Commit 9ecd5948 authored by Al Viro's avatar Al Viro Committed by Luis Henriques

do_last(): don't let a bogus return value from ->open() et.al. to confuse us

commit c80567c8 upstream.

... into returning a positive to path_openat(), which would interpret that
as "symlink had been encountered" and proceed to corrupt memory, etc.
It can only happen due to a bug in some ->open() instance or in some LSM
hook, etc., so we report any such event *and* make sure it doesn't trick
us into further unpleasantness.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent e59c6daf
...@@ -3108,6 +3108,10 @@ static int do_last(struct nameidata *nd, struct path *path, ...@@ -3108,6 +3108,10 @@ static int do_last(struct nameidata *nd, struct path *path,
goto exit_fput; goto exit_fput;
} }
out: out:
if (unlikely(error > 0)) {
WARN_ON(1);
error = -EINVAL;
}
if (got_write) if (got_write)
mnt_drop_write(nd->path.mnt); mnt_drop_write(nd->path.mnt);
path_put(&save_parent); path_put(&save_parent);
......
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