From a3fddad7af2cd1c60d1ea639a94e7d63c693cd23 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 5 Jan 2021 14:43:46 -0500 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- security/lsm_audit.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/security/lsm_audit.c b/security/lsm_audit.c index 53d0d183db8f..08d5ef49f2e4 100644 --- a/security/lsm_audit.c +++ b/security/lsm_audit.c @@ -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=");