aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts

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>

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index d7317425be510d1c3d4bbac5a18fba2ea8e76c1d..cc9077b588d7e7af30401ab03c826a358b2a232c 100644 (file)
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -419,13 +419,16 @@ 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;
@@ -440,9 +443,6 @@ 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 c51ea95bc2ce41f6260302f5efe914d3e12e1d98..923a134fd766562fcf9d33a993739040517258c1 100644 (file)
--- a/drivers/block/aoe/aoenet.c
+++ b/drivers/block/aoe/aoenet.c
@@ -63,6 +63,7 @@ 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;