linux-kernel - [PATCH 3/4] arch/arm: allow a scno of -1 to not cause a SIGILL

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: <1351799199-6853-4-git-send-email-keescook@chromium.org>
Date:	Thu,  1 Nov 2012 12:46:38 -0700
From:	Kees Cook <keescook@...omium.org>
To:	linux-kernel@...r.kernel.org
Cc:	Russell King <linux@....linux.org.uk>,
	Will Deacon <will.deacon@....com>,
	Will Drewry <wad@...omium.org>,
	Geremy Condra <gcondra@...gle.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Catalin Marinas <catalin.marinas@....com>,
	Kees Cook <keescook@...omium.org>
Subject: [PATCH 3/4] arch/arm: allow a scno of -1 to not cause a SIGILL

From: Will Drewry <wad@...omium.org>

On tracehook-friendly platforms, a system call number of -1 falls
through without running much code or taking much action.

ARM is different.  This adds a lightweight check to arm_syscall()
to make sure that ARM behaves the same way.

Signed-off-by: Will Drewry <wad@...omium.org>
Signed-off-by: Kees Cook <keescook@...omium.org>
---
 arch/arm/kernel/traps.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index b0179b8..f303ea6 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -540,6 +540,10 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 	struct thread_info *thread = current_thread_info();
 	siginfo_t info;
 
+	/* Emulate/fallthrough. */
+	if (no == -1)
+		return regs->ARM_r0;
+
 	if ((no >> 16) != (__ARM_NR_BASE>> 16))
 		return bad_syscall(no, regs);
 
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/