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authorEric Biggers <ebiggers@google.com>2017-03-31 20:31:32 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2017-04-03 08:05:56 +0300
commit8c7493aa3e9ae90f90196f4d4c1398ad143cba7b (patch)
tree1639352862be76cb08c7b04f64a71008aeab18b9 /fs/stat.c
parent75dd7e4bb663c7047c7d1bd4dad26f8c048851be (diff)
downloadlinux-8c7493aa3e9ae90f90196f4d4c1398ad143cba7b.tar.xz
statx: reject unknown flags when using NULL path
The statx() system call currently accepts unknown flags when called with a NULL path to operate on a file descriptor. Left unchanged, this could make it hard to introduce new query flags in the future, since applications may not be able to tell whether a given flag is supported. Fix this by failing the system call with EINVAL if any flags other than KSTAT_QUERY_FLAGS are specified in combination with a NULL path. Arguably, we could still permit known lookup-related flags such as AT_SYMLINK_NOFOLLOW. However, that would be inconsistent with how sys_utimensat() behaves when passed a NULL path, which seems to be the closest precedent. And given that the NULL path case is (I believe) mainly intended to be used to implement a wrapper function like fstatx() that doesn't have a path argument, I think rejecting lookup-related flags too is probably the best choice. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/stat.c')
-rw-r--r--fs/stat.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/stat.c b/fs/stat.c
index fa0be59340cc..df484a60846d 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -130,9 +130,13 @@ EXPORT_SYMBOL(vfs_getattr);
int vfs_statx_fd(unsigned int fd, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
- struct fd f = fdget_raw(fd);
+ struct fd f;
int error = -EBADF;
+ if (query_flags & ~KSTAT_QUERY_FLAGS)
+ return -EINVAL;
+
+ f = fdget_raw(fd);
if (f.file) {
error = vfs_getattr(&f.file->f_path, stat,
request_mask, query_flags);