strict_strto* is not strict enough

It decodes "\n" as 0, which is bad, because stray echo into backlight
will turn your backlight off, etc...

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: Yi Yang <yi.y.yang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 98d632277ca8..0fbd0121d91d 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -170,6 +170,8 @@ int strict_strtoul(const char *cp, unsigned int base, unsigned long *res)
                 return -EINVAL;
 
         val = simple_strtoul(cp, &tail, base);
+        if (tail == cp)
+                return -EINVAL;
         if ((*tail == '\0') ||
                 ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
                 *res = val;
@@ -241,6 +243,8 @@ int strict_strtoull(const char *cp, unsigned int base, unsigned long long *res)
                 return -EINVAL;
 
         val = simple_strtoull(cp, &tail, base);
+        if (tail == cp)
+                return -EINVAL;
         if ((*tail == '\0') ||
                 ((len == (size_t)(tail - cp) + 1) && (*tail == '\n'))) {
                 *res = val;