linux-kernel - [PATCH] fs: prevent use after free in auditing when symlink following was denied

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Date:	Thu,  4 Oct 2012 19:56:40 -0400
From:	Sasha Levin <sasha.levin@...cle.com>
To:	viro@...iv.linux.org.uk, keescook@...omium.org
Cc:	levinsasha928@...il.com, davej@...hat.com,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Sasha Levin <sasha.levin@...cle.com>
Subject: [PATCH] fs: prevent use after free in auditing when symlink following was denied

Commit "fs: add link restriction audit reporting" has added auditing of failed
attempts to follow symlinks. Unfortunately, the auditing was being done after
the struct path structure was released earlier.

Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
---
 fs/namei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index aa30d19..6d47fac 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -692,9 +692,9 @@ static inline int may_follow_link(struct path *link, struct nameidata *nd)
 	if (uid_eq(parent->i_uid, inode->i_uid))
 		return 0;
 
+	audit_log_link_denied("follow_link", link);
 	path_put_conditional(link, nd);
 	path_put(&nd->path);
-	audit_log_link_denied("follow_link", link);
 	return -EACCES;
 }
 
-- 
1.7.12

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