroup interface { + marshal.Marshallable + // InodeTable returns the absolute block number of the block containing the // inode table. This points to an array of Inode structs. Inode tables are // statically allocated at mkfs time. The superblock records the number of diff --git a/pkg/sentry/fsimpl/ext/disklayout/block_group_32.go b/pkg/sentry/fsimpl/ext/disklayout/block_group_32.go index 3e16c76db..a35fa22a0 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/block_group_32.go +++ b/pkg/sentry/fsimpl/ext/disklayout/block_group_32.go @@ -17,6 +17,8 @@ package disklayout // BlockGroup32Bit emulates the first half of struct ext4_group_desc in // fs/ext4/ext4.h. It is the block group descriptor struct for ext2, ext3 and // 32-bit ext4 filesystems. It implements BlockGroup interface. +// +// +marshal type BlockGroup32Bit struct { BlockBitmapLo uint32 InodeBitmapLo uint32 diff --git a/pkg/sentry/fsimpl/ext/disklayout/block_group_64.go b/pkg/sentry/fsimpl/ext/disklayout/block_group_64.go index 9a809197a..d54d1d345 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/block_group_64.go +++ b/pkg/sentry/fsimpl/ext/disklayout/block_group_64.go @@ -18,6 +18,8 @@ package disklayout // It is the block group descriptor struct for 64-bit ext4 filesystems. // It implements BlockGroup interface. It is an extension of the 32-bit // version of BlockGroup. +// +// +marshal type BlockGroup64Bit struct { // We embed the 32-bit struct here because 64-bit version is just an extension // of the 32-bit version. diff --git a/pkg/sentry/fsimpl/ext/disklayout/block_group_test.go b/pkg/sentry/fsimpl/ext/disklayout/block_group_test.go index 0ef4294c0..e4ce484e4 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/block_group_test.go +++ b/pkg/sentry/fsimpl/ext/disklayout/block_group_test.go @@ -21,6 +21,8 @@ import ( // TestBlockGroupSize tests that the block group descriptor structs are of the // correct size. func TestBlockGroupSize(t *testing.T) { - assertSize(t, BlockGroup32Bit{}, 32) - assertSize(t, BlockGroup64Bit{}, 64) + var bgSmall BlockGroup32Bit + assertSize(t, &bgSmall, 32) + var bgBig BlockGroup64Bit + assertSize(t, &bgBig, 64) } diff --git a/pkg/sentry/fsimpl/ext/disklayout/dirent.go b/pkg/sentry/fsimpl/ext/disklayout/dirent.go index 417b6cf65..568c8cb4c 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/dirent.go +++ b/pkg/sentry/fsimpl/ext/disklayout/dirent.go @@ -15,6 +15,7 @@ package disklayout import ( + "gvisor.dev/gvisor/pkg/marshal" "gvisor.dev/gvisor/pkg/sentry/fs" ) @@ -51,6 +52,8 @@ var ( // // See https://www.kernel.org/doc/html/latest/filesystems/ext4/dynamic.html#linear-classic-directories. type Dirent interface { + marshal.Marshallable + // Inode returns the absolute inode number of the underlying inode. // Inode number 0 signifies an unused dirent. Inode() uint32 diff --git a/pkg/sentry/fsimpl/ext/disklayout/dirent_new.go b/pkg/sentry/fsimpl/ext/disklayout/dirent_new.go index 29ae4a5c2..51f9c2946 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/dirent_new.go +++ b/pkg/sentry/fsimpl/ext/disklayout/dirent_new.go @@ -29,12 +29,14 @@ import ( // Note: This struct can be of variable size on disk. The one described below // is of maximum size and the FileName beyond NameLength bytes might contain // garbage. +// +// +marshal type DirentNew struct { InodeNumber uint32 RecordLength uint16 NameLength uint8 FileTypeRaw uint8 - FileNameRaw [MaxFileName]byte + FileNameRaw [MaxFileName]byte `marshal:"unaligned"` } // Compiles only if DirentNew implements Dirent. diff --git a/pkg/sentry/fsimpl/ext/disklayout/dirent_old.go b/pkg/sentry/fsimpl/ext/disklayout/dirent_old.go index 6fff12a6e..d4b19e086 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/dirent_old.go +++ b/pkg/sentry/fsimpl/ext/disklayout/dirent_old.go @@ -22,11 +22,13 @@ import "gvisor.dev/gvisor/pkg/sentry/fs" // Note: This struct can be of variable size on disk. The one described below // is of maximum size and the FileName beyond NameLength bytes might contain // garbage. +// +// +marshal type DirentOld struct { InodeNumber uint32 RecordLength uint16 NameLength uint16 - FileNameRaw [MaxFileName]byte + FileNameRaw [MaxFileName]byte `marshal:"unaligned"` } // Compiles only if DirentOld implements Dirent. diff --git a/pkg/sentry/fsimpl/ext/disklayout/dirent_test.go b/pkg/sentry/fsimpl/ext/disklayout/dirent_test.go index 934919f8a..3486864dc 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/dirent_test.go +++ b/pkg/sentry/fsimpl/ext/disklayout/dirent_test.go @@ -21,6 +21,8 @@ import ( // TestDirentSize tests that the dirent structs are of the correct // size. func TestDirentSize(t *testing.T) { - assertSize(t, DirentOld{}, uintptr(DirentSize)) - assertSize(t, DirentNew{}, uintptr(DirentSize)) + var dOld DirentOld + assertSize(t, &dOld, DirentSize) + var dNew DirentNew + assertSize(t, &dNew, DirentSize) } diff --git a/pkg/sentry/fsimpl/ext/disklayout/disklayout.go b/pkg/sentry/fsimpl/ext/disklayout/disklayout.go index bdf4e2132..0834e9ba8 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/disklayout.go +++ b/pkg/sentry/fsimpl/ext/disklayout/disklayout.go @@ -36,8 +36,6 @@ // escape analysis on an unknown implementation at compile time. // // Notes: -// - All fields in these structs are exported because binary.Read would -// panic otherwise. // - All structures on disk are in little-endian order. Only jbd2 (journal) // structures are in big-endian order. // - All OS dependent fields in these structures will be interpretted using diff --git a/pkg/sentry/fsimpl/ext/disklayout/extent.go b/pkg/sentry/fsimpl/ext/disklayout/extent.go index 4110649ab..b13999bfc 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/extent.go +++ b/pkg/sentry/fsimpl/ext/disklayout/extent.go @@ -14,6 +14,10 @@ package disklayout +import ( + "gvisor.dev/gvisor/pkg/marshal" +) + // Extents were introduced in ext4 and provide huge performance gains in terms // data locality and reduced metadata block usage. Extents are organized in // extent trees. The root node is contained in inode.BlocksRaw. @@ -64,6 +68,8 @@ type ExtentNode struct { // ExtentEntry represents an extent tree node entry. The entry can either be // an ExtentIdx or Extent itself. This exists to simplify navigation logic. type ExtentEntry interface { + marshal.Marshallable + // FileBlock returns the first file block number covered by this entry. FileBlock() uint32 @@ -75,6 +81,8 @@ type ExtentEntry interface { // tree node begins with this and is followed by `NumEntries` number of: // - Extent if `Depth` == 0 // - ExtentIdx otherwise +// +// +marshal type ExtentHeader struct { // Magic in the extent magic number, must be 0xf30a. Magic uint16 @@ -96,6 +104,8 @@ type ExtentHeader struct { // internal nodes. Sorted in ascending order based on