From: Eric Dumazet edumazet@google.com
stable inclusion from stable-v5.10.109 commit 163960a7de1333514c9352deb7c80c6b9fd9abf2 bugzilla: https://gitee.com/src-openeuler/kernel/issues/I51YBN CVE: CVE-2022-28356
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
commit 2d327a79ee176930dc72c131a970c891d367c1dc upstream.
My latest patch, attempting to fix the refcount leak in a minimal way turned out to add a new bug.
Whenever the bind operation fails before we attempt to grab a reference count on a device, we might release the device refcount of a prior successful bind() operation.
syzbot was not happy about this [1].
Note to stable teams:
Make sure commit b37a46683739 ("netdevice: add the case if dev is NULL") is already present in your trees.
[1] general protection fault, probably for non-canonical address 0xdffffc0000000070: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000380-0x0000000000000387] CPU: 1 PID: 3590 Comm: syz-executor361 Tainted: G W 5.17.0-syzkaller-04796-g169e77764adc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:llc_ui_connect+0x400/0xcb0 net/llc/af_llc.c:500 Code: 80 3c 02 00 0f 85 fc 07 00 00 4c 8b a5 38 05 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d bc 24 80 03 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 a9 07 00 00 49 8b b4 24 80 03 00 00 4c 89 f2 48 RSP: 0018:ffffc900038cfcc0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8880756eb600 RCX: 0000000000000000 RDX: 0000000000000070 RSI: ffffc900038cfe3e RDI: 0000000000000380 RBP: ffff888015ee5000 R08: 0000000000000001 R09: ffff888015ee5535 R10: ffffed1002bdcaa6 R11: 0000000000000000 R12: 0000000000000000 R13: ffffc900038cfe37 R14: ffffc900038cfe38 R15: ffff888015ee5012 FS: 0000555555acd300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000280 CR3: 0000000077db6000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __sys_connect_file+0x155/0x1a0 net/socket.c:1900 __sys_connect+0x161/0x190 net/socket.c:1917 __do_sys_connect net/socket.c:1927 [inline] __se_sys_connect net/socket.c:1924 [inline] __x64_sys_connect+0x6f/0xb0 net/socket.c:1924 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f016acb90b9 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd417947f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f016acb90b9 RDX: 0000000000000010 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 00007f016ac7d0a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f016ac7d130 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:llc_ui_connect+0x400/0xcb0 net/llc/af_llc.c:500
Fixes: 764f4eb6846f ("llc: fix netdevice reference leaks in llc_ui_bind()") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: 赵子轩 beraphin@gmail.com Cc: Stoyan Manolov smanolov@suse.de Link: https://lore.kernel.org/r/20220325035827.360418-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Signed-off-by: Huang Guobin huangguobin4@huawei.com Reviewed-by: Wei Yongjun weiyongjun1@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- net/llc/af_llc.c | 57 +++++++++++++++++++++++++++--------------------- 1 file changed, 32 insertions(+), 25 deletions(-)
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 2fdb72a26fa8..99a37c411323 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -276,6 +276,7 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr) { struct sock *sk = sock->sk; struct llc_sock *llc = llc_sk(sk); + struct net_device *dev = NULL; struct llc_sap *sap; int rc = -EINVAL;
@@ -287,14 +288,14 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr) goto out; rc = -ENODEV; if (sk->sk_bound_dev_if) { - llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if); - if (llc->dev && addr->sllc_arphrd != llc->dev->type) { - dev_put(llc->dev); - llc->dev = NULL; + dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if); + if (dev && addr->sllc_arphrd != dev->type) { + dev_put(dev); + dev = NULL; } } else - llc->dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd); - if (!llc->dev) + dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd); + if (!dev) goto out; rc = -EUSERS; llc->laddr.lsap = llc_ui_autoport(); @@ -304,6 +305,11 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr) sap = llc_sap_open(llc->laddr.lsap, NULL); if (!sap) goto out; + + /* Note: We do not expect errors from this point. */ + llc->dev = dev; + dev = NULL; + memcpy(llc->laddr.mac, llc->dev->dev_addr, IFHWADDRLEN); memcpy(&llc->addr, addr, sizeof(llc->addr)); /* assign new connection to its SAP */ @@ -311,10 +317,7 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr) sock_reset_flag(sk, SOCK_ZAPPED); rc = 0; out: - if (rc) { - dev_put(llc->dev); - llc->dev = NULL; - } + dev_put(dev); return rc; }
@@ -337,6 +340,7 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr; struct sock *sk = sock->sk; struct llc_sock *llc = llc_sk(sk); + struct net_device *dev = NULL; struct llc_sap *sap; int rc = -EINVAL;
@@ -352,25 +356,26 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) rc = -ENODEV; rcu_read_lock(); if (sk->sk_bound_dev_if) { - llc->dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if); - if (llc->dev) { + dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if); + if (dev) { if (is_zero_ether_addr(addr->sllc_mac)) - memcpy(addr->sllc_mac, llc->dev->dev_addr, + memcpy(addr->sllc_mac, dev->dev_addr, IFHWADDRLEN); - if (addr->sllc_arphrd != llc->dev->type || + if (addr->sllc_arphrd != dev->type || !ether_addr_equal(addr->sllc_mac, - llc->dev->dev_addr)) { + dev->dev_addr)) { rc = -EINVAL; - llc->dev = NULL; + dev = NULL; } } - } else - llc->dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd, + } else { + dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd, addr->sllc_mac); - if (llc->dev) - dev_hold(llc->dev); + } + if (dev) + dev_hold(dev); rcu_read_unlock(); - if (!llc->dev) + if (!dev) goto out; if (!addr->sllc_sap) { rc = -EUSERS; @@ -403,6 +408,11 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) goto out_put; } } + + /* Note: We do not expect errors from this point. */ + llc->dev = dev; + dev = NULL; + llc->laddr.lsap = addr->sllc_sap; memcpy(llc->laddr.mac, addr->sllc_mac, IFHWADDRLEN); memcpy(&llc->addr, addr, sizeof(llc->addr)); @@ -413,10 +423,7 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) out_put: llc_sap_put(sap); out: - if (rc) { - dev_put(llc->dev); - llc->dev = NULL; - } + dev_put(dev); release_sock(sk); return rc; }