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 A93C33B71AC; Thu, 17 Sep 2026 18:05:50 +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=1789668351; cv=none; b=ucJ2eD/JHeADhAht2ruF+svifjVdMVWQAb83M80uXfqfUneRODsArz49M95cvz3BXIylsHZi+6miYgZS0UBck4SWMUgpUpgabeRDW73xjGsHvUqPVh9/zQXaCaNg72ZZafFJW8mMdcbvv6LfBN0rvyeQwiCZDVIE0wuSRNnPl9U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789668351; c=relaxed/simple; bh=90KuQg11BEZbDcbf1+1K3ExceoSDC1IRtNPHsm0Xnnc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eTgaf3EFZNrZPWkQ2uLSZmeyqbwBRUO3jeb5zabc1viNaHxtAMIpfk+9c5csaYKVJA92MSdNmRevXRw9pQPeGGzf+7+2W4/emnytw8KkofJsGjjRQaRD6LSM65sQCA1hQAE0nLhDkBjfVI6XGQYGiJYn2GjDn1x7u8xQ+31w3o8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Q2OV9/xm; 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="Q2OV9/xm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E6591F000FF; Thu, 17 Sep 2026 18:05:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789668350; bh=A7h4XU+yfO4TLod5t/Ttr+Qh00Z6iTX/nm/oUu44T2A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Q2OV9/xmqNE3i/bVTsOos1myK9dbc5b8RzSjJrIuvfoL9ReNHo/JZq8R8VeKTngsI ymSyUU401w8nYltyGD0Dcpd1xhQuNjjC2NCg0ltKpTtVDVmIwPSK2P3JXgu0E17nRH uNu0ZwsUsO4TFHcXi8C43DAen1oWcOg5vLiYSOss= 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 6.12 0395/1102] ksmbd: validate SID namespace before mapping IDs Date: Thu, 17 Sep 2026 16:05:38 +0100 Message-ID: <20260917151549.574845403@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151539.408551884@linuxfoundation.org> References: <20260917151539.408551884@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 6.12-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/smb/server/smbacl.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c index 0879012aa63c8..3586a6025127e 100644 --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -258,6 +258,7 @@ static int sid_to_id(struct mnt_idmap *idmap, struct smb_sid *psid, uint sidtype, struct smb_fattr *fattr) { + const struct smb_sid *sid_prefix; int rc = -EINVAL; /* @@ -279,6 +280,12 @@ static int sid_to_id(struct mnt_idmap *idmap, 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 = KUIDT_INIT(id); uid = from_vfsuid(idmap, &init_user_ns, VFSUIDT_INIT(uid)); @@ -290,6 +297,12 @@ static int sid_to_id(struct mnt_idmap *idmap, 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 = KGIDT_INIT(id); gid = from_vfsgid(idmap, &init_user_ns, VFSGIDT_INIT(gid)); @@ -916,9 +929,9 @@ int parse_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd, rc = sid_to_id(idmap, 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; } } @@ -934,9 +947,9 @@ int parse_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd, } rc = sid_to_id(idmap, 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