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[Bug libc/6409] New: (glibc 2.7) -D_FORTIFY_SOURCE discards qualifier overrides on {str,mem}cpy
- From: "kees at outflux dot net" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: 15 Apr 2008 16:53:24 -0000
- Subject: [Bug libc/6409] New: (glibc 2.7) -D_FORTIFY_SOURCE discards qualifier overrides on {str,mem}cpy
- Reply-to: sourceware-bugzilla at sourceware dot org
The following source, without the "(void*)" overrides, will throw an warning
(as expected), when compiled with -Wall:
$ gcc -o memcpy-fortify -Wall memcpy-fortify.c
memcpy-fortify.c: In function 'main':
memcpy-fortify.c:21: warning: passing argument 1 of 'memcpy' discards
qualifiers from pointer target type
memcpy-fortify.c:22: warning: passing argument 1 of 'strcpy' discards
qualifiers from pointer target type
With "(void*)" it is (as expected) silent. With -O2, it is silent, but with
-D_FORTIFY_SOURCE != 0, the qualifier override is ignored:
$ gcc -o memcpy-fortify -Wall -O2 -D_FORTIFY_SOURCE=2 memcpy-fortify.c
memcpy-fortify.c: In function 'main':
memcpy-fortify.c:21: warning: passing argument 1 of 'memcpy' discards
qualifiers from pointer target type
memcpy-fortify.c:22: warning: passing argument 1 of 'strcpy' discards
qualifiers from pointer target type
This will cause problems for builds that run with -Werror.
/*
* gcc -o memcpy-fortify -Wall -Werror -O2 -D_FORTIFY_SOURCE=2 memcpy-fortify.c
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <stdint.h>
#include <inttypes.h>
int main(int argc, char * argv[])
{
char *foo = strdup("string one");
char *bar = strdup("string two");
const char *baz = (const char *)foo;
printf("%s\n", foo);
memcpy((void*)baz, bar, strlen(bar)+1);
strcpy((void*)baz, bar);
printf("%s\n", foo);
return 0;
}
--
Summary: (glibc 2.7) -D_FORTIFY_SOURCE discards qualifier
overrides on {str,mem}cpy
Product: glibc
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: drepper at redhat dot com
ReportedBy: kees at outflux dot net
CC: glibc-bugs at sources dot redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=6409
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