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dump_common_audit_data(): fix racy accesses to ->d_name

commit d36a1dd9f7 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>
5.4-rM2-2.2.x-imx-squashed
Al Viro 2021-01-05 14:43:46 -05:00 committed by Greg Kroah-Hartman
parent d443cefd9f
commit 08eb8a735c
1 changed files with 5 additions and 2 deletions

View File

@ -274,7 +274,9 @@ 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) {
@ -292,8 +294,9 @@ 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=");