This is a note to let you know that I've just added the patch titled
integrity: Fix possible multiple allocation in integrity_inode_get()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
integrity-fix-possible-multiple-allocation-in-integrity_inode_get.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9df6a4870dc371136e90330cfbbc51464ee66993 Mon Sep 17 00:00:00 2001
From: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx>
Date: Thu, 1 Jun 2023 14:42:44 +0800
Subject: integrity: Fix possible multiple allocation in integrity_inode_get()
From: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx>
commit 9df6a4870dc371136e90330cfbbc51464ee66993 upstream.
When integrity_inode_get() is querying and inserting the cache, there
is a conditional race in the concurrent environment.
The race condition is the result of not properly implementing
"double-checked locking". In this case, it first checks to see if the
iint cache record exists before taking the lock, but doesn't check
again after taking the integrity_iint_lock.
Fixes: bf2276d10ce5 ("ima: allocating iint improvements")
Signed-off-by: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx>
Cc: Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v3.10+
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
security/integrity/iint.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -46,12 +46,10 @@ static struct integrity_iint_cache *__in
else if (inode > iint->inode)
n = n->rb_right;
else
- break;
+ return iint;
}
- if (!n)
- return NULL;
- return iint;
+ return NULL;
}
/*
@@ -116,10 +114,15 @@ struct integrity_iint_cache *integrity_i
parent = *p;
test_iint = rb_entry(parent, struct integrity_iint_cache,
rb_node);
- if (inode < test_iint->inode)
+ if (inode < test_iint->inode) {
p = &(*p)->rb_left;
- else
+ } else if (inode > test_iint->inode) {
p = &(*p)->rb_right;
+ } else {
+ write_unlock(&integrity_iint_lock);
+ kmem_cache_free(iint_cache, iint);
+ return test_iint;
+ }
}
iint->inode = inode;
Patches currently in stable-queue which might be from tianjia.zhang@xxxxxxxxxxxxxxxxx are
queue-4.19/integrity-fix-possible-multiple-allocation-in-integrity_inode_get.patch
