From: Benjamin Kaduk <bkaduk@akamai.com>
Date: Mon, 1 Jun 2020 19:31:55 +0000 (-0700)
Subject: Allow oversized buffers for provider cipher IV fetch
X-Git-Tag: openssl-3.0.0-alpha4~64
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=7cc5e0d283800c757e46d1476273d271120aa38d;p=oweals%2Fopenssl.git

Allow oversized buffers for provider cipher IV fetch

When we're fetching an IV, there's no need to enforce that the
provided buffer is exactly the same size as the IV we want to
write into it.  This might happen, for example, when
EVP_CIPHER_CTX_iv_noconst() passes sizeof(ctx->iv) (that is,
EVP_MAX_IV_LENGTH) for an AES-GCM cipher that uses a shorter IV.
AES-OCB and CCM were also affected.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12039)
---

diff --git a/providers/implementations/ciphers/cipher_aes_ocb.c b/providers/implementations/ciphers/cipher_aes_ocb.c
index 681eb9ee70..84ba062d6b 100644
--- a/providers/implementations/ciphers/cipher_aes_ocb.c
+++ b/providers/implementations/ciphers/cipher_aes_ocb.c
@@ -401,7 +401,7 @@ static int aes_ocb_get_ctx_params(void *vctx, OSSL_PARAM params[])
 
     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IV);
     if (p != NULL) {
-        if (ctx->base.ivlen != p->data_size) {
+        if (ctx->base.ivlen > p->data_size) {
             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
             return 0;
         }
diff --git a/providers/implementations/ciphers/ciphercommon_ccm.c b/providers/implementations/ciphers/ciphercommon_ccm.c
index 3825a0741c..2b9a0687e3 100644
--- a/providers/implementations/ciphers/ciphercommon_ccm.c
+++ b/providers/implementations/ciphers/ciphercommon_ccm.c
@@ -160,7 +160,7 @@ int ccm_get_ctx_params(void *vctx, OSSL_PARAM params[])
 
     p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IV);
     if (p != NULL) {
-        if (ccm_get_ivlen(ctx) != p->data_size) {
+        if (ccm_get_ivlen(ctx) > p->data_size) {
             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IVLEN);
             return 0;
         }
diff --git a/providers/implementations/ciphers/ciphercommon_gcm.c b/providers/implementations/ciphers/ciphercommon_gcm.c
index 06fbbd07aa..7daa8dce5b 100644
--- a/providers/implementations/ciphers/ciphercommon_gcm.c
+++ b/providers/implementations/ciphers/ciphercommon_gcm.c
@@ -156,7 +156,7 @@ int gcm_get_ctx_params(void *vctx, OSSL_PARAM params[])
     if (p != NULL) {
         if (ctx->iv_gen != 1 && ctx->iv_gen_rand != 1)
             return 0;
-        if (ctx->ivlen != p->data_size) {
+        if (ctx->ivlen > p->data_size) {
             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
             return 0;
         }