From 4e2f43f842ef5e253cc23383645adbaa03cedb86 Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Wed, 7 Mar 2018 14:32:03 -0500 Subject: Use PRINTF_FORTIFY instead of _IO_FLAGS2_FORTIFY (bug 11319) The _chk variants of all of the printf functions become much simpler. This is the last thing that we needed _IO_acquire_lock_clear_flags2 for, so it can go as well. I took the opportunity to make the headers included and the names of all local variables consistent across all the affected files. Since we ultimately want to get rid of __no_long_double as well, it must be possible to get all of the nontrivial effects of the _chk functions by calling the _internal functions with appropriate flags. For most of the __(v)xprintf_chk functions, this is covered by PRINTF_FORTIFY plus some up-front argument checks that can be duplicated. However, __(v)sprintf_chk installs a custom jump table so that it can crash instead of overflowing the output buffer. This functionality is moved to __vsprintf_internal, which now has a 'maxlen' argument like __vsnprintf_internal; to get the unsafe behavior of ordinary (v)sprintf, pass -1 for that argument. obstack_printf_chk and obstack_vprintf_chk are no longer in the same file. As a side-effect of the unification of both fortified and non-fortified vdprintf initialization, this patch fixes bug 11319 for __dprintf_chk and __vdprintf_chk, which was previously fixed only for dprintf and vdprintf by the commit commit 7ca890b88e6ab7624afb1742a9fffb37ad5b3fc3 Author: Ulrich Drepper Date: Wed Feb 24 16:07:57 2010 -0800 Fix reporting of I/O errors in *dprintf functions. This patch adds a test case to avoid regressions. Tested for powerpc and powerpc64le. --- debug/snprintf_chk.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) (limited to 'debug/snprintf_chk.c') diff --git a/debug/snprintf_chk.c b/debug/snprintf_chk.c index cddba37109..984b5e8932 100644 --- a/debug/snprintf_chk.c +++ b/debug/snprintf_chk.c @@ -15,25 +15,29 @@ License along with the GNU C Library; if not, see . */ -#include #include -#include +#include /* Write formatted output into S, according to the format string FORMAT, writing no more than MAXLEN characters. */ -/* VARARGS5 */ int -___snprintf_chk (char *s, size_t maxlen, int flags, size_t slen, +___snprintf_chk (char *s, size_t maxlen, int flag, size_t slen, const char *format, ...) { - va_list arg; - int done; + if (__glibc_unlikely (slen < maxlen)) + __chk_fail (); - va_start (arg, format); - done = __vsnprintf_chk (s, maxlen, flags, slen, format, arg); - va_end (arg); + /* For flag > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n + can only come from read-only format strings. */ + unsigned int mode = (flag > 0) ? PRINTF_FORTIFY : 0; + va_list ap; + int ret; - return done; + va_start (ap, format); + ret = __vsnprintf_internal (s, maxlen, format, ap, mode); + va_end (ap); + + return ret; } ldbl_strong_alias (___snprintf_chk, __snprintf_chk) -- cgit v1.2.3