From nobody Fri Jul 24 22:18:15 2026 Received: from mail-pj1-f45.google.com (mail-pj1-f45.google.com [209.85.216.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A880E40F72B for ; Wed, 22 Jul 2026 23:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.45 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784764754; cv=none; b=FuNUFKpupnrNxrgVUc/nz5M3VrZusFU+LHcmGdLFLIEe2DzOXAGsgtGbMe42tnshDlZdaCPyMD+TapZXdd7E1LDN/ykTzPOtoopMiDrkcQ0DqbCQh0YPcj3IcwNdXIlpdjWqOrkEH9/cvq0igHxjwEWP2VfHnzA7SyH7axfmXOM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784764754; c=relaxed/simple; bh=OwG74fSwi0W2SJ/+t1vOq0YpUMqnuUrX66aNXWCUhfE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KCykDvJ8O8QXyhOWTllrqcrmZ72vJyBrHJjxF2kFnpsx0N7gzoZpGbHlqkFgkc0SnNdKQcnXzNdho0CRgiTSTMqtUfM8QbRNYSaU8z1Bk6kIzEy0vbY4ZwLXCm5daIo9++AtJFg0z/lvbALKMBhH7wBSXkZgYdfKOZZeh43nb4w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=asu.edu; spf=pass smtp.mailfrom=asu.edu; dkim=pass (2048-bit key) header.d=asu.edu header.i=@asu.edu header.b=q6sh7B5c; arc=none smtp.client-ip=209.85.216.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=asu.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=asu.edu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=asu.edu header.i=@asu.edu header.b="q6sh7B5c" Received: by mail-pj1-f45.google.com with SMTP id 98e67ed59e1d1-38e071ed6aeso31478a91.0 for ; Wed, 22 Jul 2026 16:59:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=asu.edu; s=google; t=1784764752; x=1785369552; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=HPTrczMIYf4GzoHkfWEvB8pWP/6KobUARwbGJd0psCo=; b=q6sh7B5cBC73vZXmpkc6ld7Kp6Xdr3chkQUBIzd6bAXlo9Wi7jPuEaa0mTi90YIk5E S19sfuxGyaaResArootKorFY8AAaQJJpvFxMoE/S+xYQ4hq4QzorfSCki008lcludzv3 8R4faNqbIN0h6cT9OiL6Jvl5l34ezPg9BnrFePnhVTREx7rOBq7scB1EkVYMT05P17rU GCbjF1ygvK/F8Vl7v2cRHBbfI5kaqH14yEkMgx5CU0rOymK6swct0ktjZb4RRCvcfJGx UXD+WKKGflQAuMNOOX5UhDdyR1NopQ2HixP9CRzjTj3LZg24VVxEp6duN1RW6W1EOGzG yU3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784764752; x=1785369552; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=HPTrczMIYf4GzoHkfWEvB8pWP/6KobUARwbGJd0psCo=; b=J/FY/2IMv6xGqkDTk4LIxYWsQp5L8I9p4YmnZzD042H0Cwj5OuZOjuVlJuCQD0KoBQ j2oa4smODVbNXGQ4v8Yn/WE0zSe1O708w6AOc1g1hBeGkf7A/7HIynXxsFpljjWxS0Tt zN/vxkhKBGaMgHjJUKiiGrr9/gxQQOpT5f4PRoTgmVZx/YfUTsgbixZmtwsbhlOXfnrI cZtuFk5w6JjJNo66+y66CjbZwd4wtbdh2D8KQCl6R7gzUHxGPIn/FTnu0kDSrvbVyn8D z0Y/+AjHi5iSkUNOOrXwMBisLeGfxJsmcl8X9cCTn/k8GUrmEMUuYQj1FD7ENgvz4DpX 00RQ== X-Forwarded-Encrypted: i=1; AHgh+RpQ72LFWyrPXycgH3Wbp2H8PKNn0lEfz6JWW1f3WOpxz68KpeEVfcpAj1ZBjQufee3fCdbkqag8BCZL52c=@vger.kernel.org X-Gm-Message-State: AOJu0YyF8nAQ3oCFJAJw4REMyU5Awf0tVr8FcE7kZq/W5R6S9njF5bE9 shAgyvZ5KufomMSKRrA0Xqdy+TRTNaGcXn+2iWx27Apz4ezR48JgAhqLr+3HsSWXgg== X-Gm-Gg: AR+sD13HHcdVRzavdBrj5wwOO+KZoqKcCV7geo6DslJ8Q1vlyNdywjCSBqAo0F+hYgK 7qD84IjqjaydLNeig7TFI4PTev5Pc8QriMgsRvZ+gWlURlp8M+h8sDknEKTWi+Z7zaJ3DnbxjzL 