From: Al Viro Date: Tue, 5 Jan 2021 19:43:46 +0000 (-0500) Subject: dump_common_audit_data(): fix racy accesses to ->d_name X-Git-Tag: v5.10.17~803 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a3fddad7af2cd1c60d1ea639a94e7d63c693cd23;p=platform%2Fkernel%2Flinux-rpi.git 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 --- diff --git a/security/lsm_audit.c b/security/lsm_audit.c index 53d0d18..08d5ef4 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=");