| From e4c6a7c96c38a71a2aed672ebe29cae125d907a1 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 19 Jul 2018 20:48:30 -0500 |
| Subject: signal: Properly deliver SIGSEGV from x86 uprobes |
| |
| From: Eric W. Biederman <ebiederm@xmission.com> |
| |
| [ Upstream commit 4a63c1ffd384ebdce40aac9c997dab68379137be ] |
| |
| For userspace to tell the difference between an random signal |
| and an exception, the exception must include siginfo information. |
| |
| Using SEND_SIG_FORCED for SIGSEGV is thus wrong, and it will result in |
| userspace seeing si_code == SI_USER (like a random signal) instead of |
| si_code == SI_KERNEL or a more specific si_code as all exceptions |
| deliver. |
| |
| Therefore replace force_sig_info(SIGSEGV, SEND_SIG_FORCE, current) |
| with force_sig(SIG_SEGV, current) which gets this right and is shorter |
| and easier to type. |
| |
| Fixes: 791eca10107f ("uretprobes/x86: Hijack return address") |
| Reviewed-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/x86/kernel/uprobes.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c |
| index 9119859ba7871..420aa7d3a2e6b 100644 |
| --- a/arch/x86/kernel/uprobes.c |
| +++ b/arch/x86/kernel/uprobes.c |
| @@ -1089,7 +1089,7 @@ arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs |
| pr_err("return address clobbered: pid=%d, %%sp=%#lx, %%ip=%#lx\n", |
| current->pid, regs->sp, regs->ip); |
| |
| - force_sig_info(SIGSEGV, SEND_SIG_FORCED, current); |
| + force_sig(SIGSEGV, current); |
| } |
| |
| return -1; |
| -- |
| 2.20.1 |
| |