FirstFileBlock since // Linux does a binary search on this. This points to a block containing the // child node. +// +// +marshal type ExtentIdx struct { FirstFileBlock uint32 ChildBlockLo uint32 @@ -121,6 +131,8 @@ func (ei *ExtentIdx) PhysicalBlock() uint64 { // nodes. Sorted in ascending order based on FirstFileBlock since Linux does a // binary search on this. This points to an array of data blocks containing the // file data. It covers `Length` data blocks starting from `StartBlock`. +// +// +marshal type Extent struct { FirstFileBlock uint32 Length uint16 diff --git a/pkg/sentry/fsimpl/ext/disklayout/extent_test.go b/pkg/sentry/fsimpl/ext/disklayout/extent_test.go index 8762b90db..c96002e19 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/extent_test.go +++ b/pkg/sentry/fsimpl/ext/disklayout/extent_test.go @@ -21,7 +21,10 @@ import ( // TestExtentSize tests that the extent structs are of the correct // size. func TestExtentSize(t *testing.T) { - assertSize(t, ExtentHeader{}, ExtentHeaderSize) - assertSize(t, ExtentIdx{}, ExtentEntrySize) - assertSize(t, Extent{}, ExtentEntrySize) + var h ExtentHeader + assertSize(t, &h, ExtentHeaderSize) + var i ExtentIdx + assertSize(t, &i, ExtentEntrySize) + var e Extent + assertSize(t, &e, ExtentEntrySize) } diff --git a/pkg/sentry/fsimpl/ext/disklayout/inode.go b/pkg/sentry/fsimpl/ext/disklayout/inode.go index 88ae913f5..ef25040a9 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/inode.go +++ b/pkg/sentry/fsimpl/ext/disklayout/inode.go @@ -16,6 +16,7 @@ package disklayout import ( "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/marshal" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/kernel/time" ) @@ -38,6 +39,8 @@ const ( // // See https://www.kernel.org/doc/html/latest/filesystems/ext4/dynamic.html#index-nodes. type Inode interface { + marshal.Marshallable + // Mode returns the linux file mode which is majorly used to extract // information like: // - File permissions (read/write/execute by user/group/others). diff --git a/pkg/sentry/fsimpl/ext/disklayout/inode_new.go b/pkg/sentry/fsimpl/ext/disklayout/inode_new.go index 8f9f574ce..a4503f5cf 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/inode_new.go +++ b/pkg/sentry/fsimpl/ext/disklayout/inode_new.go @@ -27,6 +27,8 @@ import "gvisor.dev/gvisor/pkg/sentry/kernel/time" // are used to provide nanoscond precision. Hence, these timestamps will now // overflow in May 2446. // See https://www.kernel.org/doc/html/latest/filesystems/ext4/dynamic.html#inode-timestamps. +// +// +marshal type InodeNew struct { InodeOld diff --git a/pkg/sentry/fsimpl/ext/disklayout/inode_old.go b/pkg/sentry/fsimpl/ext/disklayout/inode_old.go index db25b11b6..e6b28babf 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/inode_old.go +++ b/pkg/sentry/fsimpl/ext/disklayout/inode_old.go @@ -30,6 +30,8 @@ const ( // // All fields representing time are in seconds since the epoch. Which means that // they will overflow in January 2038. +// +// +marshal type InodeOld struct { ModeRaw uint16 UIDLo uint16 diff --git a/pkg/sentry/fsimpl/ext/disklayout/inode_test.go b/pkg/sentry/fsimpl/ext/disklayout/inode_test.go index dd03ee50e..90744e956 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/inode_test.go +++ b/pkg/sentry/fsimpl/ext/disklayout/inode_test.go @@ -24,10 +24,12 @@ import ( // TestInodeSize tests that the inode structs are of the correct size. func TestInodeSize(t *testing.T) { - assertSize(t, InodeOld{}, OldInodeSize) + var iOld InodeOld + assertSize(t, &iOld, OldInodeSize) // This was updated from 156 bytes to 160 bytes in Oct 2015. - assertSize(t, InodeNew{}, 160) + var iNew InodeNew + assertSize(t, &iNew, 160) } // TestTimestampSeconds tests that the seconds part of [a/c/m] timestamps in diff --git a/pkg/sentry/fsimpl/ext/disklayout/superblock.go b/pkg/sentry/fsimpl/ext/disklayout/superblock.go index 8bb327006..70948ebe9 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/superblock.go +++ b/pkg/sentry/fsimpl/ext/disklayout/superblock.go @@ -14,6 +14,10 @@ package disklayout +import ( + "gvisor.dev/gvisor/pkg/marshal" +) + const ( // SbOffset is the absolute offset at which the superblock is placed. SbOffset = 1024 @@ -38,6 +42,8 @@ const ( // // See https://www.kernel.org/doc/html/latest/filesystems/ext4/globals.html#super-block. type SuperBlock interface { + marshal.Marshallable + // InodesCount returns the total number of inodes in this filesystem. InodesCount() uint32 diff --git a/pkg/sentry/fsimpl/ext/disklayout/superblock_32.go b/pkg/sentry/fsimpl/ext/disklayout/superblock_32.go index 53e515fd3..4dc6080fb 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/superblock_32.go +++ b/pkg/sentry/fsimpl/ext/disklayout/superblock_32.go @@ -17,6 +17,8 @@ package disklayout // SuperBlock32Bit implements SuperBlock and represents the 32-bit version of // the ext4_super_block struct in fs/ext4/ext4.h. Should be used only if // RevLevel = DynamicRev and 64-bit feature is disabled. +// +// +marshal type SuperBlock32Bit struct { // We embed the old superblock struct here because the 32-bit version is just // an extension of the old version. diff --git a/pkg/sentry/fsimpl/ext/disklayout/superblock_64.go b/pkg/sentry/fsimpl/ext/disklayout/superblock_64.go index 7c1053fb4..2c9039327 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/superblock_64.go +++ b/pkg/sentry/fsimpl/ext/disklayout/superblock_64.go @@ -19,6 +19,8 @@ package disklayout // 1024 bytes (smallest possible block size) and hence the superblock always // fits in no more than one data block. Should only be used when the 64-bit // feature is set. +// +// +marshal type SuperBlock64Bit struct { // We embed the 32-bit struct here because 64-bit version is just an extension // of the 32-bit version. diff --git a/pkg/sentry/fsimpl/ext/disklayout/superblock_old.go b/pkg/sentry/fsimpl/ext/disklayout/superblock_old.go index 9221e0251..e4709f23c 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/superblock_old.go +++ b/pkg/sentry/fsimpl/ext/disklayout/superblock_old.go @@ -16,6 +16,8 @@ package disklayout // SuperBlockOld implements SuperBlock and represents the old version of the // superblock struct. Should be used only if RevLevel = OldRev. +// +// +marshal type SuperBlockOld struct { InodesCountRaw uint32 BlocksCountLo uint32 diff --git a/pkg/sentry/fsimpl/ext/disklayout/superblock_test.go b/pkg/sentry/fsimpl/ext/disklayout/superblock_test.go index 463b5ba21..b734b6987 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/superblock_test.go +++ b/pkg/sentry/fsimpl/ext/disklayout/superblock_test.go @@ -21,7 +21,10 @@ import ( // TestSuperBlockSize tests that the superblock structs are of the correct // size. func TestSuperBlockSize(t *testing.T) { - assertSize(t, SuperBlockOld{}, 