From: T.E.Baldwin99@members.leeds.ac.uk (Timothy E Baldwin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: Call syscall_trace_exit even when system call skipped
Date: Sat, 3 Feb 2018 15:21:12 +0000 [thread overview]
Message-ID: <20180203152112.2449-1-T.E.Baldwin99@members.leeds.ac.uk> (raw)
On at least x86 and ARM64, and as documented in the ptrace man page
a skipped system call will still cause a syscall exit ptrace stop.
Previous to this commit 32-bit ARM did not, resulting in strace
being confused when seccomp skips system calls.
This change also impacts programs that use ptrace to skip system calls.
Fixes: ad75b51459ae ("ARM: 7579/1: arch/allow a scno of -1 to not cause a SIGILL")
Signed-off-by: Timothy E Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
---
arch/arm/kernel/entry-common.S | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 99c908226065..88a65157307d 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -288,16 +288,15 @@ __sys_trace:
cmp scno, #-1 @ skip the syscall?
bne 2b
add sp, sp, #S_OFF @ restore stack
- b ret_slow_syscall
-__sys_trace_return:
- str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
+__sys_trace_return_nosave:
+ enable_irq_notrace
mov r0, sp
bl syscall_trace_exit
b ret_slow_syscall
-__sys_trace_return_nosave:
- enable_irq_notrace
+__sys_trace_return:
+ str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
mov r0, sp
bl syscall_trace_exit
b ret_slow_syscall
--
2.14.2
next reply other threads:[~2018-02-03 15:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-03 15:21 Timothy E Baldwin [this message]
2018-03-13 23:58 ` ARM: Call syscall_trace_exit even when system call skipped Dmitry V. Levin
2018-03-15 0:44 ` Kees Cook
2018-03-15 10:38 ` T.E.Baldwin99 at members.leeds.ac.uk
2018-03-15 20:14 ` Kees Cook
2018-09-29 23:03 ` Eugene Syromyatnikov
2018-10-08 7:11 ` Eugene Syromyatnikov
2018-10-08 9:58 ` Vladimir Murzin
2018-10-08 11:00 ` Eugene Syromyatnikov
2018-10-08 18:08 ` Kees Cook
2018-10-08 18:13 ` Russell King - ARM Linux
2018-10-08 18:33 ` Eugene Syromyatnikov
2018-10-08 18:26 ` Eugene Syromyatnikov
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