Hello,
When I fill a large (INT_MAX=0x7FFFFFFF) buffer with random bytes, RAND_bytes()
returns 1 and all seems to be OK, but in the next call to RAND_bytes() I get a
segmentation-fault with OpenSSL 1.0.0c (4GB installed RAM; 3GB free).
A quick look at the core dump shows the following:
In the first call to RAND_bytes() the parameter ''num'' was 0x7FFFFFFF which
leads to ''num_ceil'' (crypto/rand/md_rand.c:361) will be 0x80000002 but this
is negative (-2147483646)...
Then the global variable ''state_index'' in (crypto/rand/md_rand.c:137) is
negative too.
In the second call to RAND_bytes() ''k'' in (crypto/rand/md_rand.c:489) gets
very large (2147482710) and writes into not allocated memory.
Perhaps this is related to #1764: openssl-0.9.8i random generator bug.
More Information:
> user@host:~> cat ssl_rand_test.c
> #include <limits.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <openssl/rand.h>
>
> int main(void)
> {
> {
> unsigned char *buf1 = malloc(INT_MAX);
> printf("RAND_bytes() %d return %d\n", INT_MAX, RAND_bytes(buf1,
> INT_MAX));
> free(buf1);
> }
> {
> unsigned char buf2[9];
> const int num = sizeof(buf2);
> printf("RAND_bytes() %d return %d\n", num, RAND_bytes(buf2, num));
> }
> return EXIT_SUCCESS;
> }
> user@host:~> gcc -g -Wall -pedantic -ansi ssl_rand_test.c -o ssl_rand_test
> -lcrypto
> user@host:~> ./ssl_rand_test
> RAND_bytes() 2147483647 return 1
> Segmentation-fault
>
> user@host:~> lsb_release -a
> LSB Version: n/a
> Distributor ID: SUSE LINUX
> Description: openSUSE 11.4 (x86_64)
> Release: 11.4
> Codename: Celadon
>
> user@host:~> rpm -qi libopenssl-devel
> Name : libopenssl-devel Relocations: (not relocatable)
> Version : 1.0.0c Vendor: openSUSE
> Release : 18.21.1 Build Date: Di 20 Sep 2011
> 13:35:51 CEST
> Install Date: Do 20 Okt 2011 17:33:26 CEST Build Host: build32
> Group : Development/Libraries/C and C++ Source RPM:
> openssl-1.0.0c-18.21.1.src.rpm
> Size : 1382904 License: BSD3c(or similar)
> Signature : RSA/8, Di 20 Sep 2011 13:37:15 CEST, Key ID b88b2fd43dbdc284
> Packager : http://bugs.opensuse.org
> URL : http://www.openssl.org/
> Summary : Include Files and Libraries mandatory for Development
> Description :
> This package contains all necessary include files and libraries needed
> to develop applications that require these.
>
>
>
> Authors:
> --------
> Mark J. Cox <[email protected]>
> Ralf S. Engelschall <[email protected]>
> Dr. Stephen <Henson [email protected]>
> Ben Laurie <[email protected]>
> Bodo Moeller <[email protected]>
> Ulf Moeller <[email protected]>
> Holger Reif <[email protected]>
> Paul C. Sutton <[email protected]>
> Distribution: openSUSE 11.4
>
> user@host:~> gdb ./ssl_rand_test core
> ...
> Program terminated with signal 11, Segmentation fault.
> (gdb) bt
> #0 memcpy () at ../sysdeps/x86_64/memcpy.S:102
> #1 0x00007fbcc309f83f in SHA1_Update (c=0x602010, data_=0x7fbc433dcf0b,
> len=<value optimized out>) at /usr/include/bits/string3.h:52
> #2 0x00007fbcc31009ff in ssleay_rand_bytes (buf=0x7fff81516360 "", num=0) at
> md_rand.c:492
> #3 0x0000000000400798 in main () at ssl_rand_test.c:16
> (gdb) print k
> $1 = <value optimized out>
> (gdb) print (st_idx+10)-st_num
> $2 = 2147482710
> (gdb) print st_idx
> $3 = -2147483573
> (gdb) print state_index
> $4 = -2147483563
> (gdb) print st_num
> $5 = 1023
> (gdb) print state_num
> $6 = 1023
Would it be better when num_ceil, st_idx, st_num, state_index and state_num are
unsigned integers?
Best regards
Yves Jäger
atosworldline.com
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#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <openssl/rand.h>
int main(void)
{
{
unsigned char *buf1 = malloc(INT_MAX);
printf("RAND_bytes() %d return %d\n", INT_MAX, RAND_bytes(buf1, INT_MAX));
free(buf1);
}
{
unsigned char buf2[9];
const int num = sizeof(buf2);
printf("RAND_bytes() %d return %d\n", num, RAND_bytes(buf2, num));
}
return EXIT_SUCCESS;
}
