From 1a556ff619473af9e179b202284a961590d5a2bd Mon Sep 17 00:00:00 2001
From: Norbert Pocs <norbertp@openssl.org>
Date: Thu, 8 Jan 2026 15:04:54 +0100
Subject: [PATCH] Fix OCB AES-NI/HW stream path unauthenticated/unencrypted
 trailing bytes
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When ctx->stream (e.g., AES‑NI or ARMv8 CE) is available, the fast path
encrypts/decrypts full blocks but does not advance in/out pointers. The
tail-handling code then operates on the base pointers, effectively reprocessing
the beginning of the buffer while leaving the actual trailing bytes
unencrypted (encryption) or using the wrong plaintext (decryption). The
authentication checksum excludes the true tail.

CVE-2025-69418

Fixes: https://github.com/openssl/srt/issues/58

Signed-off-by: Norbert Pocs <norbertp@openssl.org>
---
 crypto/modes/ocb128.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/crypto/modes/ocb128.c b/crypto/modes/ocb128.c
index ce72baf6da5..8a5d7c7db00 100644
--- a/crypto/modes/ocb128.c
+++ b/crypto/modes/ocb128.c
@@ -337,7 +337,7 @@ int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx,
 
     if (num_blocks && all_num_blocks == (size_t)all_num_blocks
         && ctx->stream != NULL) {
-        size_t max_idx = 0, top = (size_t)all_num_blocks;
+        size_t max_idx = 0, top = (size_t)all_num_blocks, processed_bytes = 0;
 
         /*
          * See how many L_{i} entries we need to process data at hand
@@ -351,6 +351,9 @@ int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx,
         ctx->stream(in, out, num_blocks, ctx->keyenc,
                     (size_t)ctx->sess.blocks_processed + 1, ctx->sess.offset.c,
                     (const unsigned char (*)[16])ctx->l, ctx->sess.checksum.c);
+        processed_bytes = num_blocks * 16;
+        in += processed_bytes;
+        out += processed_bytes;
     } else {
         /* Loop through all full blocks to be encrypted */
         for (i = ctx->sess.blocks_processed + 1; i <= all_num_blocks; i++) {
@@ -429,7 +432,7 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx,
 
     if (num_blocks && all_num_blocks == (size_t)all_num_blocks
         && ctx->stream != NULL) {
-        size_t max_idx = 0, top = (size_t)all_num_blocks;
+        size_t max_idx = 0, top = (size_t)all_num_blocks, processed_bytes = 0;
 
         /*
          * See how many L_{i} entries we need to process data at hand
@@ -443,6 +446,9 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx,
         ctx->stream(in, out, num_blocks, ctx->keydec,
                     (size_t)ctx->sess.blocks_processed + 1, ctx->sess.offset.c,
                     (const unsigned char (*)[16])ctx->l, ctx->sess.checksum.c);
+        processed_bytes = num_blocks * 16;
+        in += processed_bytes;
+        out += processed_bytes;
     } else {
         OCB_BLOCK tmp;
 
