libubox: backport security patches

This backports some security relevant patches from libubox master. These
patches should not change the existing API and ABI so that old
applications still work like before without any recompilation.
Application can now also use more secure APIs.

The new more secure interfaces are also available, but not used.

OpenWrt master and 19.07 already have these patches by using a more
recent libubox version.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

1 files changed, 132 insertions, 0 deletions

diff --git a/package/libs/libubox/patches/0008-Replace-use-of-blobmsg_check_attr-by-blobmsg_check_a.patch b/package/libs/libubox/patches/0008-Replace-use-of-blobmsg_check_attr-by-blobmsg_check_a.patch
new file mode 100644
index 0000000000..77de70afd0
--- /dev/null
+++ b/package/libs/libubox/patches/0008-Replace-use-of-blobmsg_check_attr-by-blobmsg_check_a.patch
@@ -0,0 +1,132 @@
+From 8b6a401638317906b6d9039417c1c19ea8cfeab0 Mon Sep 17 00:00:00 2001
+From: Tobias Schramm <tobleminer@gmail.com>
+Date: Tue, 13 Nov 2018 04:16:12 +0100
+Subject: Replace use of blobmsg_check_attr by blobmsg_check_attr_len
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+blobmsg_check_attr_len adds a length limit specifying the max offset
+from attr that can be read safely.
+
+Signed-off-by: Tobias Schramm <tobleminer@gmail.com>
+[rebased and reworked, line wrapped commit message, _safe -> _len]
+Signed-off-by: Petr Štetiar <ynezz@true.cz>
+---
+ blobmsg.c | 59 +++++++++++++++++++++++++++++++++++++++++++------------
+ blobmsg.h |  2 ++
+ 2 files changed, 48 insertions(+), 13 deletions(-)
+
+--- a/blobmsg.c
++++ b/blobmsg.c
+@@ -33,37 +33,70 @@ blobmsg_namelen(const struct blobmsg_hdr
+ 
+ bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
+ {
++	return blobmsg_check_attr_len(attr, name, blob_raw_len(attr));
++}
++
++static bool blobmsg_check_name(const struct blob_attr *attr, size_t len, bool name)
++{
++	char *limit = (char *) attr + len;
+ 	const struct blobmsg_hdr *hdr;
+-	const char *data;
+-	int id, len;
+ 
+-	if (blob_len(attr) < sizeof(struct blobmsg_hdr))
++	hdr = blob_data(attr);
++	if (name && !hdr->namelen)
+ 		return false;
+ 
+-	hdr = (void *) attr->data;
+-	if (!hdr->namelen && name)
++	if ((char *) hdr->name + blobmsg_namelen(hdr) > limit)
+ 		return false;
+ 
+-	if (blobmsg_namelen(hdr) > blob_len(attr) - sizeof(struct blobmsg_hdr))
++	if (blobmsg_namelen(hdr) > (blob_len(attr) - sizeof(struct blobmsg_hdr)))
+ 		return false;
+ 
+ 	if (hdr->name[blobmsg_namelen(hdr)] != 0)
+ 		return false;
+ 
+-	id = blob_id(attr);
+-	len = blobmsg_data_len(attr);
+-	if (len > blob_raw_len(attr))
+-		return false;
++	return true;
++}
++
++static const char* blobmsg_check_data(const struct blob_attr *attr, size_t len, size_t *data_len)
++{
++	char *limit = (char *) attr + len;
++	const char *data;
++
++	*data_len = blobmsg_data_len(attr);
++	if (*data_len > blob_raw_len(attr))
++		return NULL;
+ 
+ 	data = blobmsg_data(attr);
++	if (data + *data_len > limit)
++		return NULL;
+ 
++	return data;
++}
++
++bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len)
++{
++	const char *data;
++	size_t data_len;
++	int id;
++
++	if (len < sizeof(struct blob_attr))
++		return false;
++
++	if (!blobmsg_check_name(attr, len, name))
++		return false;
++
++	id = blob_id(attr);
+ 	if (id > BLOBMSG_TYPE_LAST)
+ 		return false;
+ 
+ 	if (!blob_type[id])
+ 		return true;
+ 
+-	return blob_check_type(data, len, blob_type[id]);
++	data = blobmsg_check_data(attr, len, &data_len);
++	if (!data)
++		return false;
++
++	return blob_check_type(data, data_len, blob_type[id]);
+ }
+ 
+ int blobmsg_check_array(const struct blob_attr *attr, int type)
+@@ -114,7 +147,7 @@ int blobmsg_parse_array(const struct blo
+ 		    blob_id(attr) != policy[i].type)
+ 			continue;
+ 
+-		if (!blobmsg_check_attr(attr, false))
++		if (!blobmsg_check_attr_len(attr, false, len))
+ 			return -1;
+ 
+ 		if (tb[i])
+@@ -161,7 +194,7 @@ int blobmsg_parse(const struct blobmsg_p
+ 			if (blobmsg_namelen(hdr) != pslen[i])
+ 				continue;
+ 
+-			if (!blobmsg_check_attr(attr, true))
++			if (!blobmsg_check_attr_len(attr, true, len))
+ 				return -1;
+ 
+ 			if (tb[i])
+--- a/blobmsg.h
++++ b/blobmsg.h
+@@ -107,6 +107,8 @@ static inline int blobmsg_len(const stru
+ bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
+ bool blobmsg_check_attr_list(const struct blob_attr *attr, int type);
+ 
++bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len);
++
+ /*
+  * blobmsg_check_array: validate array/table and return size
+  *