Correct tag len check when determining how much space we have in the pkt

If the available space is equal to the tag length then we have no available
space for plaintext data.

Fixes #22699

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22715)

diff --git a/ssl/quic/quic_record_tx.c b/ssl/quic/quic_record_tx.c
index 4f86c68e1773b558dd5ce4eb4d8c4ee0e76f4fd8..c01abed0d66a4d42d60f6bcb533a610185b43a1e 100644 (file)
--- a/ssl/quic/quic_record_tx.c
+++ b/ssl/quic/quic_record_tx.c
@@ -422,7 +422,7 @@ int ossl_qtx_calculate_plaintext_payload_len(OSSL_QTX *qtx, uint32_t enc_level,
 
     tag_len = ossl_qrl_get_suite_cipher_tag_len(el->suite_id);
 
-    if (ciphertext_len < tag_len) {
+    if (ciphertext_len <= tag_len) {
         *plaintext_len = 0;
         return 0;
     }