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 5A30635E1BD for ; Wed, 23 Sep 2026 01:46:09 +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=1790127970; cv=none; b=lVQtGfmZoteXScJFK64wYG756gligMZ6lZP0UcRO8jH5ykdAILf/4i35BG2v52AO8P98peGNOaQsB5yo++KXYWfUNpm3vYpAn3Ondxj3RVroNQhgW7WyAgNcBIM0U+YrWi9CL1I0IVbMJG+Sg6b0dUQp4iF0GqhYLvjaJ3y2dC8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790127970; c=relaxed/simple; bh=c9WTH2fAx4O26my8A0H3dUrE/uN/VcmZtjFma6CQvh4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LxafvcOLjF0jH9Eh+HshJMX+ex219iRJBqT3G2rHP1CMZHmvJ7wkUmfEq2TOzrpFZnyp6TyEhIBccr8aF6nvZb6+0m2OrCYarCyNiGv9MTxJqXt78ub/vNTkzH8sM/n8F1qD8n3Dl2sPAC+Cz3CraNIOJ4Cv2K4IgTD+k3Z4gTo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=naKkHeRd; 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="naKkHeRd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80E5E1F00893; Wed, 23 Sep 2026 01:46:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790127969; bh=gMiy2SkcrbONAYOAdWjBa/jr2TBMWR0vrrDfu0fBq68=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=naKkHeRdiW+AOCWclaGDwB+1m6P7+WETiNo8PX7VuyAl+ipJBSq1nf31QsvbT1SxQ Up2tls8jwgQGRGzUPz4+VRWBrqhM+Bg3P74oqyoOD8nTdv/0R5Hvs9TlaLfsUEgVKz 4//bXhBJK6cQiyfugvZFwYKswM0TIHufRG5NUHObfsVG6dar95fm5DFMumDzo0fgDz jA7/HmKOucerh2q1+B3jHgHsWc4DPVMVKUju3Yhl3UrRCTTUwl+CdfO6e9/f6Ee84A B7ZsKqcq82x/6FWSfjW0HjBdoGgwJhbBPUUVFdBF741zzhxeYsS8ieOzGp5okxGA3G dlRP4tCu4QZqg== From: Sasha Levin To: stable@vger.kernel.org Cc: Frank Sorenson , David Howells , Paulo Alcantara , Sasha Levin Subject: [PATCH 5.10.y 2/2] smb: client: fix missing lower-bound check on DFS referral string offsets Date: Tue, 22 Sep 2026 21:46:06 -0400 Message-ID: <20260923014606.886810-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260923014606.886810-1-sashal@kernel.org> References: <2026092230-mobilize-android-8f08@gregkh> <20260923014606.886810-1-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: Frank Sorenson [ Upstream commit e83330c55edc0c3ac08aa6c95e49e4694c65523b ] 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 [ Redirected the patch from fs/smb/client/misc.c to fs/cifs/misc.c. ] Signed-off-by: Sasha Levin --- fs/cifs/misc.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 32b04a461f13b..0d4751a568e1e 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -757,7 +757,11 @@ parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size, 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; } @@ -771,7 +775,11 @@ parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size, } /* 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; } -- 2.53.0