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Fix a leak in EVP_DigestInit_ex()

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If an EVP_MD_CTX is reused then memory allocated and stored in md_data
can be leaked unless the EVP_MD's cleanup function is called.

Fixes #17149

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/17255)
This commit is contained in:
Matt Caswell 2021-12-10 17:17:27 +00:00
parent d9ad5b16b3
commit 357bccc8ba
1 changed files with 17 additions and 14 deletions
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31
crypto/evp/digest.c
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@ -25,6 +25,19 @@
#include "crypto/evp.h"
#include "evp_local.h"
static void cleanup_old_md_data(EVP_MD_CTX *ctx, int force)
{
if (ctx->digest != NULL) {
if (ctx->digest->cleanup != NULL
&& !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_CLEANED))
ctx->digest->cleanup(ctx);
if (ctx->md_data != NULL && ctx->digest->ctx_size > 0
&& (!EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_REUSE)
|| force))
OPENSSL_clear_free(ctx->md_data, ctx->digest->ctx_size);
ctx->md_data = NULL;
}
}
void evp_md_ctx_clear_digest(EVP_MD_CTX *ctx, int force)
{
@ -41,12 +54,7 @@ void evp_md_ctx_clear_digest(EVP_MD_CTX *ctx, int force)
* Don't assume ctx->md_data was cleaned in EVP_Digest_Final, because
* sometimes only copies of the context are ever finalised.
*/
if (ctx->digest && ctx->digest->cleanup
&& !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_CLEANED))
ctx->digest->cleanup(ctx);
if (ctx->digest && ctx->digest->ctx_size && ctx->md_data
&& (!EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_REUSE) || force))
OPENSSL_clear_free(ctx->md_data, ctx->digest->ctx_size);
cleanup_old_md_data(ctx, force);
if (force)
ctx->digest = NULL;
@ -217,10 +225,7 @@ static int evp_md_init_internal(EVP_MD_CTX *ctx, const EVP_MD *type,
goto legacy;
}
if (ctx->digest != NULL && ctx->digest->ctx_size > 0) {
OPENSSL_clear_free(ctx->md_data, ctx->digest->ctx_size);
ctx->md_data = NULL;
}
cleanup_old_md_data(ctx, 1);
/* Start of non-legacy code below */
@ -309,10 +314,8 @@ static int evp_md_init_internal(EVP_MD_CTX *ctx, const EVP_MD *type,
}
#endif
if (ctx->digest != type) {
if (ctx->digest && ctx->digest->ctx_size) {
OPENSSL_clear_free(ctx->md_data, ctx->digest->ctx_size);
ctx->md_data = NULL;
}
cleanup_old_md_data(ctx, 1);
ctx->digest = type;
if (!(ctx->flags & EVP_MD_CTX_FLAG_NO_INIT) && type->ctx_size) {
ctx->update = type->update;