diff options
Diffstat (limited to 'libio/iovsprintf.c')
-rw-r--r-- | libio/iovsprintf.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/libio/iovsprintf.c b/libio/iovsprintf.c index d3f23be..9050038 100644 --- a/libio/iovsprintf.c +++ b/libio/iovsprintf.c @@ -77,8 +77,18 @@ __vsprintf_internal (char *string, size_t maxlen, sf._sbf._f._lock = NULL; #endif _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL); - _IO_JUMPS (&sf._sbf) = &_IO_str_chk_jumps; - string[0] = '\0'; + /* When called from fortified sprintf/vsprintf, erase the destination + buffer and try to detect overflows. When called from regular + sprintf/vsprintf, do not erase the destination buffer, because + known user code relies on this behavior (even though its undefined + by ISO C), nor try to detect overflows. */ + if ((mode_flags & PRINTF_CHK) != 0) + { + _IO_JUMPS (&sf._sbf) = &_IO_str_chk_jumps; + string[0] = '\0'; + } + else + _IO_JUMPS (&sf._sbf) = &_IO_str_jumps; _IO_str_init_static_internal (&sf, string, (maxlen == -1) ? -1 : maxlen - 1, string); |