From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93C3C51AECC; Wed, 30 Sep 2026 17:58:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791137; cv=none; b=t8zhpNCw/oCTL5J89UlZBThccY6oPafpRoB7hEZin/Orwe/YJ0eOjXg4s2ClBjzXn83HjHzkK0TqHe3HOp/um9IMa6zSm+N2Fum7clU5GgU4gspn1QyTPqYmkOMeMhxs2ZCkmCqyAn4mgvxegyhx7kcCAAiVNUga54B0ejRwKSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791137; c=relaxed/simple; bh=M6oQG8OTL61rJb+TSeooEPUyZ2J3PgpFJpn/dHuT1NE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=j3GzpinaNxruBsTEQqWNs4HoISKN3DYkW74xdMBnf+shUvy2gDEwU+YNdGATP439bhw8eRUCs8zuzfcVo9EYnfw+Te3pB5zeVVCkVfTKWIGkKNHsXgdfkm6wV6mM7Trptz853E1azfwgKqIaXFdWx+pxJ0Lbnkp6s3Fe9s5orPU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HxqtCObL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HxqtCObL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBF841F00898; Wed, 30 Sep 2026 17:58:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791136; bh=3IY3d3EKv7giEqnVb29iqkYqcTO0Y/zBDKXtl8IB0+Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HxqtCObLsnbnBbyKo7XdZgU/nC5yCkXA7hwMbuHsX3e0vS+vtXBAJ88yf5LEl1zTY 1AkpJsY02Fu+25cCxTvmTNmNXE3Nx+wcfsXdXZM3IKwFZnZBNPD9gvjnuBid/p+b9v 46FykATFxC6/hWsFh8HPeJ2T+4o38UXTD/kJh5oU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Namjae Jeon , Steve French , Sasha Levin Subject: [PATCH 5.15 197/752] ksmbd: validate SID namespace before mapping IDs Date: Wed, 30 Sep 2026 17:21:07 +0200 Message-ID: <20260930152402.481160823@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Namjae Jeon [ Upstream commit fbe0bb2b75eb3c61e8464486506253d1b471240b ] sid_to_id() currently treats the last subauthority of any owner or group SID as a Unix uid or gid. For example, this maps Everyone (S-1-1-0) to uid 0 and BUILTIN\Users (S-1-5-32-545) to gid 545. When an SMB2 CREATE security descriptor contains those SIDs, ksmbd attempts to change the newly created file to the bogus Unix ownership. notify_change() then returns -EPERM, which makes smb2.create.aclfile fail with NT_STATUS_SHARING_VIOLATION. Validate the SID prefix before extracting its RID. Only server-domain owner SIDs and S-1-22-2 Unix group SIDs have local ID representations. Treat other valid Windows SIDs as unmapped so their original values can still be preserved in the NT ACL xattr. Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/ksmbd/smbacl.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c index 0697574017e9d..a41964531c3ca 100644 --- a/fs/ksmbd/smbacl.c +++ b/fs/ksmbd/smbacl.c @@ -259,6 +259,7 @@ static int sid_to_id(struct user_namespace *user_ns, struct smb_sid *psid, uint sidtype, struct smb_fattr *fattr) { + const struct smb_sid *sid_prefix; int rc = -EINVAL; /* @@ -275,6 +276,12 @@ static int sid_to_id(struct user_namespace *user_ns, kuid_t uid; uid_t id; + /* Only the server domain RID has a local uid representation. */ + sid_prefix = &server_conf.domain_sid; + if (psid->num_subauth != sid_prefix->num_subauth + 1 || + compare_sids(psid, sid_prefix)) + return -EINVAL; + id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]); uid = mapped_kuid_user(user_ns, &init_user_ns, KUIDT_INIT(id)); if (uid_valid(uid)) { @@ -285,6 +292,12 @@ static int sid_to_id(struct user_namespace *user_ns, kgid_t gid; gid_t id; + /* Local gids are represented by S-1-22-2-. */ + sid_prefix = &sid_unix_groups; + if (psid->num_subauth != sid_prefix->num_subauth + 1 || + compare_sids(psid, sid_prefix)) + return -EINVAL; + id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]); gid = mapped_kgid_user(user_ns, &init_user_ns, KGIDT_INIT(id)); if (gid_valid(gid)) { @@ -858,9 +871,9 @@ int parse_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd, rc = sid_to_id(user_ns, owner_sid_ptr, SIDOWNER, fattr); if (rc) { - pr_err("%s: Error %d mapping Owner SID to uid\n", - __func__, rc); + ksmbd_debug(SMB, "Owner SID has no Unix uid mapping\n"); owner_sid_ptr = NULL; + rc = 0; } } @@ -873,9 +886,9 @@ int parse_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd, } rc = sid_to_id(user_ns, group_sid_ptr, SIDUNIX_GROUP, fattr); if (rc) { - pr_err("%s: Error %d mapping Group SID to gid\n", - __func__, rc); + ksmbd_debug(SMB, "Group SID has no Unix gid mapping\n"); group_sid_ptr = NULL; + rc = 0; } } -- 2.53.0