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 C53E72D23A6; Sat, 12 Sep 2026 14:13:51 +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=1789222432; cv=none; b=VlkA2amx7SqefmxWA6BcWRCU2kF6lQAMW6lulHt8uFU0fszpVtb63ALTwANimHbOTgWNk3oFLN1V2Uo5air7C6cCTCpYRnGMljLOOMOFgZYKdRoz4xTG+kYqSu9E0ihZueQCzYhAl2KMq0FdykG4UH2MGu0sRPcaT8A7A+fBIU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789222432; c=relaxed/simple; bh=MuEe+xF9lqdZlyZ2sqBIvh/IY4qnMEPePyTiihUqivU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YOX6H3gMQ6OaJPRbzjb9Z8AvMoInyNfenWfLtK5x7yFpwyjchP4UhRLRHL6X2P8hCdBjLHT8xtMtJ/++FJqWFg/vZJ+H8dIrnbRQe7Z8aqfbOxEBPJOCyp6Qs7GpgV8BK3Ouq2IZfwl6/EoSu8S3uAVrmthPVM1lx2mMqP96UA0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Mz9Qg64p; 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="Mz9Qg64p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 352D81F000FF; Sat, 12 Sep 2026 14:13:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789222431; bh=RqjzXcFFfrQTtJkNP6wLkHZt/2nOgOYP/o6EudkjBcQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Mz9Qg64pgIKPCSDJXJ2L0dcuZXLqorrvNXGVb+xxASYMoGm7xs69GTVAHnh2OCYNE yC17mjlMldt2pAaFewLygCFAl3fOqP/dC/l+YREtHfOuwOEZFww5h5CFCqe65WhX8/ AixwcBJli+kH+DRGgRU9NcoZPC1iq4vjW0iqFKBU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Norbert Szetei , Namjae Jeon , Steve French , Sasha Levin Subject: [PATCH 6.6 0543/1424] ksmbd: fix overflow in dacloffset bounds check Date: Sat, 12 Sep 2026 08:49:35 +0200 Message-ID: <20260912065619.461801416@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Norbert Szetei [ Upstream commit beff0bc9d69bc8e733f9bca28e2d3df5b3e10e42 ] The dacloffset field was originally typed as int and used in an unchecked addition, which could overflow and bypass the existing bounds check in both smb_check_perm_dacl() and smb_inherit_dacl(). This could result in out-of-bounds memory access and a kernel crash when dereferencing the DACL pointer. This patch converts dacloffset to unsigned int and uses check_add_overflow() to validate access to the DACL. Cc: stable@vger.kernel.org Signed-off-by: Norbert Szetei Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/server/smbacl.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c index 06936ae521cf0..a70b6f535d86f 100644 --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -1135,7 +1135,9 @@ int smb_inherit_dacl(struct ksmbd_conn *conn, struct dentry *parent = path->dentry->d_parent; struct mnt_idmap *idmap = mnt_idmap(path->mnt); int inherited_flags = 0, flags = 0, i, nt_size = 0, pdacl_size; - int rc = 0, dacloffset, pntsd_type, pntsd_size, acl_len, aces_size; + int rc = 0, pntsd_type, pntsd_size, acl_len, aces_size; + unsigned int dacloffset; + size_t dacl_struct_end; u16 num_aces, ace_cnt = 0; char *aces_base; bool is_dir = S_ISDIR(d_inode(path->dentry)->i_mode); @@ -1144,8 +1146,11 @@ int smb_inherit_dacl(struct ksmbd_conn *conn, parent, &parent_pntsd); if (pntsd_size <= 0) return -ENOENT; + dacloffset = le32_to_cpu(parent_pntsd->dacloffset); - if (!dacloffset || (dacloffset + sizeof(struct smb_acl) > pntsd_size)) { + if (!dacloffset || + check_add_overflow(dacloffset, sizeof(struct smb_acl), &dacl_struct_end) || + dacl_struct_end > (size_t)pntsd_size) { rc = -EINVAL; goto free_parent_pntsd; } @@ -1367,7 +1372,9 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, const struct path *path, struct smb_ntsd *pntsd = NULL; struct smb_acl *pdacl; struct posix_acl *posix_acls; - int rc = 0, pntsd_size, acl_size, aces_size, pdacl_size, dacl_offset; + int rc = 0, pntsd_size, acl_size, aces_size, pdacl_size; + unsigned int dacl_offset; + size_t dacl_struct_end; struct smb_sid sid; int granted = le32_to_cpu(*pdaccess & ~FILE_MAXIMAL_ACCESS_LE); struct smb_ace *ace; @@ -1386,7 +1393,8 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, const struct path *path, dacl_offset = le32_to_cpu(pntsd->dacloffset); if (!dacl_offset || - (dacl_offset + sizeof(struct smb_acl) > pntsd_size)) + check_add_overflow(dacl_offset, sizeof(struct smb_acl), &dacl_struct_end) || + dacl_struct_end > (size_t)pntsd_size) goto err_out; pdacl = (struct smb_acl *)((char *)pntsd + le32_to_cpu(pntsd->dacloffset)); -- 2.53.0