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Date: Tue, 7 Feb 2023 16:45:16 +0200
From: Georgi Guninski <gguninski@...il.com>
To: oss-security@...ts.openwall.com
Subject: SEGV in `alloca(BIG)` and `long pl[BIG]`
Hi v3nd0rz crowd.
Inline are two C warez, which crash on
`alloca(BIG)` and `long pl[BIG]`.
I think alloca(BIG) should return error if BIG>max_signed_size_t.
In C++ `new[BUG]` throws exception and core dumps.
===
#include <stdlib.h>
#include <stdio.h>
#include <alloca.h>
/*
* Author: Georgi Guninski
* CV: https://j.ludost.net/resumegg.pdf
[joro@...ora prim]$ gcc alloca1.c
[joro@...ora prim]$ ./a.out -1
calloc=(nil) alloca()=0x7fff66c931e0
Segmentation fault (core dumped)
[joro@...ora prim]$ ./a.out 4611686018427387904
Bus error (core dumped)
*/
int main(int ac, char **av) {
void *p;
size_t l,cou;
l=atol(av[1]);
p=calloc(l,l);
char *pl=alloca(l);
printf("calloc=%p alloca()=%p\n",p,pl);
if (pl) {
for(cou=0;cou<l;cou++)
pl[cou]=0xcc;
}
return(0);
}
===
#include <stdlib.h>
#include <stdio.h>
/*
* calloc1.c
* * Author: Georgi Guninski
* CV: https://j.ludost.net/resumegg.pdf
[joro@...ora prim]$ gcc calloc1.c
[joro@...ora prim]$ ./a.out -1
calloc=(nil) long[l]=0x7ffe33f7e930
Segmentation fault (core dumped)
* */
int main(int ac, char **av) {
void *p;
size_t l,cou;
l=atol(av[1]);
p=calloc(l,l);
long pl[l];
printf("calloc=%p long[l]=%p\n",p,pl);
if (pl) {
for(cou=0;cou<l;cou++)
pl[cou]=0xcafebabe;
}
return(0);
}
===
===
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