84) - assertSize(t, SuperBlock32Bit{}, 336) - assertSize(t, SuperBlock64Bit{}, 1024) + var sbOld SuperBlockOld + assertSize(t, &sbOld, 84) + var sb32 SuperBlock32Bit + assertSize(t, &sb32, 336) + var sb64 SuperBlock64Bit + assertSize(t, &sb64, 1024) } diff --git a/pkg/sentry/fsimpl/ext/disklayout/test_utils.go b/pkg/sentry/fsimpl/ext/disklayout/test_utils.go index 9c63f04c0..a4bc08411 100644 --- a/pkg/sentry/fsimpl/ext/disklayout/test_utils.go +++ b/pkg/sentry/fsimpl/ext/disklayout/test_utils.go @@ -18,13 +18,13 @@ import ( "reflect" "testing" - "gvisor.dev/gvisor/pkg/binary" + "gvisor.dev/gvisor/pkg/marshal" ) -func assertSize(t *testing.T, v interface{}, want uintptr) { +func assertSize(t *testing.T, v marshal.Marshallable, want int) { t.Helper() - if got := binary.Size(v); got != want { + if got := v.SizeBytes(); got != want { t.Errorf("struct %s should be exactly %d bytes but is %d bytes", reflect.TypeOf(v).Name(), want, got) } } diff --git a/pkg/sentry/fsimpl/ext/extent_file.go b/pkg/sentry/fsimpl/ext/extent_file.go index 04917d762..778460107 100644 --- a/pkg/sentry/fsimpl/ext/extent_file.go +++ b/pkg/sentry/fsimpl/ext/extent_file.go @@ -18,7 +18,6 @@ import ( "io" "sort" - "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/sentry/fsimpl/ext/disklayout" "gvisor.dev/gvisor/pkg/syserror" ) @@ -60,7 +59,7 @@ func newExtentFile(args inodeArgs) (*extentFile, error) { func (f *extentFile) buildExtTree() error { rootNodeData := f.regFile.inode.diskInode.Data() - binary.Unmarshal(rootNodeData[:disklayout.ExtentHeaderSize], binary.LittleEndian, &f.root.Header) + f.root.Header.UnmarshalBytes(rootNodeData[:disklayout.ExtentHeaderSize]) // Root node can not have more than 4 entries: 60 bytes = 1 header + 4 entries. if f.root.Header.NumEntries > 4 { @@ -79,7 +78,7 @@ func (f *extentFile) buildExtTree() error { // Internal node. curEntry = &disklayout.ExtentIdx{} } - binary.Unmarshal(rootNodeData[off:off+disklayout.ExtentEntrySize], binary.LittleEndian, curEntry) + curEntry.UnmarshalBytes(rootNodeData[off : off+disklayout.ExtentEntrySize]) f.root.Entries[i].Entry = curEntry } diff --git a/pkg/sentry/fsimpl/ext/extent_test.go b/pkg/sentry/fsimpl/ext/extent_test.go index cd10d46ee..985f76ac0 100644 --- a/pkg/sentry/fsimpl/ext/extent_test.go +++ b/pkg/sentry/fsimpl/ext/extent_test.go @@ -21,7 +21,6 @@ import ( "github.com/google/go-cmp/cmp" "github.com/google/go-cmp/cmp/cmpopts" - "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/sentry/fsimpl/ext/disklayout" ) @@ -202,13 +201,14 @@ func extentTreeSetUp(t *testing.T, root *disklayout.ExtentNode) (*extentFile, [] // writeTree writes the tree represented by `root` to the inode and disk. It // also writes random file data on disk. func writeTree(in *inode, disk []byte, root *disklayout.ExtentNode, mockExtentBlkSize uint64) []byte { - rootData := binary.Marshal(nil, binary.LittleEndian, root.Header) + rootData := in.diskInode.Data() + root.Header.MarshalBytes(rootData) + off := root.Header.SizeBytes() for _, ep := range root.Entries { - rootData = binary.Marshal(rootData, binary.LittleEndian, ep.Entry) + ep.Entry.MarshalBytes(rootData[off:]) + off += ep.Entry.SizeBytes() } - copy(in.diskInode.Data(), rootData) - var fileData []byte for _, ep := range root.Entries { if root.Header.Height == 0 { @@ -223,13 +223,14 @@ func writeTree(in *inode, disk []byte, root *disklayout.ExtentNode, mockExtentBl // writeTreeToDisk is the recursive step for writeTree which writes the tree // on the disk only. Also writes random file data on disk. func writeTreeToDisk(disk []byte, curNode disklayout.ExtentEntryPair) []byte { - nodeData := binary.Marshal(nil, binary.LittleEndian, curNode.Node.Header) + nodeData := disk[curNode.Entry.PhysicalBlock()*mockExtentBlkSize:] + curNode.Node.Header.MarshalBytes(nodeData) + off := curNode.Node.Header.SizeBytes() for _, ep := range curNode.Node.Entries { - nodeData = binary.Marshal(nodeData, binary.LittleEndian, ep.Entry) + ep.Entry.MarshalBytes(nodeData[off:]) + off += ep.Entry.SizeBytes() } - copy(disk[curNode.Entry.PhysicalBlock()*mockExtentBlkSize:], nodeData) - var fileData []byte for _, ep := range curNode.Node.Entries { if curNode.Node.Header.Height == 0 { diff --git a/pkg/sentry/fsimpl/ext/utils.go b/pkg/sentry/fsimpl/ext/utils.go index d8b728f8c..58ef7b9b8 100644 --- a/pkg/sentry/fsimpl/ext/utils.go +++ b/pkg/sentry/fsimpl/ext/utils.go @@ -17,21 +17,21 @@ package ext import ( "io" - "gvisor.dev/gvisor/pkg/binary" + "gvisor.dev/gvisor/pkg/marshal" "gvisor.dev/gvisor/pkg/sentry/fsimpl/ext/disklayout" "gvisor.dev/gvisor/pkg/syserror" ) // readFromDisk performs a binary read from disk into the given struct from // the absolute offset provided. -func readFromDisk(dev io.ReaderAt, abOff int64, v interface{}) error { - n := binary.Size(v) +func readFromDisk(dev io.ReaderAt, abOff int64, v marshal.Marshallable) error { + n := v.SizeBytes() buf := make([]byte, n) if read, _ := dev.ReadAt(buf, abOff); read < int(n) { return syserror.EIO } - binary.Unmarshal(buf, binary.LittleEndian, v) + v.UnmarshalBytes(buf) return nil } diff --git a/pkg/sentry/fsimpl/host/socket.go b/pkg/sentry/fsimpl/host/socket.go index 131145b85..8a447e29f 100644 --- a/pkg/sentry/fsimpl/host/socket.go +++ b/pkg/sentry/fsimpl/host/socket.go @@ -348,10 +348,10 @@ func (e *SCMConnectedEndpoint) Init() error { func (e *SCMConnectedEndpoint) Release(ctx context.Context) { e.DecRef(func() { e.mu.Lock() + fdnotifier.RemoveFD(int32(e.fd)) if err := syscall.Close(e.fd); err != nil { log.Warningf("Failed to close host fd %d: %v", err) } - fdnotifier.RemoveFD(int32(e.fd)) e.destroyLocked() e.mu.Unlock() }) diff --git a/pkg/sentry/fsimpl/signalfd/BUILD b/pkg/sentry/fsimpl/signalfd/BUILD index 067c1657f..adb610213 100644 --- a/pkg/sentry/fsimpl/signalfd/BUILD +++ b/pkg/sentry/fsimpl/signalfd/BUILD @@ -8,7 +8,6 @@ go_library( visibility = ["//pkg/sentry:internal"], deps = [ "//pkg/abi/linux", - "//pkg/binary", "//pkg/context", "//pkg/sentry/kernel", "//pkg/sentry/vfs", diff --git a/pkg/sentry/fsimpl/signalfd/signalfd.go b/pkg/sentry/fsimpl/signalfd/signalfd.go index bf11b425a..10f1452ef 100644 --- a/pkg/sentry/fsimpl/signalfd/signalfd.go +++ b/pkg/sentry/fsimpl/signalfd/signalfd.go @@ -16,7 +16,6 @@ package signalfd import ( "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/vfs" @@ -95,8 +94,7 @@ func (sfd *SignalFileDescription) Read(ctx context.Context, dst usermem.IOSequen } // Copy out the signal info using the specified format. - var buf [128]byte - binary.Marshal(buf[:0], usermem.ByteOrder, &linux.SignalfdSiginfo{ + infoNative := linux.SignalfdSiginfo{ Signo: uint32(info.Signo), Errno: info.Errno, Code: info.Code, @@ -105,9 +103,13 @@ func (sfd *SignalFileDescription) Read(ctx context.Context, dst usermem.IOSequen