[PATCH v2] signal: Avoid undefined behaviour in kill_something_info
From: zhongjiang
Date: Mon Jun 05 2017 - 08:58:53 EST
when I run the kill(72057458746458112, 0) in the userspace, I hit
the following issue.
[ 304.606353] UBSAN: Undefined behaviour in kernel/signal.c:1462:11
[ 304.612622] negation of -2147483648 cannot be represented in type 'int':
[ 304.619516] CPU: 226 PID: 9849 Comm: test Tainted: G B ---- ------- 3.10.0-327.53.58.70.x86_64_ubsan+ #116
[ 304.630692] Hardware name: Huawei Technologies Co., Ltd. RH8100 V3/BC61PBIA, BIOS BLHSV028 11/11/2014
[ 304.640168] ffffffff825ded30 000000005dc276fa ffff883c3a4b7ce0 ffffffff81d6eb06
[ 304.647870] ffff883c3a4b7cf8 ffffffff81d6ebb9 ffffffff825ded20 ffff883c3a4b7de8
[ 304.655584] ffffffff81d6fc89 0000000041b58ab3 ffffffff8228d6d8 ffffffff81d6fb80
[ 304.663299] Call Trace:
[ 304.665827] [<ffffffff81d6eb06>] dump_stack+0x19/0x1b
[ 304.671115] [<ffffffff81d6ebb9>] ubsan_epilogue+0xd/0x50
[ 304.676668] [<ffffffff81d6fc89>] __ubsan_handle_negate_overflow+0x109/0x14e
[ 304.683917] [<ffffffff81d6fb80>] ? __ubsan_handle_divrem_overflow+0x1df/0x1df
[ 304.691353] [<ffffffff8134a129>] ? __inc_zone_state+0x29/0xf0
[ 304.697358] [<ffffffff813272df>] ? __lru_cache_add+0x8f/0xe0
[ 304.703272] [<ffffffff8132764e>] ? lru_cache_add+0xe/0x10
[ 304.708921] [<ffffffff812263bd>] ? map_id_up+0xad/0xe0
[ 304.714306] [<ffffffff8113126e>] SYSC_kill+0x43e/0x4d0
[ 304.725359] [<ffffffff8116e630>] ? lg_local_unlock+0x20/0xd0
[ 304.736978] [<ffffffff81130e30>] ? kill_pid+0x20/0x20
[ 304.747928] [<ffffffff81366f90>] ? __pmd_alloc+0x180/0x180
[ 304.759273] [<ffffffff8143f80b>] ? mntput+0x3b/0x70
[ 304.769919] [<ffffffff81d85c3c>] ? __do_page_fault+0x2bc/0x650
[ 304.781462] [<ffffffff8123bb47>] ? __audit_syscall_entry+0x1f7/0x2a0
[ 304.793476] [<ffffffff8113535e>] SyS_kill+0xe/0x10
[ 304.803859] [<ffffffff81d91109>] system_call_fastpath+0x16/0x1b
The patch add particular case to avoid the UBSAN detection.
Signed-off-by: zhongjiang <zhongjiang@xxxxxxxxxx>
---
kernel/signal.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/signal.c b/kernel/signal.c
index ca92bcf..63148f7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1395,6 +1395,12 @@ static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
read_lock(&tasklist_lock);
if (pid != -1) {
+ /*
+ * -INT_MIN is undefined, it need to exclude following case to
+ * avoid the UBSAN detection.
+ */
+ if (pid == INT_MIN)
+ return -ESRCH;
ret = __kill_pgrp_info(sig, info,
pid ? find_vpid(-pid) : task_pgrp(current));
} else {
--
1.7.12.4