linux-kernel - [PATCH 4.14 093/239] signal: Properly deliver SIGSEGV from x86 uprobes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20191119051321.234871754@linuxfoundation.org>
Date:   Tue, 19 Nov 2019 06:18:13 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 093/239] signal: Properly deliver SIGSEGV from x86 uprobes

From: Eric W. Biederman <ebiederm@...ssion.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@...utronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
Signed-off-by: Sasha Levin <sashal@...nel.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 7a87ef1f5b5e6..73391c1bd2a9a 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -987,7 +987,7 @@ arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs
 		pr_err("uprobe: 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