Status: info.Status(), Overrun: uint32(info.Overrun()), Addr: info.Addr(), - }) - n, err := dst.CopyOut(ctx, buf[:]) - return int64(n), err + } + n, err := infoNative.WriteTo(dst.Writer(ctx)) + if err == usermem.ErrEndOfIOSequence { + // Partial copy-out ok. + err = nil + } + return n, err } // Readiness implements waiter.Waitable.Readiness. diff --git a/pkg/sentry/fsimpl/sys/kcov.go b/pkg/sentry/fsimpl/sys/kcov.go index b75d70ae6..1a6749e53 100644 --- a/pkg/sentry/fsimpl/sys/kcov.go +++ b/pkg/sentry/fsimpl/sys/kcov.go @@ -104,7 +104,7 @@ func (fd *kcovFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) erro func (fd *kcovFD) Release(ctx context.Context) { // kcov instances have reference counts in Linux, but this seems sufficient // for our purposes. - fd.kcov.Reset() + fd.kcov.Clear() } // SetStat implements vfs.FileDescriptionImpl.SetStat. diff --git a/pkg/sentry/fsimpl/verity/BUILD b/pkg/sentry/fsimpl/verity/BUILD index bc8e38431..0ca750281 100644 --- a/pkg/sentry/fsimpl/verity/BUILD +++ b/pkg/sentry/fsimpl/verity/BUILD @@ -1,4 +1,4 @@ -load("//tools:defs.bzl", "go_library") +load("//tools:defs.bzl", "go_library", "go_test") licenses(["notice"]) @@ -26,3 +26,22 @@ go_library( "//pkg/usermem", ], ) + +go_test( + name = "verity_test", + srcs = [ + "verity_test.go", + ], + library = ":verity", + deps = [ + "//pkg/abi/linux", + "//pkg/context", + "//pkg/fspath", + "//pkg/sentry/arch", + "//pkg/sentry/fsimpl/tmpfs", + "//pkg/sentry/kernel/auth", + "//pkg/sentry/kernel/contexttest", + "//pkg/sentry/vfs", + "//pkg/usermem", + ], +) diff --git a/pkg/sentry/fsimpl/verity/filesystem.go b/pkg/sentry/fsimpl/verity/filesystem.go index 26b117ca4..7779271a9 100644 --- a/pkg/sentry/fsimpl/verity/filesystem.go +++ b/pkg/sentry/fsimpl/verity/filesystem.go @@ -20,6 +20,7 @@ import ( "io" "strconv" "strings" + "sync/atomic" "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" @@ -251,11 +252,35 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de Ctx: ctx, } + parentStat, err := vfsObj.StatAt(ctx, fs.creds, &vfs.PathOperation{ + Root: parent.lowerVD, + Start: parent.lowerVD, + }, &vfs.StatOptions{}) + if err == syserror.ENOENT { + return nil, alertIntegrityViolation(err, fmt.Sprintf("Failed to get parent stat for %s: %v", childPath, err)) + } + if err != nil { + return nil, err + } + // Since we are verifying against a directory Merkle tree, buf should // contain the root hash of the children in the parent Merkle tree when // Verify returns with success. var buf bytes.Buffer - if _, err := merkletree.Verify(&buf, &fdReader, &fdReader, int64(parentSize), int64(offset), int64(merkletree.DigestSize()), parent.rootHash, true /* dataAndTreeInSameFile */); err != nil && err != io.EOF { + if _, err := merkletree.Verify(&merkletree.VerifyParams{ + Out: &buf, + File: &fdReader, + Tree: &fdReader, + Size: int64(parentSize), + Name: parent.name, + Mode: uint32(parentStat.Mode), + UID: parentStat.UID, + GID: parentStat.GID, + ReadOffset: int64(offset), + ReadSize: int64(merkletree.DigestSize()), + ExpectedRoot: parent.rootHash, + DataAndTreeInSameFile: true, + }); err != nil && err != io.EOF { return nil, alertIntegrityViolation(syserror.EIO, fmt.Sprintf("Verification for %s failed: %v", childPath, err)) } @@ -266,6 +291,84 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de return child, nil } +// verifyStat verifies the stat against the verified root hash. The mode/uid/gid +// of the file is cached after verified. +func (fs *filesystem) verifyStat(ctx context.Context, d *dentry, stat linux.Statx) error { + vfsObj := fs.vfsfs.VirtualFilesystem() + + // Get the path to the child dentry. This is only used to provide path + // information in failure case. + childPath, err := vfsObj.PathnameWithDeleted(ctx, d.fs.rootDentry.lowerVD, d.lowerVD) + if err != nil { + return err + } + + verityMu.RLock() + defer verityMu.RUnlock() + + fd, err := vfsObj.OpenAt(ctx, fs.creds, &vfs.PathOperation{ + Root: d.lowerMerkleVD, + Start: d.lowerMerkleVD, + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + }) + if err == syserror.ENOENT { + return alertIntegrityViolation(err, fmt.Sprintf("Failed to open merkle file for %s: %v", childPath, err)) + } + if err != nil { + return err + } + + merkleSize, err := fd.GetXattr(ctx, &vfs.GetXattrOptions{ + Name: merkleSizeXattr, + Size: sizeOfStringInt32, + }) + + if err == syserror.ENODATA { + return alertIntegrityViolation(err, fmt.Sprintf("Failed to get xattr %s for merkle file of %s: %v", merkleSizeXattr, childPath, err)) + } + if err != nil { + return err + } + + size, err := strconv.Atoi(merkleSize) + if err != nil { + return alertIntegrityViolation(syserror.EINVAL, fmt.Sprintf("Failed to convert xattr %s for %s to int: %v", merkleSizeXattr, childPath, err)) + } + + fdReader := vfs.FileReadWriteSeeker{ + FD: fd, + Ctx: ctx, + } + + var buf bytes.Buffer + params := &merkletree.VerifyParams{ + Out: &buf, + Tree: &fdReader, + Size: int64(size), + Name: d.name, + Mode: uint32(stat.Mode), + UID: stat.UID, + GID: stat.GID, + ReadOffset: 0, + // Set read size to 0 so only the metadata is verified. + ReadSize: 0, + ExpectedRoot: d.rootHash, + DataAndTreeInSameFile: false, + } + if atomic.LoadUint32(&d.mode)&linux.S_IFMT == linux.S_IFDIR { + params.DataAndTreeInSameFile = true + } + + if _, err := merkletree.Verify(params); err != nil && err != io.EOF { + return alertIntegrityViolation(err, fmt.Sprintf("Verification stat for %s failed: %v", childPath, err)) + } + d.mode = uint32(stat.Mode) + d.uid = stat.UID + d.gid = stat.GID + return nil +} + // Preconditions: fs.renameMu must be locked. d.dirMu must be locked. func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name string, ds **[]*dentry) (*dentry, error) { if child, ok := parent.children[name]; ok { @@ -274,9 +377,27 @@ func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name s // runtime enable is allowed and the parent directory is // enabled, we should verify the child root hash here because // it may be cached before enabled. - if fs.allowRuntimeEnable && len(parent.rootHash) != 0 { - if _, err := fs.verifyChild(ctx, parent, child); err != nil { - return nil, err + if fs.allowRuntimeEnable { + if isEnabled(parent) { + if _, err := fs.verifyChild(ctx, parent, child); err != nil { + return nil, err + } + } + if isEnabled(child) { + vfsObj := fs.vfsfs.VirtualFilesystem() + mask := uint32(linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID) + stat, err := vfsObj.StatAt(ctx, fs.creds, &vfs.PathOperation{ + Root: child.lowerVD, + Start: child.lowerVD, + }, &vfs.StatOptions{ + Mask: mask, + }) + if err != nil { + return nil, err + } + if err := fs.verifyStat(ctx, child, stat); err != nil { + return nil, err + } } } return child, nil @@ -426,7 +547,6 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry, child.parent = parent child.name = name - // TODO(b/162788573): Verify child metadata. child.mode = uint32(stat.Mode) child.uid = stat.UID child.gid = stat.GID @@ -434,12 +554,18 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry, // Verify child root hash. This should always be performed unless in // allowRuntimeEnable mode and the parent directory hasn't been enabled // yet. - if !