Enforce file size rlimits in VFS2

Updates #1035

PiperOrigin-RevId: 301255357

23 files changed, 103 insertions, 30 deletions

diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index c4a8f0b38..999485492 100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -713,7 +713,7 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin
 	if stat.Mask&^(linux.STATX_MODE|linux.STATX_UID|linux.STATX_GID|linux.STATX_ATIME|linux.STATX_MTIME|linux.STATX_SIZE) != 0 {
 		return syserror.EPERM
 	}
-	if err := vfs.CheckSetStat(creds, stat, uint16(atomic.LoadUint32(&d.mode))&^linux.S_IFMT, auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))); err != nil {
+	if err := vfs.CheckSetStat(ctx, creds, stat, uint16(atomic.LoadUint32(&d.mode))&^linux.S_IFMT, auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))); err != nil {
 		return err
 	}
 	if err := mnt.CheckBeginWrite(); err != nil {
diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go
index e95209661..3593eb1d5 100644
--- a/pkg/sentry/fsimpl/gofer/regular_file.go
+++ b/pkg/sentry/fsimpl/gofer/regular_file.go
@@ -126,6 +126,11 @@ func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
 	if opts.Flags != 0 {
 		return 0, syserror.EOPNOTSUPP
 	}
+	limit, err := vfs.CheckLimit(ctx, offset, src.NumBytes())
+	if err != nil {
+		return 0, err
+	}
+	src = src.TakeFirst64(limit)
 
 	d := fd.dentry()
 	d.metadataMu.Lock()
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go
index 08c691c47..274f7346f 100644
--- a/pkg/sentry/fsimpl/gofer/special_file.go
+++ b/pkg/sentry/fsimpl/gofer/special_file.go
@@ -107,6 +107,14 @@ func (fd *specialFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
 		return 0, syserror.EOPNOTSUPP
 	}
 
+	if fd.dentry().fileType() == linux.S_IFREG {
+		limit, err := vfs.CheckLimit(ctx, offset, src.NumBytes())
+		if err != nil {
+			return 0, err
+		}
+		src = src.TakeFirst64(limit)
+	}
+
 	// Do a buffered write. See rationale in PRead.
 	if d := fd.dentry(); d.fs.opts.interop != InteropModeShared {
 		d.touchCMtime(ctx)
diff --git a/pkg/sentry/fsimpl/host/default_file.go b/pkg/sentry/fsimpl/host/default_file.go
index 98682ba5e..459238603 100644
--- a/pkg/sentry/fsimpl/host/default_file.go
+++ b/pkg/sentry/fsimpl/host/default_file.go
@@ -112,7 +112,6 @@ func (f *defaultFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offs
 	if f.inode.isStream {
 		return 0, syserror.ESPIPE
 	}
-
 	return writeToHostFD(ctx, f.inode.hostFD, src, offset, int(opts.Flags))
 }
 
@@ -146,6 +145,12 @@ func writeToHostFD(ctx context.Context, hostFD int, src usermem.IOSequence, offs
 		return 0, syserror.EOPNOTSUPP
 	}
 
+	limit, err := vfs.CheckLimit(ctx, offset, src.NumBytes())
+	if err != nil {
+		return 0, err
+	}
+	src = src.TakeFirst64(limit)
+
 	var writer safemem.Writer
 	if offset == -1 {
 		writer = safemem.FromIOWriter{fd.NewReadWriter(hostFD)}
diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index 67c050c30..2eebcd60c 100644
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -270,7 +270,7 @@ func (i *inode) fstat(opts vfs.StatOptions) (linux.Statx, error) {
 }
 
 // SetStat implements kernfs.Inode.
-func (i *inode) SetStat(fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
+func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
 	s := opts.Stat
 
 	m := s.Mask
@@ -280,7 +280,7 @@ func (i *inode) SetStat(fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.Se
 	if m&^(linux.STATX_MODE|linux.STATX_SIZE|linux.STATX_ATIME|linux.STATX_MTIME) != 0 {
 		return syserror.EPERM
 	}
-	if err := vfs.CheckSetStat(creds, &s, uint16(i.Mode().Permissions()), i.uid, i.gid); err != nil {
+	if err := vfs.CheckSetStat(ctx, creds, &s, uint16(i.Mode().Permissions()), i.uid, i.gid); err != nil {
 		return err
 	}
 
