autofs_expire_run() calls dput(dentry) to drop the reference count of
dentry. However, dentry is read via autofs_dentry_ino(dentry) after
that. This may result in a use-free-bug. The patch drops the reference
count of dentry only when it is never used.
Link: http://lkml.kernel.org/r/154725122396.11260.16053424107144453867.stgit@pluto-themaw-net
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pkt.len = dentry->d_name.len;
memcpy(pkt.name, dentry->d_name.name, pkt.len);
pkt.name[pkt.len] = '\0';
- dput(dentry);
if (copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)))
ret = -EFAULT;
complete_all(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
+ dput(dentry);
+
return ret;
}