From b3f0eb0a295f58f16ba43ba99dad70d4ee5c437d Mon Sep 17 00:00:00 2001 From: Watson Ladd Date: Wed, 24 Apr 2024 11:26:56 +0100 Subject: [PATCH] Only free the read buffers if we're not using them If we're part way through processing a record, or the application has not released all the records then we should not free our buffer because they are still needed. CVE-2024-4741 Reviewed-by: Tomas Mraz Reviewed-by: Neil Horman Reviewed-by: Matt Caswell (Merged from https://github.com/openssl/openssl/pull/24395) (cherry picked from commit 704f725b96aa373ee45ecfb23f6abfe8be8d9177) --- ssl/record/rec_layer_s3.c | 9 +++++++++ ssl/record/record.h | 1 + ssl/ssl_lib.c | 3 +++ 3 files changed, 13 insertions(+) diff --git a/ssl/record/rec_layer_s3.c b/ssl/record/rec_layer_s3.c index 4bcffcc41e364..1569997bea2d3 100644 --- ssl/record/rec_layer_s3.c.orig +++ ssl/record/rec_layer_s3.c @@ -81,6 +81,15 @@ int RECORD_LAYER_read_pending(const RECORD_LAYER *rl) return SSL3_BUFFER_get_left(&rl->rbuf) != 0; } +int RECORD_LAYER_data_present(const RECORD_LAYER *rl) +{ + if (rl->rstate == SSL_ST_READ_BODY) + return 1; + if (RECORD_LAYER_processed_read_pending(rl)) + return 1; + return 0; +} + /* Checks if we have decrypted unread record data pending */ int RECORD_LAYER_processed_read_pending(const RECORD_LAYER *rl) { diff --git a/ssl/record/record.h b/ssl/record/record.h index 234656bf93942..b60f71c8cb23b 100644 --- ssl/record/record.h.orig +++ ssl/record/record.h @@ -205,6 +205,7 @@ void RECORD_LAYER_release(RECORD_LAYER *rl); int RECORD_LAYER_read_pending(const RECORD_LAYER *rl); int RECORD_LAYER_processed_read_pending(const RECORD_LAYER *rl); int RECORD_LAYER_write_pending(const RECORD_LAYER *rl); +int RECORD_LAYER_data_present(const RECORD_LAYER *rl); void RECORD_LAYER_reset_read_sequence(RECORD_LAYER *rl); void RECORD_LAYER_reset_write_sequence(RECORD_LAYER *rl); int RECORD_LAYER_is_sslv2_record(RECORD_LAYER *rl); diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c index eed649c6fdee9..d14c55ae557bc 100644 --- ssl/ssl_lib.c.orig +++ ssl/ssl_lib.c @@ -5492,6 +5492,9 @@ int SSL_free_buffers(SSL *ssl) if (RECORD_LAYER_read_pending(rl) || RECORD_LAYER_write_pending(rl)) return 0; + if (RECORD_LAYER_data_present(rl)) + return 0; + RECORD_LAYER_release(rl); return 1; }