[PATCH 4.19 024/148] aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts

Sasha Levin
2024-03-24T23:50:41Z

From: Chun-Yi Lee <jlee@suse.com>

[ Upstream commit f98364e926626c678fb4b9004b75cacf92ff0662 ]

This patch is against CVE-2023-6270. The description of cve is:

A flaw was found in the ATA over Ethernet (AoE) driver in the Linux
kernel. The aoecmd_cfg_pkts() function improperly updates the refcnt on
`struct net_device`, and a use-after-free can be triggered by racing
between the free on the struct and the access through the `skbtxq`
global queue. This could lead to a denial of service condition or
potential code execution.

In aoecmd_cfg_pkts(), it always calls dev_put(ifp) when skb initial
code is finished. But the net_device ifp will still be used in
later tx()->dev_queue_xmit() in kthread. Which means that the
dev_put(ifp) should NOT be called in the success path of skb
initial code in aoecmd_cfg_pkts(). Otherwise tx() may run into
use-after-free because the net_device is freed.

This patch removed the dev_put(ifp) in the success path in
aoecmd_cfg_pkts(), and added dev_put() after skb xmit in tx().

Link: https://nvd.nist.gov/vuln/detail/CVE-2023-6270
Fixes: 7562f876cd93 ("[NET]: Rework dev_base via list_head (v3)")
Signed-off-by: Chun-Yi Lee <jlee@suse.com>
Link: https://lore.kernel.org/r/20240305082048.25526-1-jlee@suse.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/aoe/aoecmd.c | 12 ++++++------
drivers/block/aoe/aoenet.c | 1 +
2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 136dc507d0206..c2b32c53da2bb 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -420,13 +420,16 @@ aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff_head *qu
rcu_read_lock();
for_each_netdev_rcu(&init_net, ifp) {
dev_hold(ifp);
- if (!is_aoe_netif(ifp))
- goto cont;
+ if (!is_aoe_netif(ifp)) {
+ dev_put(ifp);
+ continue;
+ }

skb = new_skb(sizeof *h + sizeof *ch);
if (skb == NULL) {
printk(KERN_INFO "aoe: skb alloc failure\n");
- goto cont;
+ dev_put(ifp);
+ continue;
}
skb_put(skb, sizeof *h + sizeof *ch);
skb->dev = ifp;
@@ -441,9 +444,6 @@ aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff_head *qu
h->major = cpu_to_be16(aoemajor);
h->minor = aoeminor;
h->cmd = AOECMD_CFG;
-
-cont:
- dev_put(ifp);
}
rcu_read_unlock();
}
diff --git a/drivers/block/aoe/aoenet.c b/drivers/block/aoe/aoenet.c
index 63773a90581dd..1e66c7a188a12 100644
--- a/drivers/block/aoe/aoenet.c
+++ b/drivers/block/aoe/aoenet.c
@@ -64,6 +64,7 @@ tx(int id) __must_hold(&txlock)
pr_warn("aoe: packet could not be sent on %s. %s\n",
ifp ? ifp->name : "netif",
"consider increasing tx_queue_len");
+ dev_put(ifp);
spin_lock_irq(&txlock);
}
return 0;
--
2.43.0