From: Matt Caswell <matt@openssl.org>
Date: Thu, 19 Jan 2023 11:59:44 +0000 (+0000)
Subject: Ensure our buffer allocation allows for the Explicit IV
X-Git-Tag: OpenSSL_1_1_1t~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4b5ec7c560717ac90b4b05b123e6fe8ab9e20b41;p=thirdparty%2Fopenssl.git

Ensure our buffer allocation allows for the Explicit IV

Some ciphers/protocol versions have an explicit IV. We need to make sure we
have sufficient room for it in the underlying buffer.

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20087)
---

diff --git a/ssl/record/ssl3_buffer.c b/ssl/record/ssl3_buffer.c
index b9ba25e0c3f..5f40046f57c 100644
--- a/ssl/record/ssl3_buffer.c
+++ b/ssl/record/ssl3_buffer.c
@@ -97,11 +97,16 @@ int ssl3_setup_write_buffer(SSL *s, size_t numwpipes, size_t len)
 #endif
 
         len = ssl_get_max_send_fragment(s)
-            + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD + headerlen + align;
+            + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD + headerlen + align
+            + SSL_RT_MAX_CIPHER_BLOCK_SIZE /* Explicit IV allowance */;
 #ifndef OPENSSL_NO_COMP
         if (ssl_allow_compression(s))
             len += SSL3_RT_MAX_COMPRESSED_OVERHEAD;
 #endif
+        /*
+         * We don't need to add an allowance for eivlen here since empty
+         * fragments only occur when we don't have an explicit IV
+         */
         if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS))
             len += headerlen + align + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD;
     }