diff options
| -rwxr-xr-x | pkg/bits/bits32.go | 8 | ||||
| -rwxr-xr-x | pkg/bits/bits64.go | 8 | ||||
| -rwxr-xr-x | pkg/sentry/syscalls/linux/vfs2/filesystem.go | 2 | ||||
| -rwxr-xr-x | pkg/sentry/syscalls/linux/vfs2/getdents.go | 4 | ||||
| -rwxr-xr-x | pkg/sentry/syscalls/linux/vfs2/stat.go | 7 | ||||
| -rwxr-xr-x | pkg/sentry/vfs/resolving_path.go | 16 |
6 files changed, 39 insertions, 6 deletions
diff --git a/pkg/bits/bits32.go b/pkg/bits/bits32.go index 4e9e45dce..28134a9e7 100755 --- a/pkg/bits/bits32.go +++ b/pkg/bits/bits32.go @@ -23,3 +23,11 @@ func Mask32(is ...int) uint32 { func MaskOf32(i int) uint32 { return uint32(1) << uint32(i) } + +// IsPowerOfTwo returns true if v is power of 2. +func IsPowerOfTwo32(v uint32) bool { + if v == 0 { + return false + } + return v&(v-1) == 0 +} diff --git a/pkg/bits/bits64.go b/pkg/bits/bits64.go index f49158792..73117b19b 100755 --- a/pkg/bits/bits64.go +++ b/pkg/bits/bits64.go @@ -23,3 +23,11 @@ func Mask64(is ...int) uint64 { func MaskOf64(i int) uint64 { return uint64(1) << uint64(i) } + +// IsPowerOfTwo returns true if v is power of 2. +func IsPowerOfTwo64(v uint64) bool { + if v == 0 { + return false + } + return v&(v-1) == 0 +} diff --git a/pkg/sentry/syscalls/linux/vfs2/filesystem.go b/pkg/sentry/syscalls/linux/vfs2/filesystem.go index fc5ceea4c..a859095e2 100755 --- a/pkg/sentry/syscalls/linux/vfs2/filesystem.go +++ b/pkg/sentry/syscalls/linux/vfs2/filesystem.go @@ -250,7 +250,7 @@ func rmdirat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr) error { if err != nil { return err } - tpop, err := getTaskPathOperation(t, dirfd, path, disallowEmptyPath, followFinalSymlink) + tpop, err := getTaskPathOperation(t, dirfd, path, disallowEmptyPath, nofollowFinalSymlink) if err != nil { return err } diff --git a/pkg/sentry/syscalls/linux/vfs2/getdents.go b/pkg/sentry/syscalls/linux/vfs2/getdents.go index ddc140b65..a61cc5059 100755 --- a/pkg/sentry/syscalls/linux/vfs2/getdents.go +++ b/pkg/sentry/syscalls/linux/vfs2/getdents.go @@ -97,7 +97,7 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error { // char d_name[]; /* Filename (null-terminated) */ // }; size := 8 + 8 + 2 + 1 + 1 + len(dirent.Name) - if size < cb.remaining { + if size > cb.remaining { return syserror.EINVAL } buf = cb.t.CopyScratchBuffer(size) @@ -125,7 +125,7 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error { panic(fmt.Sprintf("unsupported sizeof(unsigned long): %d", cb.t.Arch().Width())) } size := 8 + 8 + 2 + 1 + 1 + 1 + len(dirent.Name) - if size < cb.remaining { + if size > cb.remaining { return syserror.EINVAL } buf = cb.t.CopyScratchBuffer(size) diff --git a/pkg/sentry/syscalls/linux/vfs2/stat.go b/pkg/sentry/syscalls/linux/vfs2/stat.go index 068243132..fdfe49243 100755 --- a/pkg/sentry/syscalls/linux/vfs2/stat.go +++ b/pkg/sentry/syscalls/linux/vfs2/stat.go @@ -16,6 +16,7 @@ package vfs2 import ( "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/bits" "gvisor.dev/gvisor/pkg/fspath" "gvisor.dev/gvisor/pkg/gohacks" "gvisor.dev/gvisor/pkg/sentry/arch" @@ -153,7 +154,11 @@ func Statx(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if flags&^(linux.AT_EMPTY_PATH|linux.AT_SYMLINK_NOFOLLOW|linux.AT_STATX_SYNC_TYPE) != 0 { return 0, nil, syserror.EINVAL } - + // Make sure that only one sync type option is set. + syncType := uint32(flags & linux.AT_STATX_SYNC_TYPE) + if syncType != 0 && !bits.IsPowerOfTwo32(syncType) { + return 0, nil, syserror.EINVAL + } if mask&linux.STATX__RESERVED != 0 { return 0, nil, syserror.EINVAL } diff --git a/pkg/sentry/vfs/resolving_path.go b/pkg/sentry/vfs/resolving_path.go index eb4ebb511..8f31495da 100755 --- a/pkg/sentry/vfs/resolving_path.go +++ b/pkg/sentry/vfs/resolving_path.go @@ -329,10 +329,22 @@ func (rp *ResolvingPath) ResolveComponent(d *Dentry) (*Dentry, error) { // component in pcs represents a symbolic link, the symbolic link should be // followed. // +// If path is terminated with '/', the '/' is considered the last element and +// any symlink before that is followed: +// - For most non-creating walks, the last path component is handled by +// fs/namei.c:lookup_last(), which sets LOOKUP_FOLLOW if the first byte +// after the path component is non-NULL (which is only possible if it's '/') +// and the path component is of type LAST_NORM. +// +// - For open/openat/openat2 without O_CREAT, the last path component is +// handled by fs/namei.c:do_last(), which does the same, though without the +// LAST_NORM check. +// // Preconditions: !rp.Done(). func (rp *ResolvingPath) ShouldFollowSymlink() bool { - // Non-final symlinks are always followed. - return rp.flags&rpflagsFollowFinalSymlink != 0 || !rp.Final() + // Non-final symlinks are always followed. Paths terminated with '/' are also + // always followed. + return rp.flags&rpflagsFollowFinalSymlink != 0 || !rp.Final() || rp.MustBeDir() } // HandleSymlink is called when the current path component is a symbolic link |