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From: Yuchen Wei <weiyuchen3@huawei.com>
To: <catalin.marinas@arm.com>, <will@kernel.org>
Cc: <mark.rutland@arm.com>, <vincenzo.frascino@arm.com>,
	<keescook@chromium.org>, <pcc@google.com>,
	<weiyuchen3@huawei.com>, <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH] arm64: audit: fix return value high 32bit truncation problem
Date: Thu, 22 Jul 2021 14:07:07 +0800	[thread overview]
Message-ID: <20210722060707.531-1-weiyuchen3@huawei.com> (raw)

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


WARNING: multiple messages have this Message-ID (diff)
From: Yuchen Wei <weiyuchen3@huawei.com>
To: <catalin.marinas@arm.com>, <will@kernel.org>
Cc: <mark.rutland@arm.com>, <vincenzo.frascino@arm.com>,
	<keescook@chromium.org>, <pcc@google.com>,
	<weiyuchen3@huawei.com>, <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH] arm64: audit: fix return value high 32bit truncation problem
Date: Thu, 22 Jul 2021 14:07:07 +0800	[thread overview]
Message-ID: <20210722060707.531-1-weiyuchen3@huawei.com> (raw)

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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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2021-07-22  6:07 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-22  6:07 Yuchen Wei [this message]
2021-07-22  6:07 ` [PATCH] arm64: audit: fix return value high 32bit truncation problem Yuchen Wei
2021-07-30 12:22 ` Will Deacon
2021-07-30 12:22   ` Will Deacon
2021-07-30 14:23   ` Mark Rutland
2021-07-30 14:23     ` Mark Rutland

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