[PATCH #14090] md5_process_block() produces incorrect result with large block sizes

[Andreas Jaeger]

Ping, what should be done with these two patches?

Andreas

On 05/19/2012 08:07 PM, Andreas Jaeger wrote:
>
> sha512.c has theoretically the same problem iff we don't use
> USE_TOTAL128 (which is set for WORDSIZE64):
>
>  From bugzilla:
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> In crypt/sha512.c:123:
>
> #ifdef USE_TOTAL128
>    ctx->total128 += len;
> #else
>    ctx->total[TOTAL128_low] += len;
>    if (ctx->total[TOTAL128_low]<  len)
>      ++ctx->total[TOTAL128_high];
> #endif
>
> But only in remotely hypothetical case of !USE_TOTAL128 and 128-bit size_t and
> then only if someone actually calls sha512_process_block() with this huge
> buffer.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Here's a patch - or should we just ignore it?
>
> Tested on Linux/x86,
>
> Andreas
>
> 	* crypt/sha512.c (sha512_process_block): Likewise.
>
> diff --git a/crypt/sha512.c b/crypt/sha512.c
> index 6e531c5..84fbce1 100644
> --- a/crypt/sha512.c
> +++ b/crypt/sha512.c
> @@ -1,6 +1,6 @@
>   /* Functions to compute SHA512 message digest of files or memory blocks.
>      according to the definition of SHA512 in FIPS 180-2.
> -   Copyright (C) 2007, 2011 Free Software Foundation, Inc.
> +   Copyright (C) 2007-2012 Free Software Foundation, Inc.
>      This file is part of the GNU C Library.
>
>      The GNU C Library is free software; you can redistribute it and/or
> @@ -116,16 +116,18 @@ sha512_process_block (const void *buffer, size_t len, struct sha512_ctx *ctx)
>     uint64_t f = ctx->H[5];
>     uint64_t g = ctx->H[6];
>     uint64_t h = ctx->H[7];
> -
> +#ifndef USE_TOTAL128
> +  uint64_t lolen = len;
> +#endif
>     /* First increment the byte count.  FIPS 180-2 specifies the possible
>        length of the file up to 2^128 bits.  Here we only compute the
>        number of bytes.  Do a double word increment.  */
>   #ifdef USE_TOTAL128
>     ctx->total128 += len;
>   #else
> -  ctx->total[TOTAL128_low] += len;
> -  if (ctx->total[TOTAL128_low]<  len)
> -    ++ctx->total[TOTAL128_high];
> +  ctx->total[TOTAL128_low] += lolen;
> +  ctx->total[TOTAL128_high] += ((uint64_t)len>>  63>>  1)
> +    + (ctx->total [TOTAL128_low]<  lolen);
>   #endif
>
>     /* Process all bytes in the buffer with 128 bytes in each round of
>


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  Andreas Jaeger aj@{suse.com,opensuse.org} Twitter/Identica: jaegerandi
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