Messages in this thread Patch in this message | | | From | Qian Cai <> | Subject | [PATCH] signal: allow the null signal in rt_sigqueueinfo() | Date | Sat, 5 Jan 2019 00:47:29 -0500 |
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Running the trinity fuzzer triggered this,
UBSAN: Undefined behaviour in kernel/signal.c:2946:7 shift exponent 4294967295 is too large for 64-bit type 'long unsigned int' [ 3752.406618] dump_stack+0xe0/0x17a [ 3752.419817] ubsan_epilogue+0xd/0x4e [ 3752.423429] __ubsan_handle_shift_out_of_bounds+0x1d6/0x227 [ 3752.447269] known_siginfo_layout.cold.9+0x16/0x1b [ 3752.452105] __copy_siginfo_from_user+0x4b/0x70 [ 3752.466620] do_syscall_64+0x164/0x7ea [ 3752.565030] entry_SYSCALL_64_after_hwframe+0x49/0xbe
This is because signo is 0 from userspace, and then it ends up calling (1UL << -1) in sig_specific_sicodes(). Since the null signal (0) is allowed in the spec, just deal with it accordingly.
Signed-off-by: Qian Cai <cai@lca.pw> --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/signal.c b/kernel/signal.c index e1d7ad8e6ab1..970bb36837a9 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2943,7 +2943,7 @@ static bool known_siginfo_layout(unsigned sig, int si_code) if (si_code == SI_KERNEL) return true; else if ((si_code > SI_USER)) { - if (sig_specific_sicodes(sig)) { + if (sig && sig_specific_sicodes(sig)) { if (si_code <= sig_sicodes[sig].limit) return true; } -- 2.17.2 (Apple Git-113)
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