Merge release-20200818.0-55-g247dcd62d (automated)

8 files changed, 62 insertions, 39 deletions

diff --git a/pkg/abi/linux/fs.go b/pkg/abi/linux/fs.go
index 158d2db5b..2b1ef0d4e 100644
--- a/pkg/abi/linux/fs.go
+++ b/pkg/abi/linux/fs.go
@@ -44,17 +44,18 @@ type Statfs struct {
 	// Type is one of the filesystem magic values, defined above.
 	Type uint64
 
-	// BlockSize is the data block size.
+	// BlockSize is the optimal transfer block size in bytes.
 	BlockSize int64
 
-	// Blocks is the number of data blocks in use.
+	// Blocks is the maximum number of data blocks the filesystem may store, in
+	// units of BlockSize.
 	Blocks uint64
 
-	// BlocksFree is the number of free blocks.
+	// BlocksFree is the number of free data blocks, in units of BlockSize.
 	BlocksFree uint64
 
-	// BlocksAvailable is the number of blocks free for use by
-	// unprivileged users.
+	// BlocksAvailable is the number of data blocks free for use by
+	// unprivileged users, in units of BlockSize.
 	BlocksAvailable uint64
 
 	// Files is the number of used file nodes on the filesystem.
diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go
index e003ac274..7d829e731 100644
--- a/pkg/abi/linux/linux_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go
@@ -154,7 +154,7 @@ func (s *Statx) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (s *Statx) Packed() bool {
-    return s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed()
+    return s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -169,7 +169,7 @@ func (s *Statx) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (s *Statx) UnmarshalUnsafe(src []byte) {
-    if s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
+    if s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
         safecopy.CopyOut(unsafe.Pointer(s), src)
     } else {
         // Type Statx doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -180,7 +180,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
+    if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         s.MarshalBytes(buf) // escapes: fallback.
@@ -236,7 +236,7 @@ func (s *Statx) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (s *Statx) WriteTo(writer io.Writer) (int64, error) {
-    if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
+    if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, s.SizeBytes())
         s.MarshalBytes(buf)
@@ -644,7 +644,7 @@ func (f *FUSEHeaderIn) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (f *FUSEHeaderIn) UnmarshalUnsafe(src []byte) {
-    if f.Opcode.Packed() && f.Unique.Packed() {
+    if f.Unique.Packed() && f.Opcode.Packed() {
         safecopy.CopyOut(unsafe.Pointer(f), src)
     } else {
         // Type FUSEHeaderIn doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -685,7 +685,7 @@ func (f *FUSEHeaderIn) CopyOut(task marshal.Task, addr usermem.Addr) (int, error
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (f *FUSEHeaderIn) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !f.Opcode.Packed() && f.Unique.Packed() {
+    if !f.Unique.Packed() && f.Opcode.Packed() {
         // Type FUSEHeaderIn doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(f.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -2022,12 +2022,12 @@ func (i *IPTEntry) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (i *IPTEntry) Packed() bool {
-    return i.Counters.Packed() && i.IP.Packed()
+    return i.IP.Packed() && i.Counters.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
 func (i *IPTEntry) MarshalUnsafe(dst []byte) {
-    if i.IP.Packed() && i.Counters.Packed() {
+    if i.Counters.Packed() && i.IP.Packed() {
         safecopy.CopyIn(dst, unsafe.Pointer(i))
     } else {
         // Type IPTEntry doesn't have a packed layout in memory, fallback to MarshalBytes.
@@ -2048,7 +2048,7 @@ func (i *IPTEntry) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (i *IPTEntry) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !i.Counters.Packed() && i.IP.Packed() {
+    if !i.IP.Packed() && i.Counters.Packed() {
         // Type IPTEntry doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         i.MarshalBytes(buf) // escapes: fallback.
@@ -2104,7 +2104,7 @@ func (i *IPTEntry) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (i *IPTEntry) WriteTo(writer io.Writer) (int64, error) {
-    if !i.IP.Packed() && i.Counters.Packed() {
+    if !i.Counters.Packed() && i.IP.Packed() {
         // Type IPTEntry doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, i.SizeBytes())
         i.MarshalBytes(buf)
@@ -2210,12 +2210,12 @@ func (i *IPTIP) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (i *IPTIP) Packed() bool {
-    return i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed()
+    return i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
 func (i *IPTIP) MarshalUnsafe(dst []byte) {
-    if i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+    if i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
         safecopy.CopyIn(dst, unsafe.Pointer(i))
     } else {
         // Type IPTIP doesn't have a packed layout in memory, fallback to MarshalBytes.
@@ -2225,7 +2225,7 @@ func (i *IPTIP) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (i *IPTIP) UnmarshalUnsafe(src []byte) {
-    if i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+    if i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         safecopy.CopyOut(unsafe.Pointer(i), src)
     } else {
         // Type IPTIP doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -2292,7 +2292,7 @@ func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (i *IPTIP) WriteTo(writer io.Writer) (int64, error) {
-    if !i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+    if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
         // Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, i.SizeBytes())
         i.MarshalBytes(buf)
@@ -3001,7 +3001,7 @@ func (i *IP6TEntry) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (i *IP6TEntry) Packed() bool {
-    return i.Counters.Packed() && i.IPv6.Packed()
+    return i.IPv6.Packed() && i.Counters.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -3198,7 +3198,7 @@ func (i *IP6TIP) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (i *IP6TIP) Packed() bool {
-    return i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed()
+    return i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -3254,7 +3254,7 @@ func (i *IP6TIP) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (i *IP6TIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -3280,7 +3280,7 @@ func (i *IP6TIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (i *IP6TIP) WriteTo(writer io.Writer) (int64, error) {
-    if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, i.SizeBytes())
         i.MarshalBytes(buf)
diff --git a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
index 1fc7f49df..7e5f141d4 100644
--- a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
@@ -344,7 +344,7 @@ func (s *Stat) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
+    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
diff --git a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
index f630c7148..33fb22105 100644
--- a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
@@ -300,7 +300,7 @@ func (s *Stat) Packed() bool {
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
 func (s *Stat) MarshalUnsafe(dst []byte) {
-    if s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
         safecopy.CopyIn(dst, unsafe.Pointer(s))
     } else {
         // Type Stat doesn't have a packed layout in memory, fallback to MarshalBytes.
diff --git a/pkg/sentry/fs/tmpfs/tmpfs.go b/pkg/sentry/fs/tmpfs/tmpfs.go
index b095312fe..998b697ca 100644
--- a/pkg/sentry/fs/tmpfs/tmpfs.go
+++ b/pkg/sentry/fs/tmpfs/tmpfs.go
@@ -16,6 +16,8 @@
 package tmpfs
 
