diff options
| -rw-r--r-- | pkg/sentry/fs/tmpfs/inode_file.go | 10 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_splice.go | 16 | ||||
| -rw-r--r-- | test/syscalls/linux/splice.cc | 56 |
3 files changed, 70 insertions, 12 deletions
diff --git a/pkg/sentry/fs/tmpfs/inode_file.go b/pkg/sentry/fs/tmpfs/inode_file.go index dabc10662..25abbc151 100644 --- a/pkg/sentry/fs/tmpfs/inode_file.go +++ b/pkg/sentry/fs/tmpfs/inode_file.go @@ -17,6 +17,7 @@ package tmpfs import ( "fmt" "io" + "math" "time" "gvisor.dev/gvisor/pkg/abi/linux" @@ -444,10 +445,15 @@ func (rw *fileReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error) defer rw.f.dataMu.Unlock() // Compute the range to write. - end := fs.WriteEndOffset(rw.offset, int64(srcs.NumBytes())) - if end == rw.offset { // srcs.NumBytes() == 0? + if srcs.NumBytes() == 0 { + // Nothing to do. return 0, nil } + end := fs.WriteEndOffset(rw.offset, int64(srcs.NumBytes())) + if end == math.MaxInt64 { + // Overflow. + return 0, syserror.EINVAL + } // Check if seals prevent either file growth or all writes. switch { diff --git a/pkg/sentry/syscalls/linux/sys_splice.go b/pkg/sentry/syscalls/linux/sys_splice.go index f43d6c155..fd642834b 100644 --- a/pkg/sentry/syscalls/linux/sys_splice.go +++ b/pkg/sentry/syscalls/linux/sys_splice.go @@ -25,6 +25,10 @@ import ( // doSplice implements a blocking splice operation. func doSplice(t *kernel.Task, outFile, inFile *fs.File, opts fs.SpliceOpts, nonBlocking bool) (int64, error) { + if opts.Length < 0 || opts.SrcStart < 0 || opts.DstStart < 0 { + return 0, syserror.EINVAL + } + var ( total int64 n int64 @@ -82,11 +86,6 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc offsetAddr := args[2].Pointer() count := int64(args[3].SizeT()) - // Don't send a negative number of bytes. - if count < 0 { - return 0, nil, syserror.EINVAL - } - // Get files. inFile := t.GetFile(inFD) if inFile == nil { @@ -136,11 +135,6 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc return 0, nil, err } - // The offset must be valid. - if offset < 0 { - return 0, nil, syserror.EINVAL - } - // Do the splice. n, err = doSplice(t, outFile, inFile, fs.SpliceOpts{ Length: count, @@ -227,6 +221,7 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if _, err := t.CopyIn(outOffset, &offset); err != nil { return 0, nil, err } + // Use the destination offset. opts.DstOffset = true opts.DstStart = offset @@ -244,6 +239,7 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if _, err := t.CopyIn(inOffset, &offset); err != nil { return 0, nil, err } + // Use the source offset. opts.SrcOffset = true opts.SrcStart = offset diff --git a/test/syscalls/linux/splice.cc b/test/syscalls/linux/splice.cc index 85232cb1f..faa1247f6 100644 --- a/test/syscalls/linux/splice.cc +++ b/test/syscalls/linux/splice.cc @@ -60,6 +60,62 @@ TEST(SpliceTest, TwoRegularFiles) { SyscallFailsWithErrno(EINVAL)); } +int memfd_create(const std::string& name, unsigned int flags) { + return syscall(__NR_memfd_create, name.c_str(), flags); +} + +TEST(SpliceTest, NegativeOffset) { + // Create a new pipe. + int fds[2]; + ASSERT_THAT(pipe(fds), SyscallSucceeds()); + const FileDescriptor rfd(fds[0]); + const FileDescriptor wfd(fds[1]); + + // Fill the pipe. + std::vector<char> buf(kPageSize); + RandomizeBuffer(buf.data(), buf.size()); + ASSERT_THAT(write(wfd.get(), buf.data(), buf.size()), + SyscallSucceedsWithValue(kPageSize)); + + // Open the output file as write only. + int fd; + EXPECT_THAT(fd = memfd_create("negative", 0), SyscallSucceeds()); + const FileDescriptor out_fd(fd); + + loff_t out_offset = 0xffffffffffffffffull; + constexpr int kSize = 2; + EXPECT_THAT(splice(rfd.get(), nullptr, out_fd.get(), &out_offset, kSize, 0), + SyscallFailsWithErrno(EINVAL)); +} + +// Write offset + size overflows int64. +// +// This is a regression test for b/148041624. +TEST(SpliceTest, WriteOverflow) { + // Create a new pipe. + int fds[2]; + ASSERT_THAT(pipe(fds), SyscallSucceeds()); + const FileDescriptor rfd(fds[0]); + const FileDescriptor wfd(fds[1]); + + // Fill the pipe. + std::vector<char> buf(kPageSize); + RandomizeBuffer(buf.data(), buf.size()); + ASSERT_THAT(write(wfd.get(), buf.data(), buf.size()), + SyscallSucceedsWithValue(kPageSize)); + + // Open the output file. + int fd; + EXPECT_THAT(fd = memfd_create("overflow", 0), SyscallSucceeds()); + const FileDescriptor out_fd(fd); + + // out_offset + kSize overflows INT64_MAX. + loff_t out_offset = 0x7ffffffffffffffeull; + constexpr int kSize = 3; + EXPECT_THAT(splice(rfd.get(), nullptr, out_fd.get(), &out_offset, kSize, 0), + SyscallFailsWithErrno(EINVAL)); +} + TEST(SpliceTest, SamePipe) { // Create a new pipe. int fds[2]; |