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authorCraig Gallek <kraig@google.com>2017-10-30 18:50:11 -0400
committerDavid S. Miller <davem@davemloft.net>2017-11-01 20:52:36 +0900
commit93161922c658c714715686cd0cf69b090cb9bf1d (patch)
tree2666a57c04802e3e42d61f14d08d31af73a85095
parentd70eaa386bf9ecc1e5b3002f64eb59172fcec4fd (diff)
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): [<ffffffff824b8381>] _raw_spin_unlock_irqrestore+0x31/0x75 hardirqs last disabled at (329692056): [<ffffffff824b9e58>] apic_timer_interrupt+0x98/0xb0 softirqs last enabled at (35659740): [<ffffffff824bc958>] __do_softirq+0x328/0x48c softirqs last disabled at (35659731): [<ffffffff811c796c>] 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 <kraig@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/tap.c2
-rw-r--r--drivers/net/tun.c4
2 files changed, 6 insertions, 0 deletions
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);