| From 3b64c2a6eece36b5039e2f6a7cd7ae929f27df24 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sat, 21 Nov 2020 22:17:19 -0800 |
| Subject: libfs: fix error cast of negative value in simple_attr_write() |
| |
| 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 |
| |