From 2b4be69eee372e1010af2302e82c3d0cf1d875e9 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Sun, 18 May 2014 21:05:39 +0100 Subject: [PATCH] [libc] Prevent strndup() from reading beyond the end of the string strndup() may be called on a string which is not NUL-terminated. Use strnlen() instead of strlen() to ensure that we do not read beyond the end of such a string. Add self-tests for strndup(), including a test case with an unterminated string. Originally-fixed-by: Marin Hannache Signed-off-by: Michael Brown --- src/core/string.c | 4 +--- src/tests/string_test.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/src/core/string.c b/src/core/string.c index 190007a4..e53c283c 100644 --- a/src/core/string.c +++ b/src/core/string.c @@ -337,11 +337,9 @@ void * memchr(const void *s, int c, size_t n) char * strndup(const char *s, size_t n) { - size_t len = strlen(s); + size_t len = strnlen(s,n); char *new; - if (len>n) - len = n; new = malloc(len+1); if (new) { new[len] = '\0'; diff --git a/src/tests/string_test.c b/src/tests/string_test.c index 934c537c..3b48d9f3 100644 --- a/src/tests/string_test.c +++ b/src/tests/string_test.c @@ -134,6 +134,26 @@ static void string_test_exec ( void ) { ok ( strcmp ( dup, orig ) == 0 ); free ( dup ); } + + /* Test strndup() */ + { + const char *normal = "testing testing"; + const char unterminated[6] = { 'h', 'e', 'l', 'l', 'o', '!' }; + char *dup; + dup = strndup ( normal, 32 ); + ok ( dup != NULL ); + ok ( dup != normal ); + ok ( strcmp ( dup, normal ) == 0 ); + free ( dup ); + dup = strndup ( normal, 4 ); + ok ( dup != NULL ); + ok ( strcmp ( dup, "test" ) == 0 ); + free ( dup ); + dup = strndup ( unterminated, 5 ); + ok ( dup != NULL ); + ok ( strcmp ( dup, "hello" ) == 0 ); + free ( dup ); + } } /** String self-test */