From fe53985aaac83d516b38358d4f39921d9942a0e2 Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Thu, 3 Dec 2015 16:49:32 +0100 Subject: [PATCH] pppoe: fix memory corruption in padt work structure pppoe_connect() mustn't touch the padt_work field of pppoe sockets because that work could be already pending. [ 21.473147] BUG: unable to handle kernel NULL pointer dereference at 00000004 [ 21.474523] IP: [] process_one_work+0x29/0x31c [ 21.475164] *pde = 00000000 [ 21.475513] Oops: 0000 [#1] SMP [ 21.475910] Modules linked in: pppoe pppox ppp_generic slhc crc32c_intel aesni_intel virtio_net xts aes_i586 lrw gf128mul ablk_helper cryptd evdev acpi_cpufreq processor serio_raw button ext4 crc16 mbcache jbd2 virtio_blk virtio_pci virtio_ring virtio [ 21.476168] CPU: 2 PID: 164 Comm: kworker/2:2 Not tainted 4.4.0-rc1 #1 [ 21.476168] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 21.476168] task: f5f83c00 ti: f5e28000 task.ti: f5e28000 [ 21.476168] EIP: 0060:[] EFLAGS: 00010046 CPU: 2 [ 21.476168] EIP is at process_one_work+0x29/0x31c [ 21.484082] EAX: 00000000 EBX: f678b2a0 ECX: 00000004 EDX: 00000000 [ 21.484082] ESI: f6c69940 EDI: f5e29ef0 EBP: f5e29f0c ESP: f5e29edc [ 21.484082] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 [ 21.484082] CR0: 80050033 CR2: 000000a4 CR3: 317ad000 CR4: 00040690 [ 21.484082] Stack: [ 21.484082] 00000000 f6c69950 00000000 f6c69940 c0042338 f5e29f0c c1327945 00000000 [ 21.484082] 00000008 f678b2a0 f6c69940 f678b2b8 f5e29f30 c1043984 f5f83c00 f6c69970 [ 21.484082] f678b2a0 c10437d3 f6775e80 f678b2a0 c10437d3 f5e29fac c1047059 f5e29f74 [ 21.484082] Call Trace: [ 21.484082] [] ? _raw_spin_lock_irq+0x28/0x30 [ 21.484082] [] worker_thread+0x1b1/0x244 [ 21.484082] [] ? rescuer_thread+0x229/0x229 [ 21.484082] [] ? rescuer_thread+0x229/0x229 [ 21.484082] [] kthread+0x8f/0x94 [ 21.484082] [] ? _raw_spin_unlock_irq+0x22/0x26 [ 21.484082] [] ret_from_kernel_thread+0x21/0x38 [ 21.484082] [] ? kthread_parkme+0x19/0x19 [ 21.496082] Code: 5d c3 55 89 e5 57 56 53 89 c3 83 ec 24 89 d0 89 55 e0 8d 7d e4 e8 6c d8 ff ff b9 04 00 00 00 89 45 d8 8b 43 24 89 45 dc 8b 45 d8 <8b> 40 04 8b 80 e0 00 00 00 c1 e8 05 24 01 88 45 d7 8b 45 e0 8d [ 21.496082] EIP: [] process_one_work+0x29/0x31c SS:ESP 0068:f5e29edc [ 21.496082] CR2: 0000000000000004 [ 21.496082] ---[ end trace e362cc9cf10dae89 ]--- Reported-by: Andrew Fixes: 287f3a943fef ("pppoe: Use workqueue to die properly when a PADT is received") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller --- drivers/net/ppp/pppoe.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c index 5e0b43283bce..0a37f840fcc5 100644 --- a/drivers/net/ppp/pppoe.c +++ b/drivers/net/ppp/pppoe.c @@ -568,6 +568,9 @@ static int pppoe_create(struct net *net, struct socket *sock, int kern) sk->sk_family = PF_PPPOX; sk->sk_protocol = PX_PROTO_OE; + INIT_WORK(&pppox_sk(sk)->proto.pppoe.padt_work, + pppoe_unbind_sock_work); + return 0; } @@ -632,8 +635,6 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr, lock_sock(sk); - INIT_WORK(&po->proto.pppoe.padt_work, pppoe_unbind_sock_work); - error = -EINVAL; if (sp->sa_protocol != PX_PROTO_OE) goto end; @@ -663,8 +664,13 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr, po->pppoe_dev = NULL; } - memset(sk_pppox(po) + 1, 0, - sizeof(struct pppox_sock) - sizeof(struct sock)); + po->pppoe_ifindex = 0; + memset(&po->pppoe_pa, 0, sizeof(po->pppoe_pa)); + memset(&po->pppoe_relay, 0, sizeof(po->pppoe_relay)); + memset(&po->chan, 0, sizeof(po->chan)); + po->next = NULL; + po->num = 0; + sk->sk_state = PPPOX_NONE; } -- 2.20.1