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 4A5E553D9EE; Thu, 17 Sep 2026 17:07:00 +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=1789664821; cv=none; b=K7SjGlLByPqBPOi13a2doyWWzAW8mniraygjvaivsb2f5bJ9brd7eGeDWsL/enSeghIvfskQI2IlhWWfyxbZ9YDgNaEkvrmnfZ8o1iwbD3GfFQkoMqiVMyEVnlCPIet3+sWJ/0tjFqo4ExJ0egUVogRRmR/6WdQ74cBwMCwa1Lg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789664821; c=relaxed/simple; bh=9HrkOqLnkYjSdI5apmBhQ3WoKUsPV11xj+TJT3BDTYw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=awHbGTWgn15SW0edL9+c1TMVatTirGlWif4QGlPyJUcrJXJVbHQJOCylY7UZABit1S/inuEhK+rgxXAtd55b7LUuZjO2clXoWao0AnBIMysYrLmaFmYNOY4WuMqxfW8UY0m/Phmixl9KgK9yOFG48t0+ygc5u5ais/BUSRz7j6E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Bceo9Mvv; 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="Bceo9Mvv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B3A91F000FF; Thu, 17 Sep 2026 17:06:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789664820; bh=lynKm52Wo6qwDSOr/uV2jAb2mngY5RlPtHAW2oKiCVo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Bceo9MvvjpyNX0z5LSaGIeIjyI12TMEg3SYoakU6jjDyiM2focPzQsSBdTztGJx9E sOZG3LLKKdgxz5eNOtj7+DcIOAoViDOKfaod1sqPrwCFO7MGpIaQanZyxAXEvQyS2p 0qW5vOL3cYlW8cJZCKJei2C/HkTphFDuFh98DbUc= 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 6.18 0499/1250] ksmbd: validate SID namespace before mapping IDs Date: Thu, 17 Sep 2026 16:04:54 +0100 Message-ID: <20260917151605.487169369@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151551.901433442@linuxfoundation.org> References: <20260917151551.901433442@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 6.18-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