From cf55ce42d0268f9cfd7abc43aa4ec62d2e8c3f53 Mon Sep 17 00:00:00 2001
Message-ID: <cf55ce42d0268f9cfd7abc43aa4ec62d2e8c3f53.1788185282.git.sam@gentoo.org>
From: NIIBE Yutaka <gniibe@fsij.org>
Date: Thu, 27 Aug 2026 13:47:19 +0900
Subject: [PATCH 1/3] cipher:rsa:oaep: Validate all-zero PS.

* cipher/rsa-common.c (_gcry_rsa_oaep_decode): Reject non-zero PS.

--

GnuPG-bug-id: 8390
Reported-by: JEAN Jeremy <Jeremy.Jean@ssi.gouv.fr>
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
---
 cipher/rsa-common.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cipher/rsa-common.c b/cipher/rsa-common.c
index 1c36c912..f8d06c72 100644
--- a/cipher/rsa-common.c
+++ b/cipher/rsa-common.c
@@ -755,6 +755,7 @@ _gcry_rsa_oaep_decode (unsigned char **r_result, size_t *r_resultlen,
     {
       not_found &= ct_not_equal_byte (db[n], 0x01);
       n1 += not_found;
+      failed |= (not_found & ct_not_equal_byte (db[n], 0x00));
     }
   failed |= not_found;
   failed |= ct_not_equal_byte (frame[0], 0x00);
-- 
2.55.0