@@ -382,7 +382,7 @@ type fileDescription struct {
 // SetStat implements vfs.FileDescriptionImpl.
 func (f *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
 	creds := auth.CredentialsFromContext(ctx)
-	return f.inode.SetStat(nil, creds, opts)
+	return f.inode.SetStat(ctx, nil, creds, opts)
 }
 
 // Stat implements vfs.FileDescriptionImpl.
diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
index c788d1d62..d8bddbafa 100644
--- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
+++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
@@ -64,7 +64,7 @@ func (f *DynamicBytesFile) Open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vf
 // SetStat implements Inode.SetStat. By default DynamicBytesFile doesn't allow
 // inode attributes to be changed. Override SetStat() making it call
 // f.InodeAttrs to allow it.
-func (*DynamicBytesFile) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*DynamicBytesFile) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
 
diff --git a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
index 331c82011..75c4bab1a 100644
--- a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
@@ -209,5 +209,5 @@ func (fd *GenericDirectoryFD) SetStat(ctx context.Context, opts vfs.SetStatOptio
 	fs := fd.filesystem()
 	creds := auth.CredentialsFromContext(ctx)
 	inode := fd.vfsfd.VirtualDentry().Dentry().Impl().(*Dentry).inode
-	return inode.SetStat(fs, creds, opts)
+	return inode.SetStat(ctx, fs, creds, opts)
 }
diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index 37fbe2eea..31da8b511 100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
@@ -636,7 +636,7 @@ func (fs *Filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts
 	if opts.Stat.Mask == 0 {
 		return nil
 	}
-	return inode.SetStat(fs.VFSFilesystem(), rp.Credentials(), opts)
+	return inode.SetStat(ctx, fs.VFSFilesystem(), rp.Credentials(), opts)
 }
 
 // StatAt implements vfs.FilesystemImpl.StatAt.
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 851c61b49..c612dcf07 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -234,14 +234,14 @@ func (a *InodeAttrs) Stat(*vfs.Filesystem, vfs.StatOptions) (linux.Statx, error)
 }
 
 // SetStat implements Inode.SetStat.
-func (a *InodeAttrs) SetStat(fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
+func (a *InodeAttrs) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
 	if opts.Stat.Mask == 0 {
 		return nil
 	}
 	if opts.Stat.Mask&^(linux.STATX_MODE|linux.STATX_UID|linux.STATX_GID) != 0 {
 		return syserror.EPERM
 	}
-	if err := vfs.CheckSetStat(creds, &opts.Stat, uint16(a.Mode().Permissions()), auth.KUID(atomic.LoadUint32(&a.uid)), auth.KGID(atomic.LoadUint32(&a.gid))); err != nil {
+	if err := vfs.CheckSetStat(ctx, creds, &opts.Stat, uint16(a.Mode().Permissions()), auth.KUID(atomic.LoadUint32(&a.uid)), auth.KGID(atomic.LoadUint32(&a.gid))); err != nil {
 		return err
 	}
 
@@ -566,7 +566,7 @@ func (s *StaticDirectory) Open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs
 }
 
 // SetStat implements Inode.SetStat not allowing inode attributes to be changed.
-func (*StaticDirectory) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*StaticDirectory) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
 
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index b12b216d2..794e38908 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
@@ -333,7 +333,7 @@ type inodeMetadata interface {
 	// vfs.FilesystemImpl.SetStatAt. Implementations are responsible for checking
 	// if the operation can be performed (see vfs.CheckSetStat() for common
 	// checks).
-	SetStat(fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error
+	SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error
 }
 
 // Precondition: All methods in this interface may only be called on directory
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_test.go b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
index 2875e6ffa..fb0d25ad7 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs_test.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
@@ -91,7 +91,7 @@ type attrs struct {
 	kernfs.InodeAttrs
 }
 
