NAME
ssp —
bounds checked libc
functions
LIBRARY
Buffer Overflow Protection Library (libssp, -lssp)
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.