(fs.allowRuntimeEnable && len(parent.rootHash) == 0) { + if isEnabled(parent) { if _, err := fs.verifyChild(ctx, parent, child); err != nil { child.destroyLocked(ctx) return nil, err } } + if isEnabled(child) { + if err := fs.verifyStat(ctx, child, stat); err != nil { + child.destroyLocked(ctx) + return nil, err + } + } return child, nil } @@ -693,22 +819,24 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf // be called if a verity FD is created successfully. defer merkleWriter.DecRef(ctx) - parentMerkleWriter, err = rp.VirtualFilesystem().OpenAt(ctx, d.fs.creds, &vfs.PathOperation{ - Root: d.parent.lowerMerkleVD, - Start: d.parent.lowerMerkleVD, - }, &vfs.OpenOptions{ - Flags: linux.O_WRONLY | linux.O_APPEND, - }) - if err != nil { - if err == syserror.ENOENT { - parentPath, _ := d.fs.vfsfs.VirtualFilesystem().PathnameWithDeleted(ctx, d.fs.rootDentry.lowerVD, d.parent.lowerVD) - return nil, alertIntegrityViolation(err, fmt.Sprintf("Merkle file for %s expected but not found", parentPath)) + if d.parent != nil { + parentMerkleWriter, err = rp.VirtualFilesystem().OpenAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: d.parent.lowerMerkleVD, + Start: d.parent.lowerMerkleVD, + }, &vfs.OpenOptions{ + Flags: linux.O_WRONLY | linux.O_APPEND, + }) + if err != nil { + if err == syserror.ENOENT { + parentPath, _ := d.fs.vfsfs.VirtualFilesystem().PathnameWithDeleted(ctx, d.fs.rootDentry.lowerVD, d.parent.lowerVD) + return nil, alertIntegrityViolation(err, fmt.Sprintf("Merkle file for %s expected but not found", parentPath)) + } + return nil, err } - return nil, err + // parentMerkleWriter is cleaned up if any error occurs. IncRef + // will be called if a verity FD is created successfully. + defer parentMerkleWriter.DecRef(ctx) } - // parentMerkleWriter is cleaned up if any error occurs. IncRef - // will be called if a verity FD is created successfully. - defer parentMerkleWriter.DecRef(ctx) } fd := &fileDescription{ @@ -769,6 +897,8 @@ func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts } // StatAt implements vfs.FilesystemImpl.StatAt. +// TODO(b/170157489): Investigate whether stats other than Mode/UID/GID should +// be verified. func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) { var ds *[]*dentry fs.renameMu.RLock() @@ -786,6 +916,11 @@ func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf if err != nil { return linux.Statx{}, err } + if isEnabled(d) { + if err := fs.verifyStat(ctx, d, stat); err != nil { + return linux.Statx{}, err + } + } return stat, nil } diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go index 3129f290d..3eb972237 100644 --- a/pkg/sentry/fsimpl/verity/verity.go +++ b/pkg/sentry/fsimpl/verity/verity.go @@ -142,6 +142,14 @@ func (FilesystemType) Name() string { return Name } +// isEnabled checks whether the target is enabled with verity features. It +// should always be true if runtime enable is not allowed. In runtime enable +// mode, it returns true if the target has been enabled with +// ioctl(FS_IOC_ENABLE_VERITY). +func isEnabled(d *dentry) bool { + return !d.fs.allowRuntimeEnable || len(d.rootHash) != 0 +} + // alertIntegrityViolation alerts a violation of integrity, which usually means // unexpected modification to the file system is detected. In // noCrashOnVerificationFailure mode, it returns an error, otherwise it panic. @@ -245,12 +253,17 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt return nil, nil, err } - // TODO(b/162788573): Verify Metadata. d.mode = uint32(stat.Mode) d.uid = stat.UID d.gid = stat.GID - d.rootHash = make([]byte, len(iopts.RootHash)) + + if !fs.allowRuntimeEnable { + if err := fs.verifyStat(ctx, d, stat); err != nil { + return nil, nil, err + } + } + copy(d.rootHash, iopts.RootHash) d.vfsd.Init(d) @@ -488,6 +501,11 @@ func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linu if err != nil { return linux.Statx{}, err } + if isEnabled(fd.d) { + if err := fd.d.fs.verifyStat(ctx, fd.d, stat); err != nil { + return linux.Statx{}, err + } + } return stat, nil } @@ -516,8 +534,10 @@ func (fd *fileDescription) generateMerkle(ctx context.Context) ([]byte, uint64, FD: fd.merkleWriter, Ctx: ctx, } - var rootHash []byte - var dataSize uint64 + params := &merkletree.GenerateParams{ + TreeReader: &merkleReader, + TreeWriter: &merkleWriter, + } switch atomic.LoadUint32(&fd.d.mode) & linux.S_IFMT { case linux.S_IFREG: @@ -528,12 +548,14 @@ func (fd *fileDescription) generateMerkle(ctx context.Context) ([]byte, uint64, if err != nil { return nil, 0, err } - dataSize = stat.Size - rootHash, err = merkletree.Generate(&fdReader, int64(dataSize), &merkleReader, &merkleWriter, false /* dataAndTreeInSameFile */) - if err != nil { - return nil, 0, err - } + params.File = &fdReader + params.Size = int64(stat.Size) + params.Name = fd.d.name + params.Mode = uint32(stat.Mode) + params.UID = stat.UID + params.GID = stat.GID + params.DataAndTreeInSameFile = false case linux.S_IFDIR: // For a directory, generate a Merkle tree based on the root // hashes of its children that has already been written to the @@ -542,23 +564,32 @@ func (fd *fileDescription) generateMerkle(ctx context.Context) ([]byte, uint64, if err != nil { return nil, 0, err } - dataSize = merkleStat.Size - rootHash, err = merkletree.Generate(&merkleReader, int64(dataSize), &merkleReader, &merkleWriter, true /* dataAndTreeInSameFile */) + params.Size = int64(merkleStat.Size) + + stat, err := fd.lowerFD.Stat(ctx, vfs.StatOptions{}) if err != nil { return nil, 0, err } + + params.File = &merkleReader + params.Name = fd.d.name + params.Mode = uint32(stat.Mode) + params.UID = stat.UID + params.GID = stat.GID + params.DataAndTreeInSameFile = true default: // TODO(b/167728857): Investigate whether and how we should // enable other types of file. return nil, 0, syserror.EINVAL } - return rootHash, dataSize, nil + rootHash, err := merkletree.Generate(params) + return rootHash, uint64(params.Size), err } // enableVerity enables verity features on fd by generating a Merkle tree file // and stores its root hash in its parent directory's Merkle tree. -func (fd *fileDescription) enableVerity(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) { +func (fd *fileDescription) enableVerity(ctx context.Context, uio usermem.IO) (uintptr, error) { if !fd.d.fs.allowRuntimeEnable { return 0, syserror.EPERM } @@ -568,7 +599,11 @@ func (fd *fileDescription) enableVerity(ctx context.Context, uio usermem.IO, arg verityMu.Lock() defer verityMu.Unlock() - if fd.lowerFD == nil || fd.merkleReader == nil || fd.merkleWriter == nil || fd.parentMerkleWriter == nil { + // In allowRuntimeEnable mode, the underlying fd and read/write fd for + // the Merkle tree file should have all been initialized. For any file + // or directory other than the root, the parent Merkle tree file should + // have also been initialized. + if fd.lowerFD == nil || fd.merkleReader == nil || fd.merkleWriter == nil || (fd.parentMerkleWriter == nil && fd.d != fd.d.fs.rootDentry) { return 0, alertIntegrityViolation(syserror.EIO, "Unexpected verity fd: missing expected underlying fds") } @@ -577,26 +612,28 @@ func (fd *fileDescription) enableVerity(ctx context.Context, uio usermem.IO, arg return 0, err } - stat, err := fd.parentMerkleWriter.Stat(ctx, vfs.StatOptions{}) - if err != nil { - return 0, err - } + if fd.parentMerkleWriter != nil { + stat, err := fd.parentMerkleWriter.Stat(ctx, vfs.StatOptions{}) + if err != nil { + return 0, err + } - // Write the root hash of fd to the parent directory's Merkle tree - // file, as it should be part of the parent Merkle tree data. - // parentMerkleWriter is open with O_APPEND, so it should write - // directly to the end of the file. - if _, err = fd.parentMerkleWriter.Write(ctx, usermem.BytesIOSequence(rootHash), vfs.WriteOptions{}); err != nil { - return 0, err - } + // Write the root hash of fd to the parent directory's Merkle + // tree file, as it should be part of the parent Merkle tree + // data. parentMerkleWriter is open with O_APPEND, so it + // should write directly to the end of the file. + if _, err = fd.parentMerkleWriter.Write(ctx, usermem.BytesIOSequence(rootHash), vfs.WriteOptions{}); err != nil { + return 0, err + } - // Record the offset of the root hash of fd in parent directory's - // Merkle tree file. - if err := fd.merkleWriter.SetXattr(ctx, &vfs.SetXattrOptions{ - Name: merkleOffsetInParentXattr, - Value: strconv.Itoa(int(stat.Size)), - }); err != nil { - return 0, err + // Record the offset of the root hash of fd in parent directory's + // Merkle tree file. + if err := fd.merkleWriter.SetXattr(ctx, &vfs.SetXattrOptions{ + Name: merkleOffsetInParentXattr, + Value: strconv.Itoa(int(stat.Size)), + }); err != nil { + return 0, err + } } // Record the size of the data being hashed for fd. @@ -610,7 +647,45 @@ func (fd *fileDescription) enableVerity(ctx context.Context, uio usermem.IO, arg return 0, nil } -func (fd *fileDescription) getFlags(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) { +// measureVerity returns the root hash of fd, saved in args[2]. +func (fd *fileDescription) measureVerity(ctx context.Context, uio usermem.IO, verityDigest usermem.Addr) (uintptr, error) { + t := kernel.TaskFromContext(ctx) + var metadata linux.DigestMetadata + + // If allowRuntimeEnable is true, an empty fd.d.rootHash indicates that + // verity is not enabled for the file. If allowRuntimeEnable is false, + // this is an integrity violation because all files should have verity + // enabled, in which case fd.d.rootHash should be set. + if len(fd.d.rootHash) == 0 { + if fd.d.fs.allowRuntimeEnable { + return 0, syserror.ENODATA + } + return 0, alertIntegrityViolation(syserror.ENODATA, "Ioctl measureVerity: no root hash found") + } + + // The first part of VerityDigest is the metadata. + if _, err := metadata.CopyIn(t, verityDigest); err != nil { + return 0, err + } + if metadata.DigestSize < uint16(len(fd.d.rootHash)) { + return 0, syserror.EOVERFLOW + } + + // Populate the output digest size, since DigestSize is both input and + // output. + metadata.DigestSize = uint16(len(fd.d.rootHash)) + + // First copy the metadata. + if _, err := metadata.CopyOut(t, verityDigest); err != nil { + return 0, err + } + + // Now copy the root hash bytes to the memory after metadata. + _, err := t.CopyOutBytes(usermem.Addr(uintptr(verityDigest)+linux.SizeOfDigestMetadata), fd.d.rootHash) + return 0, err +} + +func (fd *fileDescription) verityFlags(ctx context.Context, uio usermem.IO, flags usermem.Addr) (uintptr, error) { f := int32(0) // All enabled files should store a root hash. This flag is not settable @@ -620,8 +695,7 @@ func (fd *fileDescription) getFlags(ctx context.Context, uio usermem.IO, args ar } t := kernel.TaskFromContext(ctx) - addr := args[2].Pointer() - _, err := primitive.CopyInt32Out(t, addr, f) + _, err := primitive.CopyInt32Out(t, flags, f) return 0, err } @@ -629,11 +703,15 @@ func (fd *fileDescription) getFlags(ctx context.Context, uio usermem.IO, args ar func (fd *fileDescription) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) { switch cmd := args[1].Uint(); cmd { case linux.FS_IOC_ENABLE_VERITY: - return fd.enableVerity(ctx, uio, args) + return fd.enableVerity(ctx, uio) + case linux.FS_IOC_MEASURE_VERITY: + return fd.measureVerity(ctx, uio, args[2].Pointer()) case linux.FS_IOC_GETFLAGS: - return fd.getFlags(ctx, uio, args) + return fd.verityFlags(ctx, uio, args[2].Pointer()) default: - return fd.lowerFD.Ioctl(ctx, uio, args) + // TODO(b/169682228): Investigate which ioctl commands should + // be allowed. + return 0, syserror.ENOSYS } } @@ -641,7 +719,7 @@ func (fd *fileDescription) Ioctl(ctx context.Context, uio usermem.IO, args arch. func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { // No need to verify if the file is not enabled yet in // allowRuntimeEnable mode. - if fd.d.fs.allowRuntimeEnable && len(fd.d.rootHash) == 0 { + if !isEnabled(fd.d) { return fd.lowerFD.PRead(ctx, dst, offset, opts) } @@ -678,9 +756,22 @@ func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, of Ctx: ctx, } - n, err := merkletree.Verify(dst.Writer(ctx), &dataReader, &merkleReader, int64(size), offset, dst.NumBytes(), fd.d.rootHash, false /* dataAndTreeInSameFile */) + n, err := merkletree.Verify(&merkletree.VerifyParams{ + Out: dst.Writer(ctx), + File: &dataReader, + Tree: &merkleReader, + Size: int64(size), + Name: fd.d.name, + Mode: fd.d.mode, + UID: fd.d.uid, + GID: fd.d.gid, + ReadOffset: offset, + ReadSize: dst.NumBytes(), + ExpectedRoot: fd.d.rootHash, + DataAndTreeInSameFile: false, + }) if err != nil { - return 0, alertIntegrityViolation(syserror.EINVAL, fmt.Sprintf("Verification failed: %v", err)) + return 0, alertIntegrityViolation(syserror.EIO, fmt.Sprintf("Verification failed: %v", err)) } return n, err } diff --git a/pkg/sentry/fsimpl/verity/verity_test.go b/pkg/sentry/fsimpl/verity/verity_test.go new file mode 100644 index 000000000..8d0926bc4 --- /dev/null +++ b/pkg/sentry/fsimpl/verity/verity_test.go @@ -0,0 +1,490 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package verity + +import ( + "fmt" + "io" + "math/rand" + "testing" + "time" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/kernel/contexttest" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/usermem" +) + +// rootMerkleFilename is the name of the root Merkle tree file. +const rootMerkleFilename = "root.verity" + +// maxDataSize is the maximum data size written to the file for test. +const maxDataSize = 100000 + +// newVerityRoot creates a new verity mount, and returns the root. The +// underlying file system is tmpfs. If the error is not nil, then cleanup +// should be called when the root is no longer needed. +func newVerityRoot(ctx context.Context, t *testing.T) (*vfs.VirtualFilesystem, vfs.VirtualDentry, error) { + rand.Seed(time.Now().UnixNano()) + vfsObj := &vfs.VirtualFilesystem{} + if err := vfsObj.Init(ctx); err != nil { + return nil, vfs.VirtualDentry{}, fmt.Errorf("VFS init: %v", err) + } + + vfsObj.MustRegisterFilesystemType("verity", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ + AllowUserMount: true, + }) + + vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ + AllowUserMount: true, + }) + + mntns, err := vfsObj.NewMountNamespace(ctx, auth.CredentialsFromContext(ctx), "", "verity", &vfs.MountOptions{ + GetFilesystemOptions: vfs.GetFilesystemOptions{ + InternalData: InternalFilesystemOptions{ + RootMerkleFileName: rootMerkleFilename, + LowerName: "tmpfs", + AllowRuntimeEnable: true, + NoCrashOnVerificationFailure: true, + }, + }, + }) + if err != nil { + return nil, vfs.VirtualDentry{}, fmt.Errorf("NewMountNamespace: %v", err) + } + root := mntns.Root() + t.Helper() + t.Cleanup(func() { + root.DecRef(ctx) + mntns.DecRef(ctx) + }) + return vfsObj, root, nil +} + +// newFileFD creates a new file in the verity mount, and returns the FD. The FD +// points to a file that has random data generated. +func newFileFD(ctx context.Context, vfsObj *vfs.VirtualFilesystem, root vfs.VirtualDentry, filePath string, mode linux.FileMode) (*vfs.FileDescription, int, error) { + creds := auth.CredentialsFromContext(ctx) + lowerRoot := root.Dentry().Impl().(*dentry).lowerVD + + // Create the file in the underlying file system. + lowerFD, err := vfsObj.OpenAt(ctx, creds, &vfs.PathOperation{ + Root: lowerRoot, + Start: lowerRoot, + Path: fspath.Parse(filePath), + }, &vfs.OpenOptions{ + Flags: linux.O_RDWR | linux.O_CREAT | linux.O_EXCL, + Mode: linux.ModeRegular | mode, + }) + if err != nil { + return nil, 0, err + } + + // Generate random data to be written to the file. + dataSize := rand.Intn(maxDataSize) + 1 + data := make([]byte, dataSize) + rand.Read(data) + + // Write directly to the underlying FD, since verity FD is read-only. + n, err := lowerFD.Write(ctx, usermem.BytesIOSequence(data), vfs.WriteOptions{}) + if err != nil { + return nil, 0, err + } + + if n != int64(len(data)) { + return nil, 0, fmt.Errorf("lowerFD.Write got write length %d, want %d", n, len(data)) + } + + lowerFD.DecRef(ctx) + + // Now open the verity file descriptor. + fd, err := vfsObj.OpenAt(ctx, creds, &vfs.PathOperation{ + Root: root, + Start: root, + Path: fspath.Parse(filePath), + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + Mode: linux.ModeRegular | mode, + }) + return fd, dataSize, err +} + +// corruptRandomBit randomly flips a bit in the file represented by fd. +func corruptRandomBit(ctx context.Context, fd *vfs.FileDescription, size int) error { + // Flip a random bit in the underlying file. + randomPos := int64(rand.Intn(size)) + byteToModify := make([]byte, 1) + if _, err := fd.PRead(ctx, usermem.BytesIOSequence(byteToModify), randomPos, vfs.ReadOptions{}); err != nil { + return fmt.Errorf("lowerFD.PRead: %v", err) + } + byteToModify[0] ^= 1 + if _, err := fd.PWrite(ctx, usermem.BytesIOSequence(byteToModify), randomPos, vfs.WriteOptions{}); err != nil { + return fmt.Errorf("lowerFD.PWrite: %v", err) + } + return nil +} + +// TestOpen ensures that when a file is created, the corresponding Merkle tree +// file and the root Merkle tree file exist. +func TestOpen(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + if _, _, err := newFileFD(ctx, vfsObj, root, filename, 0644); err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Ensure that the corresponding Merkle tree file is created. + lowerRoot := root.Dentry().Impl().(*dentry).lowerVD + if _, err = vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: lowerRoot, + Start: lowerRoot, + Path: fspath.Parse(merklePrefix + filename), + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + }); err != nil { + t.Errorf("OpenAt Merkle tree file %s: %v", merklePrefix+filename, err) + } + + // Ensure the root merkle tree file is created. + if _, err = vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: lowerRoot, + Start: lowerRoot, + Path: fspath.Parse(merklePrefix + rootMerkleFilename), + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + }); err != nil { + t.Errorf("OpenAt root Merkle tree file %s: %v", merklePrefix+rootMerkleFilename, err) + } +} + +// TestUnmodifiedFileSucceeds ensures that read from an untouched verity file +// succeeds after enabling verity for it. +func TestReadUnmodifiedFileSucceeds(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + fd, size, err := newFileFD(ctx, vfsObj, root, filename, 0644) + if err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Enable verity on the file and confirm a normal read succeeds. + var args arch.SyscallArguments + args[1] = arch.SyscallArgument{Value: linux.FS_IOC_ENABLE_VERITY} + if _, err := fd.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("Ioctl: %v", err) + } + + buf := make([]byte, size) + n, err := fd.PRead(ctx, usermem.BytesIOSequence(buf), 0 /* offset */, vfs.ReadOptions{}) + if err != nil && err != io.EOF { + t.Fatalf("fd.PRead: %v", err) + } + + if n != int64(size) { + t.Errorf("fd.PRead got read length %d, want %d", n, size) + } +} + +// TestReopenUnmodifiedFileSucceeds ensures that reopen an untouched verity file +// succeeds after enabling verity for it. +func TestReopenUnmodifiedFileSucceeds(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + fd, _, err := newFileFD(ctx, vfsObj, root, filename, 0644) + if err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Enable verity on the file and confirms a normal read succeeds. + var args arch.SyscallArguments + args[1] = arch.SyscallArgument{Value: linux.FS_IOC_ENABLE_VERITY} + if _, err := fd.