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tracing: Don't use the address of the buffer array name in copy_from_user

PATCH In review Wang Xiaoqiang 2 participants 2 messages Apr 18, 2016 – Apr 26, 2016 Tracing

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Wang Xiaoqiang

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#0 lore raw

PATCH 1/1 tracing: Don't use the address of the buffer array name in copy_from_user

Hi, all,

Quoted 1 line

From 7dbacb179a4d5f9ac9d7e1b3733664b3b0fe23ae Mon Sep 17 00:00:00 2001

From: Wang Xiaoqiang <[email protected]>
Date: Mon, 18 Apr 2016 14:58:15 +0800
Subject: [PATCH] tracing: Don't use the address of the buffer array name in
copy_from_user

Fix the problem as follows:

    ...
    char buf[64];
    ...
    if (copy_from_user(&buf, ubuf, cnt))
    ...

Even though the value of "&buf" equals "buf", but there is no need to get the address of the "buf" again. Use "buf" replace "&buf".

Signed-off-by Wang Xiaoqiang <[email protected]>
---
 kernel/trace/trace.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
kernel/trace/trace.c +3 -3
index a2f0b9f..422ab57 100644
@@ -3658,7 +3658,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 	if (cnt >= sizeof(buf))
 		return -EINVAL;
 
-	if (copy_from_user(&buf, ubuf, cnt))
+	if (copy_from_user(buf, ubuf, cnt))
 		return -EFAULT;
 
 	buf[cnt] = 0;

@@ -4474,7 +4474,7 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 	if (cnt > MAX_TRACER_SIZE)
 		cnt = MAX_TRACER_SIZE;
 
-	if (copy_from_user(&buf, ubuf, cnt))
+	if (copy_from_user(buf, ubuf, cnt))
 		return -EFAULT;
 
 	buf[cnt] = 0;

@@ -5264,7 +5264,7 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
 	if (cnt >= sizeof(buf))
 		return -EINVAL;
 
-	if (copy_from_user(&buf, ubuf, cnt))
+	if (copy_from_user(buf, ubuf, cnt))
 		return -EFAULT;
 
 	buf[cnt] = 0;
Signature · 1 line
2.1.4
maintainer
#1 lore raw
Quoted 9 lines · On Mon, 18 Apr 2016 15:23:29 +0800 Wang Xiaoqiang <[email protected]> wrote:

Hi, all,

From 7dbacb179a4d5f9ac9d7e1b3733664b3b0fe23ae Mon Sep 17 00:00:00 2001
From: Wang Xiaoqiang <[email protected]>
Date: Mon, 18 Apr 2016 14:58:15 +0800
Subject: [PATCH] tracing: Don't use the address of the buffer array name in
copy_from_user

Fix the problem as follows:

What problem is being fixed?

Quoted 9 lines
    ...
    char buf[64];
    ...
    if (copy_from_user(&buf, ubuf, cnt))
    ...

Even though the value of "&buf" equals "buf", but there is no need to get the address of the "buf" again. Use "buf" replace "&buf".

I'll take this, but more as a cleanup and not a "fix".

Thanks,

-- Steve

Quoted 37 lines
Signed-off-by Wang Xiaoqiang <[email protected]>
---
 kernel/trace/trace.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
kernel/trace/trace.c +3 -3
index a2f0b9f..422ab57 100644
@@ -3658,7 +3658,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 	if (cnt >= sizeof(buf))
 		return -EINVAL;
 
-	if (copy_from_user(&buf, ubuf, cnt))
+	if (copy_from_user(buf, ubuf, cnt))
 		return -EFAULT;
 
 	buf[cnt] = 0;

@@ -4474,7 +4474,7 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 	if (cnt > MAX_TRACER_SIZE)
 		cnt = MAX_TRACER_SIZE;
 
-	if (copy_from_user(&buf, ubuf, cnt))
+	if (copy_from_user(buf, ubuf, cnt))
 		return -EFAULT;
 
 	buf[cnt] = 0;

@@ -5264,7 +5264,7 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
 	if (cnt >= sizeof(buf))
 		return -EINVAL;
 
-	if (copy_from_user(&buf, ubuf, cnt))
+	if (copy_from_user(buf, ubuf, cnt))
 		return -EFAULT;
 
 	buf[cnt] = 0;