From 0ad646c81b2182f7fa67ec0c8c825e0ee165696d Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Fri, 13 Oct 2017 11:58:53 -0700 Subject: tun: call dev_get_valid_name() before register_netdevice() register_netdevice() could fail early when we have an invalid dev name, in which case ->ndo_uninit() is not called. For tun device, this is a problem because a timer etc. are already initialized and it expects ->ndo_uninit() to clean them up. We could move these initializations into a ->ndo_init() so that register_netdevice() knows better, however this is still complicated due to the logic in tun_detach(). Therefore, I choose to just call dev_get_valid_name() before register_netdevice(), which is quicker and much easier to audit. And for this specific case, it is already enough. Fixes: 96442e42429e ("tuntap: choose the txq based on rxq") Reported-by: Dmitry Alexeev Cc: Jason Wang Cc: "Michael S. Tsirkin" Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 5ce580f413b9..e21bf90b819f 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2027,6 +2027,9 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) if (!dev) return -ENOMEM; + err = dev_get_valid_name(net, dev, name); + if (err) + goto err_free_dev; dev_net_set(dev, net); dev->rtnl_link_ops = &tun_link_ops; -- cgit v1.2.3 From 5c25f65fd1e42685f7ccd80e0621829c105785d9 Mon Sep 17 00:00:00 2001 From: Julien Gomes Date: Wed, 25 Oct 2017 11:50:50 -0700 Subject: tun: allow positive return values on dev_get_valid_name() call If the name argument of dev_get_valid_name() contains "%d", it will try to assign it a unit number in __dev__alloc_name() and return either the unit number (>= 0) or an error code (< 0). Considering positive values as error values prevent tun device creations relying this mechanism, therefor we should only consider negative values as errors here. Signed-off-by: Julien Gomes Acked-by: Cong Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index e21bf90b819f..b9973fb868b7 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2028,7 +2028,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) if (!dev) return -ENOMEM; err = dev_get_valid_name(net, dev, name); - if (err) + if (err < 0) goto err_free_dev; dev_net_set(dev, net); -- cgit v1.2.3 From 63b9ab65bd76e5de6479bb14b4014b64aa1a317a Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Fri, 27 Oct 2017 11:05:44 +0800 Subject: tuntap: properly align skb->head before building skb An unaligned alloc_frag->offset caused by previous allocation will result an unaligned skb->head. This will lead unaligned skb_shared_info and then unaligned dataref which requires to be aligned for accessing on some architecture. Fix this by aligning alloc_frag->offset before the frag refilling. Fixes: 0bbd7dad34f8 ("tun: make tun_build_skb() thread safe") Cc: Eric Dumazet Cc: Willem de Bruijn Cc: Wei Wei Cc: Dmitry Vyukov Cc: Mark Rutland Reported-by: Wei Wei Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index b9973fb868b7..5550f56cb895 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1286,6 +1286,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, buflen += SKB_DATA_ALIGN(len + pad); rcu_read_unlock(); + alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES); if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL))) return ERR_PTR(-ENOMEM); -- cgit v1.2.3 From 93161922c658c714715686cd0cf69b090cb9bf1d Mon Sep 17 00:00:00 2001 From: Craig Gallek Date: Mon, 30 Oct 2017 18:50:11 -0400 Subject: tun/tap: sanitize TUNSETSNDBUF input Syzkaller found several variants of the lockup below by setting negative values with the TUNSETSNDBUF ioctl. This patch adds a sanity check to both the tun and tap versions of this ioctl. watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [repro:2389] Modules linked in: irq event stamp: 329692056 hardirqs last enabled at (329692055): [] _raw_spin_unlock_irqrestore+0x31/0x75 hardirqs last disabled at (329692056): [] apic_timer_interrupt+0x98/0xb0 softirqs last enabled at (35659740): [] __do_softirq+0x328/0x48c softirqs last disabled at (35659731): [] irq_exit+0xbc/0xd0 CPU: 0 PID: 2389 Comm: repro Not tainted 4.14.0-rc7 #23 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff880009452140 task.stack: ffff880006a20000 RIP: 0010:_raw_spin_lock_irqsave+0x11/0x80 RSP: 0018:ffff880006a27c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10 RAX: ffff880009ac68d0 RBX: ffff880006a27ce0 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffff880006a27ce0 RDI: ffff880009ac6900 RBP: ffff880006a27c60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 000000000063ff00 R12: ffff880009ac6900 R13: ffff880006a27cf8 R14: 0000000000000001 R15: ffff880006a27cf8 FS: 00007f4be4838700(0000) GS:ffff88000cc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020101000 CR3: 0000000009616000 CR4: 00000000000006f0 Call Trace: prepare_to_wait+0x26/0xc0 sock_alloc_send_pskb+0x14e/0x270 ? remove_wait_queue+0x60/0x60 tun_get_user+0x2cc/0x19d0 ? __tun_get+0x60/0x1b0 tun_chr_write_iter+0x57/0x86 __vfs_write+0x156/0x1e0 vfs_write+0xf7/0x230 SyS_write+0x57/0xd0 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x7f4be4356df9 RSP: 002b:00007ffc18101c08 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4be4356df9 RDX: 0000000000000046 RSI: 0000000020101000 RDI: 0000000000000005 RBP: 00007ffc18101c40 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000293 R12: 0000559c75f64780 R13: 00007ffc18101d30 R14: 0000000000000000 R15: 0000000000000000 Fixes: 33dccbb050bb ("tun: Limit amount of queued packets per device") Fixes: 20d29d7a916a ("net: macvtap driver") Signed-off-by: Craig Gallek Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- drivers/net/tap.c | 2 ++ drivers/net/tun.c | 4 ++++ 2 files changed, 6 insertions(+) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 1b10fcc6a58d..6c0c84c33e1f 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -1032,6 +1032,8 @@ static long tap_ioctl(struct file *file, unsigned int cmd, case TUNSETSNDBUF: if (get_user(s, sp)) return -EFAULT; + if (s <= 0) + return -EINVAL; q->sk.sk_sndbuf = s; return 0; diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 5550f56cb895..42bb820a56c9 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2429,6 +2429,10 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = -EFAULT; break; } + if (sndbuf <= 0) { + ret = -EINVAL; + break; + } tun->sndbuf = sndbuf; tun_set_sndbuf(tun); -- cgit v1.2.3