dump_common_audit_data(): fix racy accesses to ->d_name

commit d36a1dd9f77ae1e72da48f4123ed35627848507d upstream.

We are not guaranteed the locking environment that would prevent
dentry getting renamed right under us.  And it's possible for
old long name to be freed after rename, leading to UAF here.

Cc: stable@kernel.org # v2.6.2+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Al Viro 2021-01-05 14:43:46 -05:00 committed by Greg Kroah-Hartman
parent 09b3e0bc8e
commit a3fddad7af

View File

@ -278,7 +278,9 @@ static void dump_common_audit_data(struct audit_buffer *ab,
struct inode *inode;
audit_log_format(ab, " name=");
spin_lock(&a->u.dentry->d_lock);
audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
spin_unlock(&a->u.dentry->d_lock);
inode = d_backing_inode(a->u.dentry);
if (inode) {
@ -297,8 +299,9 @@ static void dump_common_audit_data(struct audit_buffer *ab,
dentry = d_find_alias(inode);
if (dentry) {
audit_log_format(ab, " name=");
audit_log_untrustedstring(ab,
dentry->d_name.name);
spin_lock(&dentry->d_lock);
audit_log_untrustedstring(ab, dentry->d_name.name);
spin_unlock(&dentry->d_lock);
dput(dentry);
}
audit_log_format(ab, " dev=");