strncmp(str, const, len) is error-prone because len
is easy to have typo.
The example is the hard-coded len has counting error
or sizeof(const) forgets - 1.
So we prefer using newly introduced str_has_prefix()
to substitute such strncmp to make code better.
Signed-off-by: Chuhong Yuan <hsleste...@gmail.com>
---
Changes in v4:
- Eliminate assignments in if conditions.
kernel/user_namespace.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 8eadadc478f9..bd5702f9273a 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1138,6 +1138,7 @@ ssize_t proc_setgroups_write(struct file *file, const
char __user *buf,
char kbuf[8], *pos;
bool setgroups_allowed;
ssize_t ret;
+ size_t len;
/* Only allow a very narrow range of strings to be written */
ret = -EINVAL;
@@ -1153,16 +1154,19 @@ ssize_t proc_setgroups_write(struct file *file, const
char __user *buf,
/* What is being requested? */
ret = -EINVAL;
- if (strncmp(pos, "allow", 5) == 0) {
- pos += 5;
+
+ len = str_has_prefix(pos, "allow");
+ if (len) {
+ pos += len;
setgroups_allowed = true;
+ } else {
+ len = str_has_prefix(pos, "deny");
+ if (len) {
+ pos += len;
+ setgroups_allowed = false;
+ } else
+ goto out;
}
- else if (strncmp(pos, "deny", 4) == 0) {
- pos += 4;
- setgroups_allowed = false;
- }
- else
- goto out;
/* Verify there is not trailing junk on the line */
pos = skip_spaces(pos);
--
2.20.1
