netdev - [net v1] devlink: fix xa_alloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250214132453.4108-1-michal.swiatkowski@linux.intel.com>
Date: Fri, 14 Feb 2025 14:24:53 +0100
From: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
To: netdev@...r.kernel.org
Cc: jiri@...nulli.us,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	horms@...nel.org,
	pierre@...ckhpc.com,
	Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
Subject: [net v1] devlink: fix xa_alloc_cyclic error handling

Pierre Riteau <pierre@...ckhpc.com> found suspicious handling an error
from xa_alloc_cyclic() in scheduler code [1]. The same is done in
devlink_rel_alloc().

In case of returning 1 from xa_alloc_cyclic() (wrapping) ERR_PTR(1) will
be returned, which will cause IS_ERR() to be false. Which can lead to
dereference not allocated pointer (rel).

Fix it by checking if err is lower than zero.

This wasn't found in real usecase, only noticed. Credit to Pierre.

Signed-off-by: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
---
 net/devlink/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/devlink/core.c b/net/devlink/core.c
index f49cd83f1955..7203c39532fc 100644
--- a/net/devlink/core.c
+++ b/net/devlink/core.c
@@ -117,7 +117,7 @@ static struct devlink_rel *devlink_rel_alloc(void)

 	err = xa_alloc_cyclic(&devlink_rels, &rel->index, rel,
 			      xa_limit_32b, &next, GFP_KERNEL);
-	if (err) {
+	if (err < 0) {
 		kfree(rel);
 		return ERR_PTR(err);
 	}
-- 
2.42.0