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 6777A47A871 for ; Thu, 17 Sep 2026 13:03:54 +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=1789650240; cv=none; b=ktcQMSfC4rUprqiDrSrJcN0xAJuxYSvIG+Y9pZh8t9v5dY5IFXgXMxNjYBr7/yaGl65LlN//ebr5OK4KBpEPVh5zPESK13i4o1MYNuvN2mPY2QYRKPoc6aJ5ZlZJy+rwUWyxAybQcmW95WVMFlv9WRAvGT8JPHltAInQgH1jGBE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789650240; c=relaxed/simple; bh=X8ctYp5ZJYuGjFUI7ITrmZD0Q3yoTPGo4zABP/o1iNI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XriNyBxx9d5gYF4teRLmjNe2GHkZT88xiQQaHS6phJBzqGShJfznZSOC47+nCP05tiqvKZZIvUN3nQixgynTsrCV83bOSqra5CdZGt0eu2dS5wsCgiivH2U8nZ5g0nCN2uP9L6BI6Fz7SOiclv74EEfN9ZIV29s3wySe6yIhozY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HBjzxc7b; 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="HBjzxc7b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 958491F0089B; Thu, 17 Sep 2026 13:03:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789650231; bh=1efO0SSbNLry/ev/LAcRYuxtFesSKB5awTrnrAIFBbc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HBjzxc7brz6v6TdHQcdomPkPkZSM2eqpZ6WHvwEZgC1Vf7kfK7PPTYIPGBS3bw9fW 9xfdN3faqNeKOlDzU0no/X6rjnxJa4Gw4KCTAGYP/OpofQ5yLlavmATfYLTar4JT/s gFq8E9v0j0qzXcCrJBy3izTklgmQL0jNmHb14iwtKPw5d8dzM3/1r9gr3KzSaXHjUy Ke0VAU2u1rK+/3xarvlqBWAeVZI438nsD2tenhs1C9rwuFxuKJGbUzqwNtBYsBx4Wa 67MNsN0SyIyvAuXqaQtSD2esj39O2AQJXeQtoDMUoVgmoUe0q2zgfkqAykcp13ckCe fEd2GEOXp5nzQ== 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 6.6.y 2/2] smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid Date: Thu, 17 Sep 2026 09:03:48 -0400 Message-ID: <20260917130348.320328-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260917130348.320328-1-sashal@kernel.org> References: <2026091605-runaround-justness-9c84@gregkh> <20260917130348.320328-1-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 af6f746f68256..97c02467596be 100644 --- a/fs/smb/client/cifsacl.c +++ b/fs/smb/client/cifsacl.c @@ -1300,6 +1300,7 @@ 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; @@ -1318,17 +1319,21 @@ 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); @@ -1337,11 +1342,13 @@ 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 cca480ab7e64b..545c6b09cb73c 100644 --- a/fs/smb/client/inode.c +++ b/fs/smb/client/inode.c @@ -770,6 +770,7 @@ 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)); @@ -814,8 +815,12 @@ 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 5febf8afaab04..8ccfdc6a10cfb 100644 --- a/fs/smb/client/readdir.c +++ b/fs/smb/client/readdir.c @@ -241,6 +241,7 @@ 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); @@ -280,8 +281,12 @@ 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