-func (*attrs) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*attrs) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
 
diff --git a/pkg/sentry/fsimpl/kernfs/symlink.go b/pkg/sentry/fsimpl/kernfs/symlink.go
index 92f709d29..5918d3309 100644
--- a/pkg/sentry/fsimpl/kernfs/symlink.go
+++ b/pkg/sentry/fsimpl/kernfs/symlink.go
@@ -56,6 +56,6 @@ func (s *StaticSymlink) Readlink(_ context.Context) (string, error) {
 }
 
 // SetStat implements Inode.SetStat not allowing inode attributes to be changed.
-func (*StaticSymlink) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*StaticSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
diff --git a/pkg/sentry/fsimpl/proc/subtasks.go b/pkg/sentry/fsimpl/proc/subtasks.go
index eb191aba4..a21313666 100644
--- a/pkg/sentry/fsimpl/proc/subtasks.go
+++ b/pkg/sentry/fsimpl/proc/subtasks.go
@@ -130,6 +130,6 @@ func (i *subtasksInode) Stat(vsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.
 }
 
 // SetStat implements Inode.SetStat not allowing inode attributes to be changed.
-func (*subtasksInode) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*subtasksInode) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
diff --git a/pkg/sentry/fsimpl/proc/task.go b/pkg/sentry/fsimpl/proc/task.go
index ceb427ffb..49d6efb0e 100644
--- a/pkg/sentry/fsimpl/proc/task.go
+++ b/pkg/sentry/fsimpl/proc/task.go
@@ -108,7 +108,7 @@ func (i *taskInode) Open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenO
 }
 
 // SetStat implements Inode.SetStat not allowing inode attributes to be changed.
-func (*taskInode) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*taskInode) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
 
diff --git a/pkg/sentry/fsimpl/proc/tasks_files.go b/pkg/sentry/fsimpl/proc/tasks_files.go
index d3d99393f..882c1981e 100644
--- a/pkg/sentry/fsimpl/proc/tasks_files.go
+++ b/pkg/sentry/fsimpl/proc/tasks_files.go
@@ -64,7 +64,7 @@ func (s *selfSymlink) Readlink(ctx context.Context) (string, error) {
 }
 
 // SetStat implements Inode.SetStat not allowing inode attributes to be changed.
-func (*selfSymlink) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*selfSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
 
@@ -102,7 +102,7 @@ func (s *threadSelfSymlink) Readlink(ctx context.Context) (string, error) {
 }
 
 // SetStat implements Inode.SetStat not allowing inode attributes to be changed.
-func (*threadSelfSymlink) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*threadSelfSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
 
@@ -114,8 +114,8 @@ type dynamicBytesFileSetAttr struct {
 }
 
 // SetStat implements Inode.SetStat.
-func (d *dynamicBytesFileSetAttr) SetStat(fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
-	return d.DynamicBytesFile.InodeAttrs.SetStat(fs, creds, opts)
+func (d *dynamicBytesFileSetAttr) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
+	return d.DynamicBytesFile.InodeAttrs.SetStat(ctx, fs, creds, opts)
 }
 
 // cpuStats contains the breakdown of CPU time for /proc/stat.
diff --git a/pkg/sentry/fsimpl/sys/sys.go b/pkg/sentry/fsimpl/sys/sys.go
index 9c8e63783..7abfd62f2 100644
--- a/pkg/sentry/fsimpl/sys/sys.go
+++ b/pkg/sentry/fsimpl/sys/sys.go
@@ -95,7 +95,7 @@ func (fs *filesystem) newDir(creds *auth.Credentials, mode linux.FileMode, conte
 }
 
 // SetStat implements Inode.SetStat not allowing inode attributes to be changed.
-func (*dir) SetStat(*vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
+func (*dir) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
 	return syserror.EPERM
 }
 
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index 6e8b4cae7..75d01b853 100644
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
@@ -575,7 +575,7 @@ func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts
 	if err != nil {
 		return err
 	}
-	return d.inode.setStat(rp.Credentials(), &opts.Stat)
+	return d.inode.setStat(ctx, rp.Credentials(), &opts.Stat)
 }
 
