Commit 55c84a5c authored by Kees Cook's avatar Kees Cook
Browse files

fortify: strcat: Move definition to use fortified strlcat() 



Move the definition of fortified strcat() to after strlcat() to use it
for bounds checking.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 605395cd

include/linux/fortify-string.h

+26 −27
Original line number Diff line number Diff line
@@ -151,33 +151,6 @@ char *strncpy(char * const POS p, const char *q, __kernel_size_t size) 
	return __underlying_strncpy(p, q, size);

}



/**

 * strcat - Append a string to an existing string

 *

 * @p: pointer to NUL-terminated string to append to

 * @q: pointer to NUL-terminated source string to append from

 *

 * Do not use this function. While FORTIFY_SOURCE tries to avoid

 * read and write overflows, this is only possible when the

 * destination buffer size is known to the compiler. Prefer

 * building the string with formatting, via scnprintf() or similar.

 * At the very least, use strncat().

 *

 * Returns @p.

 *

 */

__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)

char *strcat(char * const POS p, const char *q)

{

	const size_t p_size = __member_size(p);



	if (p_size == SIZE_MAX)

		return __underlying_strcat(p, q);

	if (strlcat(p, q, p_size) >= p_size)

		fortify_panic(__func__);

	return p;

}



extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);

/**

 * strnlen - Return bounded count of characters in a NUL-terminated string
@@ -435,6 +408,32 @@ size_t strlcat(char * const POS p, const char * const POS q, size_t avail) 
	return wanted;

}



/* Defined after fortified strlcat() to reuse it. */

/**

 * strcat - Append a string to an existing string

 *

 * @p: pointer to NUL-terminated string to append to

 * @q: pointer to NUL-terminated source string to append from

 *

 * Do not use this function. While FORTIFY_SOURCE tries to avoid

 * read and write overflows, this is only possible when the

 * destination buffer size is known to the compiler. Prefer

 * building the string with formatting, via scnprintf() or similar.

 * At the very least, use strncat().

 *

 * Returns @p.

 *

 */

__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)

char *strcat(char * const POS p, const char *q)

{

	const size_t p_size = __member_size(p);



	if (strlcat(p, q, p_size) >= p_size)

		fortify_panic(__func__);

	return p;

}



/**

 * strncat - Append a string to an existing string

 *