| http://bugs.gentoo.org/213833 |
| |
| commit 913c09becd9df89dbd9b9f386e7f35c240d5efe8 |
| Author: Bruno Haible <bruno@clisp.org> |
| Date: Fri Oct 19 01:50:42 2007 +0200 |
| |
| Don't use %n on glibc >= 2.3 systems. |
| |
| diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c |
| index f563823..5d818aa 100644 |
| --- a/lib/vasnprintf.c |
| +++ b/lib/vasnprintf.c |
| @@ -3385,9 +3385,21 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp, |
| #endif |
| *p = dp->conversion; |
| #if USE_SNPRINTF |
| +# if !(__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)) |
| p[1] = '%'; |
| p[2] = 'n'; |
| p[3] = '\0'; |
| +# else |
| + /* On glibc2 systems from glibc >= 2.3 - probably also older |
| + ones - we know that snprintf's returns value conforms to |
| + ISO C 99: the gl_SNPRINTF_DIRECTIVE_N test passes. |
| + Therefore we can avoid using %n in this situation. |
| + On glibc2 systems from 2004-10-18 or newer, the use of %n |
| + in format strings in writable memory may crash the program |
| + (if compiled with _FORTIFY_SOURCE=2), so we should avoid it |
| + in this situation. */ |
| + p[1] = '\0'; |
| +# endif |
| #else |
| p[1] = '\0'; |
| #endif |