 // StatAt implements vfs.FilesystemImpl.StatAt.
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go
index 711442424..5a2896bf6 100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file.go
@@ -308,11 +308,18 @@ func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
 		return 0, nil
 	}
 	f := fd.inode().impl.(*regularFile)
-	end := offset + srclen
-	if end < offset {
+	if end := offset + srclen; end < offset {
 		// Overflow.
 		return 0, syserror.EFBIG
 	}
+
+	var err error
+	srclen, err = vfs.CheckLimit(ctx, offset, srclen)
+	if err != nil {
+		return 0, err
+	}
+	src = src.TakeFirst64(srclen)
+
 	f.inode.mu.Lock()
 	rw := getRegularFileReadWriter(f, offset)
 	n, err := src.CopyInTo(ctx, rw)
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index c18f1e46e..ff69372b3 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -299,14 +299,14 @@ func (i *inode) statTo(stat *linux.Statx) {
 	}
 }
 
-func (i *inode) setStat(creds *auth.Credentials, stat *linux.Statx) error {
+func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, stat *linux.Statx) error {
 	if stat.Mask == 0 {
 		return nil
 	}
 	if stat.Mask&^(linux.STATX_MODE|linux.STATX_UID|linux.STATX_GID|linux.STATX_ATIME|linux.STATX_MTIME|linux.STATX_CTIME|linux.STATX_SIZE) != 0 {
 		return syserror.EPERM
 	}
-	if err := vfs.CheckSetStat(creds, stat, uint16(atomic.LoadUint32(&i.mode))&^linux.S_IFMT, auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid))); err != nil {
+	if err := vfs.CheckSetStat(ctx, creds, stat, uint16(atomic.LoadUint32(&i.mode))&^linux.S_IFMT, auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid))); err != nil {
 		return err
 	}
 	i.mu.Lock()
@@ -464,5 +464,5 @@ func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linu
 // SetStat implements vfs.FileDescriptionImpl.SetStat.
 func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
 	creds := auth.CredentialsFromContext(ctx)
-	return fd.inode().setStat(creds, &opts.Stat)
+	return fd.inode().setStat(ctx, creds, &opts.Stat)
 }
diff --git a/pkg/sentry/syscalls/linux/vfs2/setstat.go b/pkg/sentry/syscalls/linux/vfs2/setstat.go
index 9250659ff..136453ccc 100644
--- a/pkg/sentry/syscalls/linux/vfs2/setstat.go
+++ b/pkg/sentry/syscalls/linux/vfs2/setstat.go
@@ -173,12 +173,13 @@ func Truncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 		return 0, nil, err
 	}
 
-	return 0, nil, setstatat(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink, &vfs.SetStatOptions{
+	err = setstatat(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink, &vfs.SetStatOptions{
 		Stat: linux.Statx{
 			Mask: linux.STATX_SIZE,
 			Size: uint64(length),
 		},
 	})
+	return 0, nil, handleSetSizeError(t, err)
 }
 
 // Ftruncate implements Linux syscall ftruncate(2).
@@ -196,12 +197,13 @@ func Ftruncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
 	}
 	defer file.DecRef()
 
-	return 0, nil, file.SetStat(t, vfs.SetStatOptions{
+	err := file.SetStat(t, vfs.SetStatOptions{
 		Stat: linux.Statx{
 			Mask: linux.STATX_SIZE,
 			Size: uint64(length),
 		},
 	})
+	return 0, nil, handleSetSizeError(t, err)
 }
 
