Messages in this thread Patch in this message | | | From | Yuchen Wei <> | Subject | [PATCH] arm64: audit: fix return value high 32bit truncation problem | Date | Thu, 22 Jul 2021 14:07:07 +0800 |
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From: weiyuchen <weiyuchen3@huawei.com>
Add error code judgment in invoke_syscall() to prevent kernel components such as audit and tracepoint from obtaining incorrect return values. For example:
type=SYSCALL msg=audit(342.780:69): arch=40000028 syscall=235 success=yes exit=4294967235
The syscall return value is -61, but due to the following process in invoke_syscall():
if (is_compat_task()) ret = lower_32_bits(ret); regs->regs[0] = ret;
The return value audit or tracepoint get from regs[0] is 4294967235, which is an incorrect return value.
Signed-off-by: weiyuchen <weiyuchen3@huawei.com> --- arch/arm64/kernel/syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 263d6c1a525f..f9f042d9a088 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -54,7 +54,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, ret = do_ni_syscall(regs, scno); } - if (is_compat_task()) + if (is_compat_task() && !IS_ERR_VALUE(ret)) ret = lower_32_bits(ret); regs->regs[0] = ret; -- 2.12.3
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