Commit 4b464e7b authored by Matt Caswell's avatar Matt Caswell
Browse files

Fix ABI break with HMAC 



Recent HMAC changes broke ABI compatibility due to a new field in HMAC_CTX.
This backs that change out, and does it a different way.

Thanks to Timo Teras for the concept.

Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
parent 063dccd0

crypto/hmac/hmac.c

+8 −12
Original line number Diff line number Diff line
@@ -68,6 +68,10 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, 
    int i, j, reset = 0;

    unsigned char pad[HMAC_MAX_MD_CBLOCK];



    /* If we are changing MD then we must have a key */

    if (md != NULL && md != ctx->md && (key == NULL || len < 0))

        return 0;



    if (md != NULL) {

        reset = 1;

        ctx->md = md;
@@ -77,9 +81,6 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, 
        return 0;

    }



    if (!ctx->key_init && key == NULL)

        return 0;



    if (key != NULL) {

        reset = 1;

        j = M_EVP_MD_block_size(md);
@@ -101,7 +102,6 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, 
        if (ctx->key_length != HMAC_MAX_MD_CBLOCK)

            memset(&ctx->key[ctx->key_length], 0,

                   HMAC_MAX_MD_CBLOCK - ctx->key_length);

        ctx->key_init = 1;

    }



    if (reset) {
@@ -137,7 +137,7 @@ int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md) 


int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)

{

    if (!ctx->key_init)

    if (!ctx->md)

        return 0;

    return EVP_DigestUpdate(&ctx->md_ctx, data, len);

}
@@ -147,7 +147,7 @@ int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len) 
    unsigned int i;

    unsigned char buf[EVP_MAX_MD_SIZE];



    if (!ctx->key_init)

    if (!ctx->md)

        goto err;



    if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
@@ -168,7 +168,6 @@ void HMAC_CTX_init(HMAC_CTX *ctx) 
    EVP_MD_CTX_init(&ctx->i_ctx);

    EVP_MD_CTX_init(&ctx->o_ctx);

    EVP_MD_CTX_init(&ctx->md_ctx);

    ctx->key_init = 0;

    ctx->md = NULL;

}
@@ -181,11 +180,8 @@ int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx) 
        goto err;

    if (!EVP_MD_CTX_copy_ex(&dctx->md_ctx, &sctx->md_ctx))

        goto err;

    dctx->key_init = sctx->key_init;

    if (sctx->key_init) {

    memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);

    dctx->key_length = sctx->key_length;

    }

    dctx->md = sctx->md;

    return 1;

 err:

include/openssl/hmac.h

+0 −1
Original line number Diff line number Diff line
@@ -75,7 +75,6 @@ typedef struct hmac_ctx_st { 
    EVP_MD_CTX o_ctx;

    unsigned int key_length;

    unsigned char key[HMAC_MAX_MD_CBLOCK];

    int key_init;

} HMAC_CTX;



# define HMAC_size(e)    (EVP_MD_size((e)->md))

test/hmactest.c

+6 −1
Original line number Diff line number Diff line
@@ -226,7 +226,12 @@ test5: 
        err++;

        goto test6;

    }

    if (!HMAC_Init_ex(&ctx, NULL, 0, EVP_sha256(), NULL)) {

    if (HMAC_Init_ex(&ctx, NULL, 0, EVP_sha256(), NULL)) {

        printf("Should disallow changing MD without a new key (test 5)\n");

        err++;

        goto test6;

    }

    if (!HMAC_Init_ex(&ctx, test[4].key, test[4].key_len, EVP_sha256(), NULL)) {

        printf("Failed to reinitialise HMAC (test 5)\n");

        err++;

        goto test6;