Added strnlen for buffer overflow prevention

1 files changed, 18 insertions, 0 deletions

diff --git a/libs/libc/str.c b/libs/libc/str.c
index 52af5c4..9a30e92 100644
--- a/libs/libc/str.c
+++ b/libs/libc/str.c
@@ -13,6 +13,16 @@ u32 strlen(const char *str)
 	return s - str;
 }
 
+u32 strnlen(const char *str, u32 max)
+{
+	const char *s = str;
+	while (max && *s) {
+		s++;
+		max--;
+	}
+	return s - str;
+}
+
 u32 strlcpy(char *dst, const char *src, u32 size)
 {
 	const char *orig = src;
@@ -231,6 +241,14 @@ u32 strlen_user(const char *str)
 	return ret;
 }
 
+u32 strnlen_user(const char *str, u32 max)
+{
+	stac();
+	u32 ret = strnlen(str, max);
+	clac();
+	return ret;
+}
+
 u32 strlcpy_user(char *dst, const char *src, u32 size)
 {
 	stac();