[erlang-patches] [PATCH] crypto: fix a few memleaks/undefined pointer dereferences

Sverker Eriksson <>
Fri Dec 20 16:13:42 CET 2013


On 12/16/2013 05:24 PM, Florian Zumbiehl wrote:
>>> what I am wondering about is
>>> whether it is correct that almost none of the OpenSSL calls in crypto are
>>> being checked for memory allocation failures!?
>> Not sure what you mean. Can you give an example.
> For example, almost none of the bignum calls (BN_.*) are checked for error
> returns, the OpensSSL documentation explicitly states that you always have
> to check returns because it uses dynamic memory allocation and thus
> allocation failures might occur. Looking around in the code, I also found a
> call to HMAC_Init(), for example, which I'm pretty sure also uses dynamic
> allocation (and in any case, the OpenSSL documentation shows that is has an
> error return, even though the possible causes of failure are not listed),
> and then there are all those <algorithm>_Init calls and the like, of which
> I don't have a clue whether they do use dynamic allocation, but in any
> case, the OpenSSL documentation shows they also have error returns, and
> those generally don't seem to be checked either.
>
A simple fix to this would be to let the crypto_alloc (in 
crypto_callback.c) to call abort() if the allocation failed as that is 
the strategy otherwise in out-of-memory scenarios. Thus a "nice crash" 
with an "Out of memory" message instead of a segmentation violation.

/Sverker



More information about the erlang-patches mailing list