[openssl-dev] [openssl.org #4218] Invalid typecasting in CRYPTO_ctr128_encrypt

[Kurt Roeckx via RT]

On Tue, Jan 05, 2016 at 05:36:35PM +0000, Bjorn Kornefalk via RT wrote:
> OpenSSL 1.0.2e
> 
> At line 156 of crypto/modes/ctr128.c
> 
> const unsigned char *in, 
> unsigned char *out,
> unsigned char ivec[16],
> unsigned char ecount_buf[16]
> 
>    *(size_t *)(out + n) =
>        *(size_t *)(in + n) ^ *(size_t *)(ecount_buf + n);
> 
> If the buffers are not aligned, the application crashes due to the invalid 
> type casting of unsigned char (1 byte) to size_t (4 to 8 bytes for most 
> CPU:s).

You should not run into that issue if STRICT_ALIGNMENT is defined.

Currently this is set by:
#define STRICT_ALIGNMENT 1
#ifndef PEDANTIC
# if defined(__i386)    || defined(__i386__)    || \
     defined(__x86_64)  || defined(__x86_64__)  || \
     defined(_M_IX86)   || defined(_M_AMD64)    || defined(_M_X64) || \
     defined(__aarch64__)                       || \
     defined(__s390__)  || defined(__s390x__)
#  undef STRICT_ALIGNMENT
# endif
#endif


Kurt