 // Utime implements Linux syscall utime(2).
@@ -378,3 +380,12 @@ func setstatat(t *kernel.Task, dirfd int32, path fspath.Path, shouldAllowEmptyPa
 		FollowFinalSymlink: bool(shouldFollowFinalSymlink),
 	}, opts)
 }
+
+func handleSetSizeError(t *kernel.Task, err error) error {
+	if err == syserror.ErrExceedsFileSizeLimit {
+		// Convert error to EFBIG and send a SIGXFSZ per setrlimit(2).
+		t.SendSignal(kernel.SignalInfoNoInfo(linux.SIGXFSZ, t, t))
+		return syserror.EFBIG
+	}
+	return err
+}
diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD
index cb4deb068..a2a06fc8f 100644
--- a/pkg/sentry/vfs/BUILD
+++ b/pkg/sentry/vfs/BUILD
@@ -51,6 +51,7 @@ go_library(
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/lock",
         "//pkg/sentry/kernel/auth",
+        "//pkg/sentry/limits",
         "//pkg/sentry/memmap",
         "//pkg/sync",
         "//pkg/syserror",
diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go
index 45191d1c3..d45e602ce 100644
--- a/pkg/sentry/vfs/file_description_impl_util.go
+++ b/pkg/sentry/vfs/file_description_impl_util.go
@@ -339,6 +339,11 @@ func (fd *DynamicBytesFileDescriptionImpl) pwriteLocked(ctx context.Context, src
 	if opts.Flags&^(linux.RWF_HIPRI|linux.RWF_DSYNC|linux.RWF_SYNC) != 0 {
 		return 0, syserror.EOPNOTSUPP
 	}
+	limit, err := CheckLimit(ctx, offset, src.NumBytes())
+	if err != nil {
+		return 0, err
+	}
+	src = src.TakeFirst64(limit)
 
 	writable, ok := fd.data.(WritableDynamicBytesSource)
 	if !ok {
diff --git a/pkg/sentry/vfs/permissions.go b/pkg/sentry/vfs/permissions.go
index 8e250998a..2c8f23f55 100644
--- a/pkg/sentry/vfs/permissions.go
+++ b/pkg/sentry/vfs/permissions.go
@@ -15,8 +15,12 @@
 package vfs
 
 import (
+	"math"
+
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/limits"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
@@ -147,7 +151,16 @@ func MayWriteFileWithOpenFlags(flags uint32) bool {
 // CheckSetStat checks that creds has permission to change the metadata of a
 // file with the given permissions, UID, and GID as specified by stat, subject
 // to the rules of Linux's fs/attr.c:setattr_prepare().
-func CheckSetStat(creds *auth.Credentials, stat *linux.Statx, mode uint16, kuid auth.KUID, kgid auth.KGID) error {
+func CheckSetStat(ctx context.Context, creds *auth.Credentials, stat *linux.Statx, mode uint16, kuid auth.KUID, kgid auth.KGID) error {
+	if stat.Mask&linux.STATX_SIZE != 0 {
+		limit, err := CheckLimit(ctx, 0, int64(stat.Size))
+		if err != nil {
+			return err
+		}
+		if limit < int64(stat.Size) {
+			return syserror.ErrExceedsFileSizeLimit
+		}
+	}
 	if stat.Mask&linux.STATX_MODE != 0 {
 		if !CanActAsOwner(creds, kuid) {
 			return syserror.EPERM
@@ -205,3 +218,21 @@ func CanActAsOwner(creds *auth.Credentials, kuid auth.KUID) bool {
 func HasCapabilityOnFile(creds *auth.Credentials, cp linux.Capability, kuid auth.KUID, kgid auth.KGID) bool {
 	return creds.HasCapability(cp) && creds.UserNamespace.MapFromKUID(kuid).Ok() && creds.UserNamespace.MapFromKGID(kgid).Ok()
 }
+
+// CheckLimit enforces file size rlimits. It returns error if the write
+// operation must not proceed. Otherwise it returns the max length allowed to
+// without violating the limit.
+func CheckLimit(ctx context.Context, offset, size int64) (int64, error) {
+	fileSizeLimit := limits.FromContext(ctx).Get(limits.FileSize).Cur
+	if fileSizeLimit > math.MaxInt64 {
+		return size, nil
+	}
+	if offset >= int64(fileSizeLimit) {
+		return 0, syserror.ErrExceedsFileSizeLimit
+	}
+	remaining := int64(fileSizeLimit) - offset
+	if remaining < size {
+		return remaining, nil
+	}
+	return size, nil
+}