possible user error / memory leak using RSA_new() and RSA

Stuart Weatherby

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Apr 19, 2010, 5:07:10 PM4/19/10

to

Hi List,

I am trying to figure out why there is a memory leak using RSA_new & RSA_free:
Below is a code sample (which will produce a memory leak) and the relevent valgrind output. I have checked the documentation but I still fail to see my error.

As I understand the docuumentation, RSA_free() is the only required call to free memory allocated using the RSA_new() function.

Thanks,

Stuart

int main (void)
{
   FILE *fp;
   RSA *p = NULL;
   char *pt = "hi\0";
   char pt_0 = *pt;
   int pt_len = strlen(pt);
   unsigned char *ct;
   int ct_len = 0;

   if ((p = RSA_new()) == NULL)
      return 1;
   if ((fp = fopen ("pub.key", "rb")) == NULL)
      return 2;
   if ((p = PEM_read_RSA_PUBKEY(fp, NULL, NULL, NULL)) == NULL)
   {
      fclose(fp);
      return 3;
   }
   fclose(fp);
   ct = malloc(RSA_size(p));
   if(RSA_public_encrypt(pt_len,(unsigned char *) pt,ct, p, RSA_PKCS1_OAEP_PADDING) == -1)
     return 4;
   free(ct);
   RSA_free(p);
   return 0;
}

Here is the valgrind output:

==2330== 528 bytes in 10 blocks are still reachable in loss record 2 of 2
==2330==    at 0x4A05809: malloc (vg_replace_malloc.c:149)
==2330==    by 0x35156DAD51: CRYPTO_malloc (in /lib64/libcrypto.so.0.9.8e)
==2330==    by 0x351567EAC8: lh_new (in /lib64/libcrypto.so.0.9.8e)
==2330==    by 0x351565B4C4: (within /lib64/libcrypto.so.0.9.8e)
==2330==    by 0x351565B5E5: (within /lib64/libcrypto.so.0.9.8e)
==2330==    by 0x351565B98A: (within /lib64/libcrypto.so.0.9.8e)
==2330==    by 0x351566F9B3: RSA_new_method (in /lib64/libcrypto.so.0.9.8e)
==2330==    by 0x40083D: main (rsatest.c:24)
==2330==
==2330== LEAK SUMMARY:
==2330==    definitely lost: 168 bytes in 1 blocks.
==2330==      possibly lost: 0 bytes in 0 blocks.
==2330==    still reachable: 528 bytes in 10 blocks.
==2330==         suppressed: 0 bytes in 0 blocks.

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Dr. Stephen Henson

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Apr 19, 2010, 6:12:53 PM4/19/10

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You are allocating an RSA structure then completely overwriting the pointer
with a new one. Leaving the original as the leak.

Delete the RSA_new() call.

Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org

Mounir IDRASSI

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Apr 19, 2010, 6:29:48 PM4/19/10

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Hi,

Remove the unecessary call to RSA_new and the memory leak will
disappear!! (The variable p est allocated by PEM_read_RSA_PUBKEY)

Cheers,
--
Mounir IDRASSI
IDRIX
http://www.idrix.fr

On 4/19/2010 11:07 PM, Stuart Weatherby wrote:
> Hi List,
>

> I am trying to figure out why there is a memory leak using RSA_new& RSA_free:

> Here is the valgrind output:
>
> ==2330== 528 bytes in 10 blocks are still reachable in loss record 2 of 2
> ==2330== at 0x4A05809: malloc (vg_replace_malloc.c:149)
> ==2330== by 0x35156DAD51: CRYPTO_malloc (in /lib64/libcrypto.so.0.9.8e)
> ==2330== by 0x351567EAC8: lh_new (in /lib64/libcrypto.so.0.9.8e)
> ==2330== by 0x351565B4C4: (within /lib64/libcrypto.so.0.9.8e)
> ==2330== by 0x351565B5E5: (within /lib64/libcrypto.so.0.9.8e)
> ==2330== by 0x351565B98A: (within /lib64/libcrypto.so.0.9.8e)
> ==2330== by 0x351566F9B3: RSA_new_method (in /lib64/libcrypto.so.0.9.8e)
> ==2330== by 0x40083D: main (rsatest.c:24)
> ==2330==
> ==2330== LEAK SUMMARY:
> ==2330== definitely lost: 168 bytes in 1 blocks.
> ==2330== possibly lost: 0 bytes in 0 blocks.
> ==2330== still reachable: 528 bytes in 10 blocks.
> ==2330== suppressed: 0 bytes in 0 blocks.
>
>

Stuart Weatherby

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Apr 19, 2010, 7:02:16 PM4/19/10

to

Thanks Steve,

After commenting out lines 24 & 25 there is still unfree'd memory:

Stuart

==8155== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 4 from 1)
==8155== malloc/free: in use at exit: 528 bytes in 10 blocks.
==8155== malloc/free: 137 allocs, 127 frees, 13,340 bytes allocated.
==8155== For counts of detected errors, rerun with: -v
==8155== searching for pointers to 10 not-freed blocks.
==8155== checked 227,584 bytes.
==8155==
==8155== 528 bytes in 10 blocks are still reachable in loss record 1 of 1
==8155==    at 0x4A05809: malloc (vg_replace_malloc.c:149)
==8155==    by 0x35156DAD51: CRYPTO_malloc (in /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x351567EAC8: lh_new (in /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x351565B4C4: (within /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x351565B5E5: (within /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x351565B98A: (within /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x351567698F: BIO_set (in /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x3515676A19: BIO_new (in /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x351569DE71: PEM_ASN1_read (in /lib64/libcrypto.so.0.9.8e)
==8155==    by 0x400836: main (rsatest.c:30)
==8155==
==8155== LEAK SUMMARY:
==8155==    definitely lost: 0 bytes in 0 blocks.
==8155==      possibly lost: 0 bytes in 0 blocks.
==8155==    still reachable: 528 bytes in 10 blocks.
==8155==         suppressed: 0 bytes in 0 blocks.

----- Original Message ----
From: Dr. Stephen Henson <st...@openssl.org>
To: openss...@openssl.org
Sent: Mon, April 19, 2010 3:12:53 PM
Subject: Re: possible user error / memory leak using RSA_new() and RSA_free();

On Mon, Apr 19, 2010, Stuart Weatherby wrote:

> Hi List,
>
> I am trying to figure out why there is a memory leak using RSA_new & RSA_free:

You are allocating an RSA structure then completely overwriting the pointer

with a new one. Leaving the original as the leak.

Delete the RSA_new() call.

Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org

Dr. Stephen Henson

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Apr 19, 2010, 7:38:14 PM4/19/10

to

On Mon, Apr 19, 2010, Stuart Weatherby wrote:

> Thanks Steve,
>
> After commenting out lines 24 & 25 there is still unfree'd memory:
>

http://www.openssl.org/support/faq.html#PROG13

Stuart Weatherby

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Apr 20, 2010, 2:03:50 AM4/20/10

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Steve & Mounir,

Thanks a lot for answering my questions.

Stuart

----- Original Message ----
From: Dr. Stephen Henson <st...@openssl.org>
To: openss...@openssl.org
Sent: Mon, April 19, 2010 4:38:14 PM
Subject: Re: possible user error / memory leak using RSA_new() and RSA_free();

http://www.openssl.org/support/faq.html#PROG13

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