 import (
+	"math"
+
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -32,9 +34,15 @@ import (
 var fsInfo = fs.Info{
 	Type: linux.TMPFS_MAGIC,
 
+	// tmpfs currently does not support configurable size limits. In Linux,
+	// such a tmpfs mount will return f_blocks == f_bfree == f_bavail == 0 from
+	// statfs(2). However, many applications treat this as having a size limit
+	// of 0. To work around this, claim to have a very large but non-zero size,
+	// chosen to ensure that BlockSize * Blocks does not overflow int64 (which
+	// applications may also handle incorrectly).
 	// TODO(b/29637826): allow configuring a tmpfs size and enforce it.
-	TotalBlocks: 0,
-	FreeBlocks:  0,
+	TotalBlocks: math.MaxInt64 / usermem.PageSize,
+	FreeBlocks:  math.MaxInt64 / usermem.PageSize,
 }
 
 // rename implements fs.InodeOperations.Rename for tmpfs nodes.
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index 7924a0911..eddfeab76 100644
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
@@ -25,7 +25,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // Sync implements vfs.FilesystemImpl.Sync.
@@ -706,16 +705,7 @@ func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linu
 	if _, err := resolveLocked(ctx, rp); err != nil {
 		return linux.Statfs{}, err
 	}
-	statfs := linux.Statfs{
-		Type:         linux.TMPFS_MAGIC,
-		BlockSize:    usermem.PageSize,
-		FragmentSize: usermem.PageSize,
-		NameLength:   linux.NAME_MAX,
-		// TODO(b/29637826): Allow configuring a tmpfs size and enforce it.
-		Blocks:     0,
-		BlocksFree: 0,
-	}
-	return statfs, nil
+	return globalStatfs, nil
 }
 
 // SymlinkAt implements vfs.FilesystemImpl.SymlinkAt.
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index 428f62aaa..a7fdf19ca 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -201,6 +201,25 @@ func (fs *filesystem) Release(ctx context.Context) {
 	fs.vfsfs.VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor)
 }
 
+// immutable
+var globalStatfs = linux.Statfs{
+	Type:         linux.TMPFS_MAGIC,
+	BlockSize:    usermem.PageSize,
+	FragmentSize: usermem.PageSize,
+	NameLength:   linux.NAME_MAX,
+
+	// tmpfs currently does not support configurable size limits. In Linux,
+	// such a tmpfs mount will return f_blocks == f_bfree == f_bavail == 0 from
+	// statfs(2). However, many applications treat this as having a size limit
+	// of 0. To work around this, claim to have a very large but non-zero size,
+	// chosen to ensure that BlockSize * Blocks does not overflow int64 (which
+	// applications may also handle incorrectly).
+	// TODO(b/29637826): allow configuring a tmpfs size and enforce it.
+	Blocks:          math.MaxInt64 / usermem.PageSize,
+	BlocksFree:      math.MaxInt64 / usermem.PageSize,
+	BlocksAvailable: math.MaxInt64 / usermem.PageSize,
+}
+
 // dentry implements vfs.DentryImpl.
 type dentry struct {
 	vfsd vfs.Dentry
@@ -698,6 +717,11 @@ func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions)
 	return nil
 }
 
+// StatFS implements vfs.FileDescriptionImpl.StatFS.
+func (fd *fileDescription) StatFS(ctx context.Context) (linux.Statfs, error) {
+	return globalStatfs, nil
+}
+
 // Listxattr implements vfs.FileDescriptionImpl.Listxattr.
 func (fd *fileDescription) Listxattr(ctx context.Context, size uint64) ([]string, error) {
 	return fd.inode().listxattr(size)
diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index eba2eac30..2dac9ad14 100644
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -3,11 +3,11 @@ package ring0
 import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"io"
 	"reflect"
 
 	"fmt"
 	"gvisor.dev/gvisor/pkg/usermem"
+	"io"
 )
 
 // Useful bits.