CODEWITHSUNDEEP
opensslsha
smoking gun
smoking gun

Reputation: 73

where is SHA1_Init implementation in openssl

I would like to find the implementation of SHA1_Init in openssl source code.

http://osxr.org:8080/openssl/source/crypto/sha/sha1.c#0108

0108     SHA1_Init(&c);

but only definition found in http://osxr.org:8080/openssl/source/crypto/sha/sha.h#0122

Where is it? Thanks,

=SG=

Upvotes: 4

Views: 1788

Answers (2)

VonC
VonC

Reputation: 1327784

Note: starting with Git 2.42 (Q3 2023), you would no longer find SHA1_Init(&c) used: Git 2.42 adjusts to OpenSSL 3+, which deprecates its SHA-1 functions based on its traditional API, by using its EVP API instead.

See "What does OpenSSL's EVP (Envelope Cryptography) mean?", and "Encrypting/Decrypting a file using OpenSSL EVP" by Amit Kulkarni.

See commit bda9c12, commit 3e440ea (01 Aug 2023) by Eric Wong (ele828).
(Merged by Junio C Hamano -- gitster -- in commit 889c94d, 09 Aug 2023)

bda9c12073:avoid SHA-1 functions deprecated in OpenSSL 3+

Signed-off-by: Eric Wong

OpenSSL 3+ deprecates the SHA1_Init, SHA1_Update, and SHA1_Final functions, leading to errors when building with `DEVELOPER=1'.

Use the newer EVP_* API with OpenSSL 3+ (only) despite being more error-prone and less efficient due to heap allocations.

For instance, you would now have, instead of using directly SHA1_Init(&c):

static inline void openssl_SHA1_Init(struct openssl_SHA1_CTX *ctx)
{
    const EVP_MD *type = EVP_sha1();

    ctx->ectx = EVP_MD_CTX_new();
    if (!ctx->ectx)
        die("EVP_MD_CTX_new: out of memory");

    EVP_DigestInit_ex(ctx->ectx, type, NULL);
}

With EVP_DigestInit_ex() being defined in openssl/openssl crypto/evp/digest.c

Upvotes: 0

winhowes
winhowes

Reputation: 8065

So SHA1_Init is defined in the header of sha_locl.h as HASH_INIT. sha1dgst.c includes sha_locl.h which includes ../md32_common.h which does the expansion of HASH_UPDATE, HASH_TRANFORM, and HASH_FINAL which is defined as SHA1_Init in sha.h. I believe the actual implementation though of SHA1_Init is ultimately here: http://osxr.org:8080/openssl/source/crypto/sha/sha_locl.h#0125 or here on github: https://github.com/openssl/openssl/blob/master/crypto/sha/sha_locl.h#L101.

Upvotes: 1

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