Subject: Re: [PATCH 1/2] Limit the size of the data block passed to SHA1_Update()

From: Torsten Bögershausen <[email-masked]>
Date: Tue, 03 Nov 2015 12:51:24 +0100

On 11/03/2015 07:58 AM, [email-masked] wrote:
> From: Atousa Pahlevan Duprat <[email-masked]>
Minor comments inline
> diff --git a/block-sha1/sha1.h b/block-sha1/sha1.h
> index b864df6..d085412 100644
> --- a/block-sha1/sha1.h
> +++ b/block-sha1/sha1.h
> @@ -18,5 +18,5 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx);
>   
>   #define git_SHA_CTX	blk_SHA_CTX
>   #define git_SHA1_Init	blk_SHA1_Init
> -#define git_SHA1_Update	blk_SHA1_Update
> +#define platform_SHA1_Update	blk_SHA1_Update
>   #define git_SHA1_Final	blk_SHA1_Final
> diff --git a/cache.h b/cache.h
> index 79066e5..a501652 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -10,12 +10,21 @@
>   #include "trace.h"
>   #include "string-list.h"
>   
> +// platform's underlying implementation of SHA1
Please use /* */ for comments
>   #include SHA1_HEADER
>   #ifndef git_SHA_CTX
> -#define git_SHA_CTX	SHA_CTX
> -#define git_SHA1_Init	SHA1_Init
> -#define git_SHA1_Update	SHA1_Update
> -#define git_SHA1_Final	SHA1_Final
> +#define git_SHA_CTX		SHA_CTX
> +#define git_SHA1_Init		SHA1_Init
> +#define platform_SHA1_Update	SHA1_Update
> +#define git_SHA1_Final		SHA1_Final
> +#endif
> +
> +// choose whether chunked implementation or not
> +#ifdef SHA1_MAX_BLOCK_SIZE
> +int git_SHA1_Update_Chunked(SHA_CTX *c, const void *data, size_t len);
> +#define git_SHA1_Update       git_SHA1_Update_Chunked
> +#else
> +#define git_SHA1_Update       platform_SHA1_Update
>   #endif
>   
>   #include <zlib.h>
> diff --git a/compat/apple-common-crypto.h b/compat/apple-common-crypto.h
> index c8b9b0e..d3fb264 100644
> --- a/compat/apple-common-crypto.h
> +++ b/compat/apple-common-crypto.h
> @@ -16,6 +16,10 @@
>   #undef TYPE_BOOL
>   #endif
>   
> +#ifndef SHA1_MAX_BLOCK_SIZE
> +#error Using Apple Common Crypto library requires setting SHA1_MAX_BLOCK_SIZE
> +#endif
> +
>   #ifdef APPLE_LION_OR_NEWER
>   #define git_CC_error_check(pattern, err) \
>   	do { \
> diff --git a/compat/sha1_chunked.c b/compat/sha1_chunked.c
> new file mode 100644
> index 0000000..61f67de
> --- /dev/null
> +++ b/compat/sha1_chunked.c
> @@ -0,0 +1,19 @@
> +#include "cache.h"
> +
> +int git_SHA1_Update_Chunked(SHA_CTX *c, const void *data, size_t len)
> +{
> +	size_t nr;
> +	size_t total = 0;
> +	const char *cdata = (const char*)data;
> +
> +	while (len > 0) {
size_t is unsigned, isn't it ?
Better to use  "while (len) {"
> +		nr = len;
> +		if (nr > SHA1_MAX_BLOCK_SIZE)
> +			nr = SHA1_MAX_BLOCK_SIZE;
> +		platform_SHA1_Update(c, cdata, nr);
> +		total += nr;
> +		cdata += nr;
> +		len -= nr;
> +	}
> +	return total;
> +}