* [PATCH] libfs: fix error cast of negative value in simple_attr_write()
@ 2020-09-25 9:15 Yicong Yang
0 siblings, 0 replies; only message in thread
From: Yicong Yang @ 2020-09-25 9:15 UTC (permalink / raw)
To: viro, akinobu.mita, akpm
Cc: linux-fsdevel, linux-kernel, linuxarm, yangyicong
The attr->set() receive a value of u64, but we use simple_strtoll()
for doing the conversion. It will lead to the error cast if user inputs
a negative value.
Use kstrtoull() instead to resolve this issue, -EINVAL will be returned
if a negative value is input.
Fixes: f7b88631a897 ("fs/libfs.c: fix simple_attr_write() on 32bit machines")
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
---
fs/libfs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/libfs.c b/fs/libfs.c
index e0d42e9..803c439 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -975,7 +975,9 @@ 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 */
--
2.8.1
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