From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A08A13537DF; Fri, 24 Apr 2026 13:42:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777038153; cv=none; b=EP9vEi3nVNoonSmTXXvfACEIbU7NDFIgrlYyS+9tK4jVaHmlnzGx4E1Hw8Vq29CqjTBOlf8qW9BBBIuPFAoIxKqqexO2is/oKhEoqwSQXFv8rJHGGTDfbav1Lm9CcGOrWt1sQuZfOoww6FNYLdf1Bmgw7a5qXyhOXSZGAEvKCNc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777038153; c=relaxed/simple; bh=2xnFGBNalMVhKeld9z2uTo7Q/dp8Hmk0NEbBEOZFkA0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YxkhGAqKRQZsZ3o5RKSpWs76ibnp/wQ6PEwnqGI0j+vXqqVx6sBtpjZ8APebMrF6DZWIwUvukw7WH5dHN5MPFPP1aV+1jDtKwVXKB1MuWTuy+z+XoWi7DfCpOnuVCRRWB81bvfQ45jrid0YTb73fW86zNG2CZcZ3tmSwZZSlVjs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NFOVbRDs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="NFOVbRDs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34F08C19425; Fri, 24 Apr 2026 13:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777038153; bh=2xnFGBNalMVhKeld9z2uTo7Q/dp8Hmk0NEbBEOZFkA0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NFOVbRDsD8Sseq+76u20WYj6y2uGE8AkxqkYtfd+IcMKEIiuL/bfvfRozhueQuoCp UwMqBTadRMjp5u38eUd7VKEEYeyGc7JFFlw5qmM6OHUHiBzvSKiRpz5wi1rlgV0pti v0MzSc38bRxmx/eOZLNCYZjWgrF+ZuPl+Hyy/sig= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tristan Madani , Namjae Jeon , Steve French Subject: [PATCH 6.18 44/55] ksmbd: use check_add_overflow() to prevent u16 DACL size overflow Date: Fri, 24 Apr 2026 15:31:23 +0200 Message-ID: <20260424132439.186781723@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260424132430.006424517@linuxfoundation.org> References: <20260424132430.006424517@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tristan Madani commit 299f962c0b02d048fb45d248b4da493d03f3175d upstream. set_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes in u16 variables. When a file has many POSIX ACL entries, the accumulated size can wrap past 65535, causing the pointer arithmetic (char *)pndace + *size to land within already-written ACEs. Subsequent writes then overwrite earlier entries, and pndacl->size gets a truncated value. Use check_add_overflow() at each accumulation point to detect the wrap before it corrupts the buffer, consistent with existing check_mul_overflow() usage elsewhere in smbacl.c. Cc: stable@vger.kernel.org Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Signed-off-by: Tristan Madani Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/smbacl.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -596,6 +596,7 @@ static void set_posix_acl_entries_dacl(s struct smb_sid *sid; struct smb_ace *ntace; int i, j; + u16 ace_sz; if (!fattr->cf_acls) goto posix_default_acl; @@ -640,8 +641,10 @@ static void set_posix_acl_entries_dacl(s flags = 0x03; ntace = (struct smb_ace *)((char *)pndace + *size); - *size += fill_ace_for_sid(ntace, sid, ACCESS_ALLOWED, flags, + ace_sz = fill_ace_for_sid(ntace, sid, ACCESS_ALLOWED, flags, pace->e_perm, 0777); + if (check_add_overflow(*size, ace_sz, size)) + break; (*num_aces)++; if (pace->e_tag == ACL_USER) ntace->access_req |= @@ -650,8 +653,10 @@ static void set_posix_acl_entries_dacl(s if (S_ISDIR(fattr->cf_mode) && (pace->e_tag == ACL_USER || pace->e_tag == ACL_GROUP)) { ntace = (struct smb_ace *)((char *)pndace + *size); - *size += fill_ace_for_sid(ntace, sid, ACCESS_ALLOWED, + ace_sz = fill_ace_for_sid(ntace, sid, ACCESS_ALLOWED, 0x03, pace->e_perm, 0777); + if (check_add_overflow(*size, ace_sz, size)) + break; (*num_aces)++; if (pace->e_tag == ACL_USER) ntace->access_req |= @@ -691,8 +696,10 @@ posix_default_acl: } ntace = (struct smb_ace *)((char *)pndace + *size); - *size += fill_ace_for_sid(ntace, sid, ACCESS_ALLOWED, 0x0b, + ace_sz = fill_ace_for_sid(ntace, sid, ACCESS_ALLOWED, 0x0b, pace->e_perm, 0777); + if (check_add_overflow(*size, ace_sz, size)) + break; (*num_aces)++; if (pace->e_tag == ACL_USER) ntace->access_req |= @@ -728,7 +735,8 @@ static void set_ntacl_dacl(struct mnt_id break; memcpy((char *)pndace + size, ntace, nt_ace_size); - size += nt_ace_size; + if (check_add_overflow(size, nt_ace_size, &size)) + break; aces_size -= nt_ace_size; ntace = (struct smb_ace *)((char *)ntace + nt_ace_size); num_aces++;