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 F1F91302155 for ; Thu, 17 Sep 2026 04:23:13 +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=1789618995; cv=none; b=hLpGxfcGugCPYz120DZ4rWJkmcn0q+BsdOUdj/X3HEmm2XTpyUKqFhJIWO37FloXM00ted5g5MD9RU5rfYdWej5d8/QWHk5ZubdecmZxepVdArKP95tnJrOscUMEofJCWcMJWRovQz9KuheRMJQDkGoM04kHrDJ159vJtK8EFU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789618995; c=relaxed/simple; bh=cNhKtXkjjUa6RAb7t9HmNkUtby9uqo1d/To5NJonoTs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qKPhufSmBcEKQit8fXY83A0cY58Elytg/0ToawW9LAoUalAo16n5qDJP0Td98OmeVSBZ+l+/h8oF7v2OyslnnQ2LO3X6M3OWtGkPGj1013scmPTCQWEh1O5i3wb8trY/pxMHLDyfel0iPN8pRdvFEFmwUwvJroIIFujoG6LkZbI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RycrBhDk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RycrBhDk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1BA41F00898; Thu, 17 Sep 2026 04:23:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789618993; bh=uGU5amfmd4EMWU4HOhUIpgSfvJZTqvJrONyTE8jA69w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RycrBhDk1l/+VRxS4GfY4LMA9c7ykuILlOKO+n92n8RPhwRe8S7Pbn9rCIXvZZfkX y/ALZyX1JsftA9cKUtVbZZMAwc2e09l3rldXY2yJyQ+3/gz6RjMMLx53pBH1F28FOY znCQZpPswW5erauDhOJImVpHyWPcJtKAiD6Gs7LAywcQo9SBKA/mTZdfn5jnhLU6rg Y12uxv4PGIQGs+5DEP3qv06mfwIeaJwopZguSldz79ECCUskUDeUfI6rU+EuCCGMUc zna2ZvWCkpn2nG6loJiiermhIfSZGYjoQCIWAe8+/tSqUTFmXOrdrX70VWoJGqGdKT MHMwn/RkpY62g== From: Sasha Levin To: stable@vger.kernel.org Cc: Paulo Alcantara , Namjae Jeon , Ronnie Sahlberg , Shyam Prasad N , Tom Talpey , Bharath SM , Sasha Levin Subject: [PATCH 6.18.y 2/2] smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid Date: Thu, 17 Sep 2026 00:23:10 -0400 Message-ID: <20260917042310.31062-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260917042310.31062-1-sashal@kernel.org> References: <2026091604-dehydrate-dribble-9957@gregkh> <20260917042310.31062-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Paulo Alcantara [ Upstream commit 18a72975e9f35aadecc75b031f693f2d1f49308f ] When the administrator mounts with forceuid or forcegid (uid=/gid= mount options), they expect all files to appear owned by the specified user/group. However, several code paths unconditionally called sid_to_id() to overwrite cf_uid/cf_gid with server-provided values, ignoring the administrator's explicit override: - smb311_posix_info_to_fattr() (stat via POSIX extensions) - cifs_posix_to_fattr() (readdir via POSIX extensions) - parse_sec_desc() (CIFS ACL ownership mapping) This allowed an untrusted server to dictate local file ownership even when the mount was configured to force specific uid/gid values. Fix all three call sites to check CIFS_MOUNT_OVERR_UID and CIFS_MOUNT_OVERR_GID before calling sid_to_id(), following the same pattern already used by cifs_unix_basic_to_fattr() for unix extensions. Closes: https://sashiko.dev/#/patchset/20260906155816.603278-1-pc%40manguebit.org Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin --- fs/smb/client/cifsacl.c | 29 ++++++++++++++++++----------- fs/smb/client/inode.c | 9 +++++++-- fs/smb/client/readdir.c | 9 +++++++-- 3 files changed, 32 insertions(+), 15 deletions(-) diff --git a/fs/smb/client/cifsacl.c b/fs/smb/client/cifsacl.c index 11268d10a70ed..c66bbd5606a16 100644 --- a/fs/smb/client/cifsacl.c +++ b/fs/smb/client/cifsacl.c @@ -1299,6 +1299,7 @@ static int parse_sec_desc(struct cifs_sb_info *cifs_sb, { int rc = 0; struct smb_sid *owner_sid_ptr, *group_sid_ptr; + unsigned int sbflags = cifs_sb_flags(cifs_sb); struct smb_acl *dacl_ptr; /* no need for SACL ptr */ char *end_of_acl; __u32 dacloffset, osidoffset, gsidoffset; @@ -1317,17 +1318,21 @@ static int