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("Ioctl: %v", err) + } + + // Ensure reopening the verity enabled file succeeds. + if _, err = vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: root, + Start: root, + Path: fspath.Parse(filename), + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + Mode: linux.ModeRegular, + }); err != nil { + t.Errorf("reopen enabled file failed: %v", err) + } +} + +// TestModifiedFileFails ensures that read from a modified verity file fails. +func TestModifiedFileFails(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + fd, size, err := newFileFD(ctx, vfsObj, root, filename, 0644) + if err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Enable verity on the file. + var args arch.SyscallArguments + args[1] = arch.SyscallArgument{Value: linux.FS_IOC_ENABLE_VERITY} + if _, err := fd.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("Ioctl: %v", err) + } + + // Open a new lowerFD that's read/writable. + lowerVD := fd.Impl().(*fileDescription).d.lowerVD + + lowerFD, err := vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: lowerVD, + Start: lowerVD, + }, &vfs.OpenOptions{ + Flags: linux.O_RDWR, + }) + if err != nil { + t.Fatalf("OpenAt: %v", err) + } + + if err := corruptRandomBit(ctx, lowerFD, size); err != nil { + t.Fatalf("corruptRandomBit: %v", err) + } + + // Confirm that read from the modified file fails. + buf := make([]byte, size) + if _, err := fd.PRead(ctx, usermem.BytesIOSequence(buf), 0 /* offset */, vfs.ReadOptions{}); err == nil { + t.Fatalf("fd.PRead succeeded with modified file") + } +} + +// TestModifiedMerkleFails ensures that read from a verity file fails if the +// corresponding Merkle tree file is modified. +func TestModifiedMerkleFails(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + fd, size, err := newFileFD(ctx, vfsObj, root, filename, 0644) + if err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Enable verity on the file. + var args arch.SyscallArguments + args[1] = arch.SyscallArgument{Value: linux.FS_IOC_ENABLE_VERITY} + if _, err := fd.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("Ioctl: %v", err) + } + + // Open a new lowerMerkleFD that's read/writable. + lowerMerkleVD := fd.Impl().(*fileDescription).d.lowerMerkleVD + + lowerMerkleFD, err := vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: lowerMerkleVD, + Start: lowerMerkleVD, + }, &vfs.OpenOptions{ + Flags: linux.O_RDWR, + }) + if err != nil { + t.Fatalf("OpenAt: %v", err) + } + + // Flip a random bit in the Merkle tree file. + stat, err := lowerMerkleFD.Stat(ctx, vfs.StatOptions{}) + if err != nil { + t.Fatalf("stat: %v", err) + } + merkleSize := int(stat.Size) + if err := corruptRandomBit(ctx, lowerMerkleFD, merkleSize); err != nil { + t.Fatalf("corruptRandomBit: %v", err) + } + + // Confirm that read from a file with modified Merkle tree fails. + buf := make([]byte, size) + if _, err := fd.PRead(ctx, usermem.BytesIOSequence(buf), 0 /* offset */, vfs.ReadOptions{}); err == nil { + fmt.Println(buf) + t.Fatalf("fd.PRead succeeded with modified Merkle file") + } +} + +// TestModifiedParentMerkleFails ensures that open a verity enabled file in a +// verity enabled directory fails if the hashes related to the target file in +// the parent Merkle tree file is modified. +func TestModifiedParentMerkleFails(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + fd, _, err := newFileFD(ctx, vfsObj, root, filename, 0644) + if err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Enable verity on the file. + var args arch.SyscallArguments + args[1] = arch.SyscallArgument{Value: linux.FS_IOC_ENABLE_VERITY} + if _, err := fd.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("Ioctl: %v", err) + } + + // Enable verity on the parent directory. + parentFD, err := vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: root, + Start: root, + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + }) + if err != nil { + t.Fatalf("OpenAt: %v", err) + } + + if _, err := parentFD.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("Ioctl: %v", err) + } + + // Open a new lowerMerkleFD that's read/writable. + parentLowerMerkleVD := fd.Impl().(*fileDescription).d.parent.lowerMerkleVD + + parentLowerMerkleFD, err := vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: parentLowerMerkleVD, + Start: parentLowerMerkleVD, + }, &vfs.OpenOptions{ + Flags: linux.O_RDWR, + }) + if err != nil { + t.Fatalf("OpenAt: %v", err) + } + + // Flip a random bit in the parent Merkle tree file. + // This parent directory contains only one child, so any random + // modification in the parent Merkle tree should cause verification + // failure when opening the child file. + stat, err := parentLowerMerkleFD.Stat(ctx, vfs.StatOptions{}) + if err != nil { + t.Fatalf("stat: %v", err) + } + parentMerkleSize := int(stat.Size) + if err := corruptRandomBit(ctx, parentLowerMerkleFD, parentMerkleSize); err != nil { + t.Fatalf("corruptRandomBit: %v", err) + } + + parentLowerMerkleFD.DecRef(ctx) + + // Ensure reopening the verity enabled file fails. + if _, err = vfsObj.OpenAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{ + Root: root, + Start: root, + Path: fspath.Parse(filename), + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + Mode: linux.ModeRegular, + }); err == nil { + t.Errorf("OpenAt file with modified parent Merkle succeeded") + } +} + +// TestUnmodifiedStatSucceeds ensures that stat of an untouched verity file +// succeeds after enabling verity for it. +func TestUnmodifiedStatSucceeds(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + fd, _, err := newFileFD(ctx, vfsObj, root, filename, 0644) + if err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Enable verity on the file and confirms stat succeeds. + var args arch.SyscallArguments + args[1] = arch.SyscallArgument{Value: linux.FS_IOC_ENABLE_VERITY} + if _, err := fd.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("fd.Ioctl: %v", err) + } + + if _, err := fd.Stat(ctx, vfs.StatOptions{}); err != nil { + t.Errorf("fd.Stat: %v", err) + } +} + +// TestModifiedStatFails checks that getting stat for a file with modified stat +// should fail. +func TestModifiedStatFails(t *testing.T) { + ctx := contexttest.Context(t) + vfsObj, root, err := newVerityRoot(ctx, t) + if err != nil { + t.Fatalf("newVerityRoot: %v", err) + } + + filename := "verity-test-file" + fd, _, err := newFileFD(ctx, vfsObj, root, filename, 0644) + if err != nil { + t.Fatalf("newFileFD: %v", err) + } + + // Enable verity on the file. + var args arch.SyscallArguments + args[1] = arch.SyscallArgument{Value: linux.FS_IOC_ENABLE_VERITY} + if _, err := fd.Ioctl(ctx, nil /* uio */, args); err != nil { + t.Fatalf("fd.Ioctl: %v", err) + } + + lowerFD := fd.Impl().(*fileDescription).lowerFD + // Change the stat of the underlying file, and check that stat fails. + if err := lowerFD.SetStat(ctx, vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: uint32(linux.STATX_MODE), + Mode: 0777, + }, + }); err != nil { + t.Fatalf("lowerFD.SetStat: %v", err) + } + + if _, err := fd.Stat(ctx, vfs.StatOptions{}); err == nil { + t.Errorf("fd.Stat succeeded when it should fail") + } +} |