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-rwxr-xr-xpkg/sentry/syscalls/linux/vfs2/getdents.go20
1 files changed, 16 insertions, 4 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/getdents.go b/pkg/sentry/syscalls/linux/vfs2/getdents.go
index a61cc5059..62e98817d 100755
--- a/pkg/sentry/syscalls/linux/vfs2/getdents.go
+++ b/pkg/sentry/syscalls/linux/vfs2/getdents.go
@@ -97,6 +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)
+ size = (size + 7) &^ 7 // round up to multiple of 8
if size > cb.remaining {
return syserror.EINVAL
}
@@ -106,7 +107,12 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error {
usermem.ByteOrder.PutUint16(buf[16:18], uint16(size))
buf[18] = dirent.Type
copy(buf[19:], dirent.Name)
- buf[size-1] = 0 // NUL terminator
+ // Zero out all remaining bytes in buf, including the NUL terminator
+ // after dirent.Name.
+ bufTail := buf[19+len(dirent.Name):]
+ for i := range bufTail {
+ bufTail[i] = 0
+ }
} else {
// struct linux_dirent {
// unsigned long d_ino; /* Inode number */
@@ -125,6 +131,7 @@ 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)
+ size = (size + 7) &^ 7 // round up to multiple of sizeof(long)
if size > cb.remaining {
return syserror.EINVAL
}
@@ -133,9 +140,14 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error {
usermem.ByteOrder.PutUint64(buf[8:16], uint64(dirent.NextOff))
usermem.ByteOrder.PutUint16(buf[16:18], uint16(size))
copy(buf[18:], dirent.Name)
- buf[size-3] = 0 // NUL terminator
- buf[size-2] = 0 // zero padding byte
- buf[size-1] = dirent.Type
+ // Zero out all remaining bytes in buf, including the NUL terminator
+ // after dirent.Name and the zero padding byte between the name and
+ // dirent type.
+ bufTail := buf[18+len(dirent.Name):]
+ for i := range bufTail {
+ bufTail[i] = 0
+ }
+ bufTail[2] = dirent.Type
}
n, err := cb.t.CopyOutBytes(cb.addr, buf)
if err != nil {