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Fix ABI break with HMAC

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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: Richard Levitte <levitte@openssl.org>
This commit is contained in:
Matt Caswell 2015-06-12 13:08:04 +01:00
parent 063dccd027
commit 4b464e7b46
3 changed files with 14 additions and 14 deletions
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20
crypto/hmac/hmac.c
View File

@ -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;
}
memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);
dctx->key_length = sctx->key_length;
dctx->md = sctx->md;
return 1;
err:

1
include/openssl/hmac.h
View File

@ -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))

7
test/hmactest.c
View File

@ -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;