parse_sec_desc(struct cifs_sb_info *cifs_sb, cifs_dbg(NOISY, "revision %d type 0x%x ooffset 0x%x goffset 0x%x sacloffset 0x%x dacloffset 0x%x\n", pntsd->revision, pntsd->type, osidoffset, gsidoffset, le32_to_cpu(pntsd->sacloffset), dacloffset); -/* cifs_dump_mem("owner_sid: ", owner_sid_ptr, 64); */ + fattr->cf_uid = cifs_sb->ctx->linux_uid; + fattr->cf_gid = cifs_sb->ctx->linux_gid; + rc = sid_from_sd(pntsd, acl_len, osidoffset, &owner_sid_ptr); if (rc) { cifs_dbg(FYI, "%s: Error %d parsing Owner SID\n", __func__, rc); return rc; } - rc = sid_to_id(cifs_sb, owner_sid_ptr, fattr, SIDOWNER); - if (rc) { - cifs_dbg(FYI, "%s: Error %d mapping Owner SID to uid\n", - __func__, rc); - return rc; + if (!(sbflags & CIFS_MOUNT_OVERR_UID)) { + rc = sid_to_id(cifs_sb, owner_sid_ptr, fattr, SIDOWNER); + if (rc) { + cifs_dbg(FYI, "%s: Error %d mapping Owner SID to uid\n", + __func__, rc); + return rc; + } } rc = sid_from_sd(pntsd, acl_len, gsidoffset, &group_sid_ptr); @@ -1336,11 +1341,13 @@ static int parse_sec_desc(struct cifs_sb_info *cifs_sb, __func__, rc); return rc; } - rc = sid_to_id(cifs_sb, group_sid_ptr, fattr, SIDGROUP); - if (rc) { - cifs_dbg(FYI, "%s: Error %d mapping Group SID to gid\n", - __func__, rc); - return rc; + if (!(sbflags & CIFS_MOUNT_OVERR_GID)) { + rc = sid_to_id(cifs_sb, group_sid_ptr, fattr, SIDGROUP); + if (rc) { + cifs_dbg(FYI, "%s: Error %d mapping Group SID to gid\n", + __func__, rc); + return rc; + } } if (dacloffset) { diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c index f23c36d6ae6b3..f2adac6df7b24 100644 --- a/fs/smb/client/inode.c +++ b/fs/smb/client/inode.c @@ -847,6 +847,7 @@ static void smb311_posix_info_to_fattr(struct cifs_fattr *fattr, struct smb311_posix_qinfo *info = &data->posix_fi; struct cifs_sb_info *cifs_sb = CIFS_SB(sb); struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb); + unsigned int sbflags = cifs_sb_flags(cifs_sb); memset(fattr, 0, sizeof(*fattr)); @@ -891,8 +892,12 @@ static void smb311_posix_info_to_fattr(struct cifs_fattr *fattr, fattr->cf_symlink_target = data->symlink_target; data->symlink_target = NULL; } - sid_to_id(cifs_sb, &data->posix_owner, fattr, SIDOWNER); - sid_to_id(cifs_sb, &data->posix_group, fattr, SIDGROUP); + fattr->cf_uid = cifs_sb->ctx->linux_uid; + fattr->cf_gid = cifs_sb->ctx->linux_gid; + if (!(sbflags & CIFS_MOUNT_OVERR_UID)) + sid_to_id(cifs_sb, &data->posix_owner, fattr, SIDOWNER); + if (!(sbflags & CIFS_MOUNT_OVERR_GID)) + sid_to_id(cifs_sb, &data->posix_group, fattr, SIDGROUP); cifs_dbg(FYI, "POSIX query info: mode 0x%x uniqueid 0x%llx nlink %d\n", fattr->cf_mode, fattr->cf_uniqueid, fattr->cf_nlink); diff --git a/fs/smb/client/readdir.c b/fs/smb/client/readdir.c index f0ce26622a140..93135be123316 100644 --- a/fs/smb/client/readdir.c +++ b/fs/smb/client/readdir.c @@ -242,6 +242,7 @@ static void cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info, struct cifs_sb_info *cifs_sb) { + unsigned int sbflags = cifs_sb_flags(cifs_sb); struct smb2_posix_info_parsed parsed; posix_info_parse(info, NULL, &parsed); @@ -281,8 +282,12 @@ cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info, le32_to_cpu(info->ReparseTag), le32_to_cpu(info->Mode)); - sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER); - sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP); + fattr->cf_uid = cifs_sb->ctx->linux_uid; + fattr->cf_gid = cifs_sb->ctx->linux_gid; + if (!(sbflags & CIFS_MOUNT_OVERR_UID)) + sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER); + if (!(sbflags & CIFS_MOUNT_OVERR_GID)) + sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP); } static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info) -- 2.53.0