Re: [PATCH v2] net: mac802154: Fix general protection fault

syzbot found general protection fault in crypto_destroy_tfm()[1].
It was caused by wrong clean up loop in llsec_key_alloc().
If one of the tfm array members is in IS_ERR() range it will
cause general protection fault in clean up function [1].

Call Trace:
  crypto_free_aead include/crypto/aead.h:191 [inline] [1]
  llsec_key_alloc net/mac802154/llsec.c:156 [inline]
  mac802154_llsec_key_add+0x9e0/0xcc0 net/mac802154/llsec.c:249
  ieee802154_add_llsec_key+0x56/0x80 net/mac802154/cfg.c:338
  rdev_add_llsec_key net/ieee802154/rdev-ops.h:260 [inline]
  nl802154_add_llsec_key+0x3d3/0x560 net/ieee802154/nl802154.c:1584
  genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739
  genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
  genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800
  netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502
  genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
  netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338
  netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927
  sock_sendmsg_nosec net/socket.c:654 [inline]
  sock_sendmsg+0xcf/0x120 net/socket.c:674
  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
  ___sys_sendmsg+0xf3/0x170 net/socket.c:2404
  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433
  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Signed-off-by: Pavel Skripkin <redacted>
Reported-by: syzbot+9ec037722d2603a9f52e@syzkaller.appspotmail.com
Change-Id: I29f7ac641a039096d63d1e6070bb32cb5a3beb07
---
  net/mac802154/llsec.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac802154/llsec.c b/net/mac802154/llsec.c
index 585d33144c33..55550ead2ced 100644
--- a/net/mac802154/llsec.c
+++ b/net/mac802154/llsec.c

@@ -152,7 +152,7 @@ llsec_key_alloc(const struct ieee802154_llsec_key *template)
  	crypto_free_sync_skcipher(key->tfm0);
  err_tfm:
  	for (i = 0; i < ARRAY_SIZE(key->tfm); i++)
-		if (key->tfm[i])
+		if (!IS_ERR_OR_NULL(key->tfm[i]))
  			crypto_free_aead(key->tfm[i]);
  
  	kfree_sensitive(key);