From 9795c61464413f876d2248271d1c074fe63df66d Mon Sep 17 00:00:00 2001 From: Ben Wiederhake Date: Sun, 23 Aug 2020 12:34:08 +0200 Subject: [PATCH] LibC: Prevent slowness and overrun in strdup/strndup strdup: Because the length is already known at the time of copying, there is no need to use strcpy (which has to check every single byte, and thus tends to be slower than memcpy). strndup: If 'str' is not NUL-terminated, strndup used to run off into the adjacent memory region. This can be fixed by using the proper strlen variant: strnlen. --- Libraries/LibC/string.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Libraries/LibC/string.cpp b/Libraries/LibC/string.cpp index cadd9669d6..4d25cd8fd2 100644 --- a/Libraries/LibC/string.cpp +++ b/Libraries/LibC/string.cpp @@ -94,13 +94,14 @@ char* strdup(const char* str) { size_t len = strlen(str); char* new_str = (char*)malloc(len + 1); - strcpy(new_str, str); + memcpy(new_str, str, len); + new_str[len] = '\0'; return new_str; } char* strndup(const char* str, size_t maxlen) { - size_t len = min(strlen(str), maxlen); + size_t len = strnlen(str, maxlen); char* new_str = (char*)malloc(len + 1); memcpy(new_str, str, len); new_str[len] = 0;