From: YueHaibing yuehaibing@huawei.com
[ Upstream commit b805d78d300bcf2c83d6df7da0c818b0fee41427 ]
UBSAN report this:
UBSAN: Undefined behaviour in net/xfrm/xfrm_policy.c:1289:24 index 6 is out of range for type 'unsigned int [6]' CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.162-514.55.6.9.x86_64+ #13 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 0000000000000000 1466cf39b41b23c9 ffff8801f6b07a58 ffffffff81cb35f4 0000000041b58ab3 ffffffff83230f9c ffffffff81cb34e0 ffff8801f6b07a80 ffff8801f6b07a20 1466cf39b41b23c9 ffffffff851706e0 ffff8801f6b07ae8 Call Trace: <IRQ> [<ffffffff81cb35f4>] __dump_stack lib/dump_stack.c:15 [inline] <IRQ> [<ffffffff81cb35f4>] dump_stack+0x114/0x1a0 lib/dump_stack.c:51 [<ffffffff81d94225>] ubsan_epilogue+0x12/0x8f lib/ubsan.c:164 [<ffffffff81d954db>] __ubsan_handle_out_of_bounds+0x16e/0x1b2 lib/ubsan.c:382 [<ffffffff82a25acd>] __xfrm_policy_unlink+0x3dd/0x5b0 net/xfrm/xfrm_policy.c:1289 [<ffffffff82a2e572>] xfrm_policy_delete+0x52/0xb0 net/xfrm/xfrm_policy.c:1309 [<ffffffff82a3319b>] xfrm_policy_timer+0x30b/0x590 net/xfrm/xfrm_policy.c:243 [<ffffffff813d3927>] call_timer_fn+0x237/0x990 kernel/time/timer.c:1144 [<ffffffff813d8e7e>] __run_timers kernel/time/timer.c:1218 [inline] [<ffffffff813d8e7e>] run_timer_softirq+0x6ce/0xb80 kernel/time/timer.c:1401 [<ffffffff8120d6f9>] __do_softirq+0x299/0xe10 kernel/softirq.c:273 [<ffffffff8120e676>] invoke_softirq kernel/softirq.c:350 [inline] [<ffffffff8120e676>] irq_exit+0x216/0x2c0 kernel/softirq.c:391 [<ffffffff82c5edab>] exiting_irq arch/x86/include/asm/apic.h:652 [inline] [<ffffffff82c5edab>] smp_apic_timer_interrupt+0x8b/0xc0 arch/x86/kernel/apic/apic.c:926 [<ffffffff82c5c985>] apic_timer_interrupt+0xa5/0xb0 arch/x86/entry/entry_64.S:735 <EOI> [<ffffffff81188096>] ? native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:52 [<ffffffff810834d7>] arch_safe_halt arch/x86/include/asm/paravirt.h:111 [inline] [<ffffffff810834d7>] default_idle+0x27/0x430 arch/x86/kernel/process.c:446 [<ffffffff81085f05>] arch_cpu_idle+0x15/0x20 arch/x86/kernel/process.c:437 [<ffffffff8132abc3>] default_idle_call+0x53/0x90 kernel/sched/idle.c:92 [<ffffffff8132b32d>] cpuidle_idle_call kernel/sched/idle.c:156 [inline] [<ffffffff8132b32d>] cpu_idle_loop kernel/sched/idle.c:251 [inline] [<ffffffff8132b32d>] cpu_startup_entry+0x60d/0x9a0 kernel/sched/idle.c:299 [<ffffffff8113e119>] start_secondary+0x3c9/0x560 arch/x86/kernel/smpboot.c:245
The issue is triggered as this:
xfrm_add_policy -->verify_newpolicy_info //check the index provided by user with XFRM_POLICY_MAX //In my case, the index is 0x6E6BB6, so it pass the check. -->xfrm_policy_construct //copy the user's policy and set xfrm_policy_timer -->xfrm_policy_insert --> __xfrm_policy_link //use the orgin dir, in my case is 2 --> xfrm_gen_index //generate policy index, there is 0x6E6BB6
then xfrm_policy_timer be fired
xfrm_policy_timer --> xfrm_policy_id2dir //get dir from (policy index & 7), in my case is 6 --> xfrm_policy_delete --> __xfrm_policy_unlink //access policy_count[dir], trigger out of range access
Add xfrm_policy_id2dir check in verify_newpolicy_info, make sure the computed dir is valid, to fix the issue.
Reported-by: Hulk Robot hulkci@huawei.com Fixes: e682adf021be ("xfrm: Try to honor policy index if it's supplied by user") Signed-off-by: YueHaibing yuehaibing@huawei.com Acked-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/xfrm/xfrm_user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 9ff9255d2191b..919b8406028cc 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -1381,7 +1381,7 @@ static int verify_newpolicy_info(struct xfrm_userpolicy_info *p) ret = verify_policy_dir(p->dir); if (ret) return ret; - if (p->index && ((p->index & XFRM_POLICY_MAX) != p->dir)) + if (p->index && (xfrm_policy_id2dir(p->index) != p->dir)) return -EINVAL;
return 0;