NAME
ssp – bounds checked libc functions
LIBRARY
library “libssp”
SYNOPSIS
#include <ssp/stdio.h>
int
sprintf(char *str, const char *fmt, ...);
int
vsprintf(char *str, const char *fmt, va_list ap);
int
snprintf(char *str, size_t len, const char *fmt, ...);
int
vsnprintf(char *str, size_t len, const char *fmt, va_list ap);
char *
fgets(char *str, int len, FILE *fp);
#include <ssp/string.h>
void *
memcpy(void *str, const void *ptr, size_t len);
void *
memmove(void *str, const void *ptr, size_t len);
void *
memset(void *str, int val, size_t len);
char *
stpcpy(char *str, const char *ptr);
char *
strcpy(char *str, const char *ptr);
char *
strcat(char *str, const char *ptr);
char *
strncpy(char *str, const char *ptr, size_t len);
char *
strncat(char *str, const char *ptr, size_t len);
#include <ssp/strings.h>
void *
bcopy(const void *ptr, void *str, size_t len);
void *
bzero(void *str, size_t len);
#include <ssp/unistd.h>
ssize_t
read(int fd, void *str, size_t len);
int
readlink(const char * restrict path, char * restrict str, size_t len);
int
getcwd(char *str, size_t len);
DESCRIPTION
When _FORTIFY_SOURCE bounds checking is enabled as described below, the above functions get overwritten to use the __builtin_object_size(3) function to compute the size of str, if known at compile time, and perform bounds check on it in order to avoid data buffer or stack buffer overflows. If an overflow is detected, the routines will call abort(3).
To enable these function overrides the following should be added to the clang(1) or gcc(1) command line: “-D_FORTIFY_SOURCE=1” or “-D_FORTIFY_SOURCE=2”.
If _FORTIFY_SOURCE is set to 1 the code will compute the maximum possible buffer size for str, and if set to 2 it will compute the minimum buffer size.
SEE ALSO
clang(1), gcc(1), __builtin_object_size(3), stdio(3), string(3), security(7)
HISTORY
The ssp library appeared in NetBSD 4.0. This version of the ssp library replaced the GNU library of the same name in FreeBSD 12.2.