0mQxvRc8AlFwhywUYtB3tYVKSjn8TavjgO+6y6cEXqhpPbzltbs4RwSSGeJxnuChzZ83sHiKjHV BiOlUCsdzhuBjgAkZY3GLFZn4559x6Q1eINwqJa2g8Sj39PbN9a9RlN7NaBqun8U3+mR180iq+4 NTdEzSdjtyuByUFxYH0PS7y9dMOUIkZEHdKR0kTATuwxF+YB2IlFl4/MsXTOjyaXkHM5lwJ0WZ+ pqs1RxH1ktcPwxlZwYRl18p3GGcNqCquK80GhIaPorI2Jt7+E1E75w/+XZni2uA/Io/YPY3Ague 13AAXsmOs= X-Received: by 2002:a17:90b:2d46:b0:381:a766:efc9 with SMTP id 98e67ed59e1d1-38ec6453ea7mr799849a91.7.1784764751976; Wed, 22 Jul 2026 16:59:11 -0700 (PDT) Received: from xiang.tailc0aff1.ts.net ([20.171.14.70]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13d130a87e9sm9343917c88.11.2026.07.22.16.59.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jul 2026 16:59:11 -0700 (PDT) From: "Xiang Mei (Microsoft)" To: Namjae Jeon , Steve French , Sergey Senozhatsky , Tom Talpey Cc: linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, Hyunchul Lee , Ronnie Sahlberg , AutonomousCodeSecurity@microsoft.com, tgopinath@linux.microsoft.com, kys@microsoft.com, "Xiang Mei (Microsoft)" Subject: [PATCH] ksmbd: use copied ACE count when walking DACL in set_ntacl_dacl Date: Wed, 22 Jul 2026 23:59:08 +0000 Message-ID: <20260722235908.3564560-1-xmei5@asu.edu> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" set_ntacl_dacl() copies ACEs from the stored, attacker-controlled DACL into pndace but may copy fewer than nt_num_aces (it skips ACEs with a bad sid.num_subauth and breaks on size overflow). It still passes the raw nt_num_aces to set_posix_acl_entries_dacl(), whose dedup loop then walks that many ACEs and, past the last one actually copied, reads sub_auth[num_subauth - 1] from uninitialized buffer memory - an out-of-bounds read whose offset comes from that stale byte. Pass num_aces, the count actually copied, instead. For well-formed DACLs num_aces equals nt_num_aces, so behavior is unchanged. UBSAN: array-index-out-of-bounds in fs/smb/server/smbacl.c:651:27 index -1 is out of range for type '__le32 [15]' Workqueue: ksmbd-io handle_ksmbd_work Call Trace: __ubsan_handle_out_of_bounds (lib/ubsan.c:455) set_posix_acl_entries_dacl (fs/smb/server/smbacl.c:651) build_sec_desc (fs/smb/server/smbacl.c:776 fs/smb/server/smbacl.c:1078) smb2_query_info (fs/smb/server/smb2pdu.c:6269 fs/smb/server/smb2pdu.c:63= 39) handle_ksmbd_work (fs/smb/server/server.c:308) process_one_work (kernel/workqueue.c:3322) worker_thread (kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Reported-by: AutonomousCodeSecurity@microsoft.com Signed-off-by: Xiang Mei (Microsoft) --- fs/smb/server/smbacl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c index 67b39b4d218c..957547157ef8 100644 --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -774,7 +774,7 @@ static void set_ntacl_dacl(struct mnt_idmap *idmap, } =20 set_posix_acl_entries_dacl(idmap, pndace, fattr, - &num_aces, &size, nt_num_aces); + &num_aces, &size, num_aces); pndacl->num_aces =3D cpu_to_le16(num_aces); pndacl->size =3D cpu_to_le16(le16_to_cpu(pndacl->size) + size); } --=20 2.43.0