lkml.org 
[lkml]   [2020]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.19 65/91] libfs: fix error cast of negative value in simple_attr_write()
Date
From: Yicong Yang <yangyicong@hisilicon.com>

[ Upstream commit 488dac0c9237647e9b8f788b6a342595bfa40bda ]

The attr->set() receive a value of u64, but simple_strtoll() is used for
doing the conversion. It will lead to the error cast if user inputs a
negative value.

Use kstrtoull() instead of simple_strtoll() to convert a string got from
the user to an unsigned value. The former will return '-EINVAL' if it
gets a negetive value, but the latter can't handle the situation
correctly. Make 'val' unsigned long long as what kstrtoull() takes,
this will eliminate the compile warning on no 64-bit architectures.

Fixes: f7b88631a897 ("fs/libfs.c: fix simple_attr_write() on 32bit machines")
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/1605341356-11872-1-git-send-email-yangyicong@hisilicon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/libfs.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/libfs.c b/fs/libfs.c
index 02158618f4c99..be57e64834e5a 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -868,7 +868,7 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
size_t len, loff_t *ppos)
{
struct simple_attr *attr;
- u64 val;
+ unsigned long long val;
size_t size;
ssize_t ret;

@@ -886,7 +886,9 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
goto out;

attr->set_buf[size] = '\0';
- val = simple_strtoll(attr->set_buf, NULL, 0);
+ ret = kstrtoull(attr->set_buf, 0, &val);
+ if (ret)
+ goto out;
ret = attr->set(attr->data, val);
if (ret == 0)
ret = len; /* on success, claim we got the whole input */
--
2.27.0


\
 
 \ /
  Last update: 2020-11-23 13:39    [W:0.317 / U:0.200 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site