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 5AEBA511E69; Thu, 17 Sep 2026 15:56:22 +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=1789660583; cv=none; b=b4ud9uACHKTNlTC9iJSk/kaRUZxXvF+G2iup8f/817i5uNDaU7Zu4HjDGWAhpWHqGTfNk3yeNmEa8to0vF3P0So4zk1C7d8HhN9iHMOPd9obDLpclvE9VxJ25VVFQ8/7Uz06k7vchdZgxFA+XO0e0svQ4w96y2UrgWCCI4l41qc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660583; c=relaxed/simple; bh=YhYE3pXbbNVSTYPz8ZFGAm7Oba+qQQfrE7L0JQs5Ezo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mbMXp0GLZRFGX923Ge9APW0hjzWT60FtfxyydQ95azrQITZDzBtZOmt7RjRr2ALDFrLdVyWOm7iQTQDlNi8d/HSlx9z7UDj4uxZoDL/R3lA3bffeDrFcqXUj02nqXGbtjOKKSAIkSwgMOFr3L4UFHfHbIJWkapcrYVo1AuHQH5U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=N/HAPMlW; 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="N/HAPMlW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9208E1F00898; Thu, 17 Sep 2026 15:56:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789660582; bh=rwwhheyN4Ngv9GM7l5UOSZDcb1zTifblnHVXmgWGiO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=N/HAPMlWwdiNG1RbLPDMCyIePRoWmLIavHnvmfWOyjHx3b80A2TE91/72jM+N05sR uvkcZZso9ZtXbTxm3r8FLzCdNob7Rb/o9H3G/+GiakK7meCgkrEx02r0ycumc9ZcKw +EFWwLNdsDI3KSdPXRW7TcIqTD0uCcbhVXKnBMN0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Namjae Jeon , Paulo Alcantara , Ronnie Sahlberg , Shyam Prasad N , Tom Talpey , Bharath SM Subject: [PATCH 7.2 640/733] smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr() Date: Thu, 17 Sep 2026 16:15:48 +0100 Message-ID: <20260917151408.539081046@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paulo Alcantara commit da6e25842431982d5a53cf00d925b98c690f4467 upstream. cifs_posix_to_fattr() ignores the return value of posix_info_parse(). When a malformed POSIX directory entry is encountered (e.g. invalid SID lengths from an untrusted server), posix_info_parse() returns -1 without populating the 'parsed' struct. The uninitialized stack memory in parsed.owner and parsed.group is then passed to sid_to_id(), which processes the garbage bytes and passes them to request_key() to construct a SID string, potentially leaking kernel stack contents to the userspace idmap daemon. Fix this by checking the return value and skipping the SID-to-id mapping when parsing fails. The remaining fattr fields (timestamps, mode, etc.) are populated directly from the 'info' pointer so they are unaffected. Closes: https://sashiko.dev/#/patchset/20260906172005.627163-1-pc%40manguebit.org Closes: https://sashiko.dev/#/patchset/20260906181540.647469-1-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: Greg Kroah-Hartman --- fs/smb/client/readdir.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) --- a/fs/smb/client/readdir.c +++ b/fs/smb/client/readdir.c @@ -244,8 +244,9 @@ cifs_posix_to_fattr(struct cifs_fattr *f { unsigned int sbflags = cifs_sb_flags(cifs_sb); struct smb2_posix_info_parsed parsed; + int rc; - posix_info_parse(info, NULL, &parsed); + rc = posix_info_parse(info, NULL, &parsed); memset(fattr, 0, sizeof(*fattr)); fattr->cf_uniqueid = le64_to_cpu(info->Inode); @@ -284,10 +285,15 @@ cifs_posix_to_fattr(struct cifs_fattr *f 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); + if (rc < 0) { + cifs_dbg(VFS, "%s: failed to parse SIDs: %d\n", + __func__, rc); + } else { + 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)