| Message ID | e7cd23bf4cd232fa2ce610284199996383fb3323.1725206584.git.me@ttaylorr.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | hash.h: support choosing a separate SHA-1 for non-cryptographic uses | expand |
On Sun, Sep 01, 2024 at 12:03:21PM -0400, Taylor Blau wrote: > Our in-tree SHA-1 wrappers all define platform_SHA_CTX and related > macros to point at the opaque "context" type, init, update, and similar > functions for each specific implementation. > > In hash.h, we use these platform_ variables to set up the function > pointers for, e.g., the_hash_algo->init_fn(), etc. > > But while these header files have a header-specific macro that prevents > them declaring their structs / functions multiple times, they > unconditionally define the platform variables, making it impossible to > load multiple SHA-1 implementations at once. > > As a prerequisite for loading a separate SHA-1 implementation for > non-cryptographic uses, only define the platform_ variables if they have > not already been defined. So we now pick the first hash we find as platform hash, whereas previously we would have always picked the last one? Hum, okay. A bit curious, but let's read on. Patrick
On Mon, Sep 02, 2024 at 03:41:20PM +0200, Patrick Steinhardt wrote: > So we now pick the first hash we find as platform hash, whereas > previously we would have always picked the last one? Hum, okay. A bit > curious, but let's read on. In a pre-_FAST SHA-1 environment, we only ever #include one of these to begin with, so the order doesn't matter. After this series, we may include two SHA-1 implementations, but we include the non-_FAST one first, so we'll always pick that one as the default platform implementation. Thanks, Taylor
diff --git a/block-sha1/sha1.h b/block-sha1/sha1.h index 9fb0441b988..47bb9166368 100644 --- a/block-sha1/sha1.h +++ b/block-sha1/sha1.h @@ -16,7 +16,9 @@ void blk_SHA1_Init(blk_SHA_CTX *ctx); void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *dataIn, size_t len); void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx); +#ifndef platform_SHA_CTX #define platform_SHA_CTX blk_SHA_CTX #define platform_SHA1_Init blk_SHA1_Init #define platform_SHA1_Update blk_SHA1_Update #define platform_SHA1_Final blk_SHA1_Final +#endif diff --git a/sha1/openssl.h b/sha1/openssl.h index 006c1f4ba54..1038af47daf 100644 --- a/sha1/openssl.h +++ b/sha1/openssl.h @@ -40,10 +40,12 @@ static inline void openssl_SHA1_Clone(struct openssl_SHA1_CTX *dst, EVP_MD_CTX_copy_ex(dst->ectx, src->ectx); } +#ifndef platform_SHA_CTX #define platform_SHA_CTX openssl_SHA1_CTX #define platform_SHA1_Init openssl_SHA1_Init #define platform_SHA1_Clone openssl_SHA1_Clone #define platform_SHA1_Update openssl_SHA1_Update #define platform_SHA1_Final openssl_SHA1_Final +#endif #endif /* SHA1_OPENSSL_H */ diff --git a/sha1dc_git.h b/sha1dc_git.h index 60e3ce84395..f6f880cabea 100644 --- a/sha1dc_git.h +++ b/sha1dc_git.h @@ -18,7 +18,10 @@ void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *); void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, unsigned long len); #define platform_SHA_IS_SHA1DC /* used by "test-tool sha1-is-sha1dc" */ + +#ifndef platform_SHA_CTX #define platform_SHA_CTX SHA1_CTX #define platform_SHA1_Init git_SHA1DCInit #define platform_SHA1_Update git_SHA1DCUpdate #define platform_SHA1_Final git_SHA1DCFinal +#endif
Our in-tree SHA-1 wrappers all define platform_SHA_CTX and related macros to point at the opaque "context" type, init, update, and similar functions for each specific implementation. In hash.h, we use these platform_ variables to set up the function pointers for, e.g., the_hash_algo->init_fn(), etc. But while these header files have a header-specific macro that prevents them declaring their structs / functions multiple times, they unconditionally define the platform variables, making it impossible to load multiple SHA-1 implementations at once. As a prerequisite for loading a separate SHA-1 implementation for non-cryptographic uses, only define the platform_ variables if they have not already been defined. Signed-off-by: Taylor Blau <me@ttaylorr.com> --- block-sha1/sha1.h | 2 ++ sha1/openssl.h | 2 ++ sha1dc_git.h | 3 +++ 3 files changed, 7 insertions(+)