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 1DA1253162E; Wed, 23 Sep 2026 14:34:34 +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=1790174075; cv=none; b=RnEAx1QbHkoubVw3v3wWAfzZ91FuvVkTc5dstx5ndSlIBUAPJ2/coZoKIB9sZjliHOPmV8r97h5bKJiqIA/VR93O4jGzkViYgJRECWvg3rLM//10Cc2vkw7B/4uq0pjgq/1jGkVSkRN6HYu13ePHpP0ot2gyGWoRKbxtuFOH9/g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790174075; c=relaxed/simple; bh=Bk1s0arntI39HKiZTPBitjSyEs9ub2Gfdb2arN2FJho=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=K3434gYyxzbJtQe3q1lItmPUeUDtv8fVQZ64hyeP2QcPXx6B0YPRWppyK2JAZvXqnUI4hxdD8OYADnY8dMpaq/Q3QdTeIf41fVhNFdlGK1O+Uj020WNMhf4PHQ5QlzBD+dZXpf4F2GBlUu+p85+0zDMSZzoY/oqIWDdc/aeQZ9E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fboypp/h; 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="fboypp/h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76C341F00899; Wed, 23 Sep 2026 14:34:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790174074; bh=DWj+fd4p6QV+53YCbxtMDn3Md7L7wKi6cOjERoa1lWI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fboypp/hzom9UXtDQp7jwje+AgSo7D5rn1sxqcpctptFKSaAUPmuufwXdR86DZNHa KDZa9a2j/yZnoQz4bn1/S1O8MR+SEKyKhlnOp7j18dboU143kt6V126/r2HlG3JH2x /hWjU2r7z45+BKC78WBQQOu48EjpjMryKBe1m7w8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Frank Sorenson , David Howells , Paulo Alcantara Subject: [PATCH 7.2 426/438] smb: client: fix missing lower-bound check on DFS referral string offsets Date: Wed, 23 Sep 2026 16:07:27 +0200 Message-ID: <20260923140655.962442712@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140644.756254324@linuxfoundation.org> References: <20260923140644.756254324@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: Frank Sorenson commit e83330c55edc0c3ac08aa6c95e49e4694c65523b upstream. parse_dfs_referrals() checks that DfsPathOffset and NetworkAddressOffset do not exceed the buffer end, but fails to check that they don't point inside the referral header itself. If a server provides an offset smaller than sizeof(struct dfs_referral_level_3), the derived string pointer overlaps with the struct fields, causing cifs_strndup_from_utf16() to interpret header data as UTF-16 strings. Fix this by enforcing that string offsets are at least sizeof(*ref). Fixes: 4ecce920e13a ("CIFS: move DFS response parsing out of SMB1 code") Cc: stable@vger.kernel.org Signed-off-by: Frank Sorenson Reviewed-by: David Howells Signed-off-by: Paulo Alcantara Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/misc.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/fs/smb/client/misc.c +++ b/fs/smb/client/misc.c @@ -788,7 +788,11 @@ parse_dfs_referrals(struct get_dfs_refer node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags); /* copy DfsPath */ - if (le16_to_cpu(ref->DfsPathOffset) > data_end - (char *)ref) { + if (le16_to_cpu(ref->DfsPathOffset) < sizeof(*ref) || + le16_to_cpu(ref->DfsPathOffset) > data_end - (char *)ref) { + cifs_dbg(VFS, "%s: DfsPathOffset %u out of range [%zu, %td]\n", + __func__, le16_to_cpu(ref->DfsPathOffset), + sizeof(*ref), data_end - (char *)ref); rc = -EINVAL; goto parse_DFS_referrals_exit; } @@ -802,7 +806,11 @@ parse_dfs_referrals(struct get_dfs_refer } /* copy link target UNC */ - if (le16_to_cpu(ref->NetworkAddressOffset) > data_end - (char *)ref) { + if (le16_to_cpu(ref->NetworkAddressOffset) < sizeof(*ref) || + le16_to_cpu(ref->NetworkAddressOffset) > data_end - (char *)ref) { + cifs_dbg(VFS, "%s: NetworkAddressOffset %u out of range [%zu, %td]\n", + __func__, le16_to_cpu(ref->NetworkAddressOffset), + sizeof(*ref), data_end - (char *)ref); rc = -EINVAL; goto parse_DFS_referrals_exit; }