| Message ID | 149324135581.24512.17200609423997054366.stgit@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Apr 26, 2017 at 2:15 PM, David Howells <dhowells@redhat.com> wrote:
> [!] NOTE: This breaks UAPI introduced in 4.11-rc1.
Ugh.
I'm, applying this now, so that we don't end up with a released kernel
that supports the NULL filename thing.
I'm not happy about the timing though. And I hope nobody started using
statx() outside of tests.
Linus
--
To unsubscribe from this list: send the line "unsubscribe fstests" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
On 27 April 2017 at 00:03, Linus Torvalds <torvalds@linux-foundation.org> wrote: > On Wed, Apr 26, 2017 at 2:15 PM, David Howells <dhowells@redhat.com> wrote: >> [!] NOTE: This breaks UAPI introduced in 4.11-rc1. > > Ugh. > > I'm, applying this now, so that we don't end up with a released kernel > that supports the NULL filename thing. > > I'm not happy about the timing though. And I hope nobody started using > statx() outside of tests. Agreed on the timing. Late review on my part didn't help. But, also, David's fix is not quite right. I will send a patch. Cheers, Michael
diff --git a/fs/stat.c b/fs/stat.c index c6c963b2546b..3d85747bd86e 100644 --- a/fs/stat.c +++ b/fs/stat.c @@ -547,13 +547,13 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) /** * sys_statx - System call to get enhanced stats * @dfd: Base directory to pathwalk from *or* fd to stat. - * @filename: File to stat *or* NULL. + * @filename: File to stat or "" with AT_EMPTY_PATH * @flags: AT_* flags to control pathwalk. * @mask: Parts of statx struct actually required. * @buffer: Result buffer. * - * Note that if filename is NULL, then it does the equivalent of fstat() using - * dfd to indicate the file of interest. + * Note that fstat() can be emulated by setting dfd to the fd of interest, + * supplying "" as the filename and setting AT_EMPTY_PATH in the flags. */ SYSCALL_DEFINE5(statx, int, dfd, const char __user *, filename, unsigned, flags, @@ -567,11 +567,10 @@ SYSCALL_DEFINE5(statx, return -EINVAL; if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE) return -EINVAL; + if (!filename) + return -EINVAL; - if (filename) - error = vfs_statx(dfd, filename, flags, &stat, mask); - else - error = vfs_statx_fd(dfd, &stat, mask, flags); + error = vfs_statx(dfd, filename, flags, &stat, mask); if (error) return error;
[!] NOTE: This breaks UAPI introduced in 4.11-rc1. With the new statx() syscall, the following both allow the attributes of the file attached to a file descriptor to be retrieved: statx(dfd, NULL, 0, ...); and: statx(dfd, "", AT_EMPTY_PATH, ...); Change the code to reject the first option, though this means copying the path and engaging pathwalk for the fstat() equivalent. dfd can be a non-directory provided path is "". Fixes: a528d35e8bfc ("statx: Add a system call to make enhanced file info available") Reported-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Eric Sandeen <sandeen@sandeen.net> cc: fstests@vger.kernel.org cc: linux-api@vger.kernel.org cc: linux-man@vger.kernel.org --- fs/stat.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html