From 2dcf46b079b3e31aa70b1cfe64fd12e727683c16 Mon Sep 17 00:00:00 2001 From: Baptiste Jonglez Date: Sat, 13 Jun 2020 20:17:40 +0200 Subject: libubox: backport additional length-checking fixes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fixes: FS#3177 Cc: Felix Fietkau Cc: Rafał Miłecki Signed-off-by: Baptiste Jonglez --- package/libs/libubox/Makefile | 2 +- ...-attrs-iteration-in-the-blobmsg_check_arr.patch | 73 +++++++++++ ...blobmsg-fix-length-in-blobmsg_check_array.patch | 26 ++++ ...plify-and-fix-name-length-checks-in-blobm.patch | 47 +++++++ .../0021-blobmsg-fix-missing-length-checks.patch | 137 +++++++++++++++++++++ 5 files changed, 284 insertions(+), 1 deletion(-) create mode 100644 package/libs/libubox/patches/0018-blobmsg-fix-attrs-iteration-in-the-blobmsg_check_arr.patch create mode 100644 package/libs/libubox/patches/0019-blobmsg-fix-length-in-blobmsg_check_array.patch create mode 100644 package/libs/libubox/patches/0020-blobmsg-simplify-and-fix-name-length-checks-in-blobm.patch create mode 100644 package/libs/libubox/patches/0021-blobmsg-fix-missing-length-checks.patch diff --git a/package/libs/libubox/Makefile b/package/libs/libubox/Makefile index e3a827c1ab..e4f1a6b503 100644 --- a/package/libs/libubox/Makefile +++ b/package/libs/libubox/Makefile @@ -1,7 +1,7 @@ include $(TOPDIR)/rules.mk PKG_NAME:=libubox -PKG_RELEASE=4 +PKG_RELEASE=5 PKG_SOURCE_PROTO:=git PKG_SOURCE_URL=$(PROJECT_GIT)/project/libubox.git diff --git a/package/libs/libubox/patches/0018-blobmsg-fix-attrs-iteration-in-the-blobmsg_check_arr.patch b/package/libs/libubox/patches/0018-blobmsg-fix-attrs-iteration-in-the-blobmsg_check_arr.patch new file mode 100644 index 0000000000..994bdce4a5 --- /dev/null +++ b/package/libs/libubox/patches/0018-blobmsg-fix-attrs-iteration-in-the-blobmsg_check_arr.patch @@ -0,0 +1,73 @@ +From 5e75160f48785464f9213c6bc8c72b9372c5318b Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= +Date: Sat, 23 May 2020 13:18:51 +0200 +Subject: [PATCH] blobmsg: fix attrs iteration in the blobmsg_check_array_len() +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Starting with 75e300aeec25 ("blobmsg: fix wrong payload len passed from +blobmsg_check_array") blobmsg_check_array_len() gets *blob* length +passed as argument. It cannot be used with __blobmsg_for_each_attr() +which expects *data* length. + +Use blobmsg_for_each_attr() which calculates *data* length on its own. + +The same bug was already reported in the past and there was fix attempt +in the commit cd75136b1342 ("blobmsg: fix wrong payload len passed from +blobmsg_check_array"). That change made blobmsg_check_attr_len() calls +fail however. + +This is hopefully the correct & complete fix: +1. blobmsg_check_array_len() gets *blob* length +2. It calls blobmsg_check_attr_len() which requires *blob* length +3. It uses blobmsg_for_each_attr() which gets *data* length + +This fixes iterating over random memory treated as attrs. That was +resulting in check failing randomly for totally correct blobs. It's +critical e.g. for procd project with its instance_fill_array() failing +and procd not starting services. + +Fixes: 75e300aeec25 ("blobmsg: fix wrong payload len passed from blobmsg_check_array") +Signed-off-by: Rafał Miłecki +--- + blobmsg.c | 10 ++++++---- + 1 file changed, 6 insertions(+), 4 deletions(-) + +--- a/blobmsg.c ++++ b/blobmsg.c +@@ -123,16 +123,18 @@ int blobmsg_check_array(const struct blo + return blobmsg_check_array_len(attr, type, blob_len(attr)); + } + +-int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len) ++int blobmsg_check_array_len(const struct blob_attr *attr, int type, ++ size_t blob_len) + { + struct blob_attr *cur; ++ size_t rem; + bool name; + int size = 0; + + if (type > BLOBMSG_TYPE_LAST) + return -1; + +- if (!blobmsg_check_attr_len(attr, false, len)) ++ if (!blobmsg_check_attr_len(attr, false, blob_len)) + return -1; + + switch (blobmsg_type(attr)) { +@@ -146,11 +148,11 @@ int blobmsg_check_array_len(const struct + return -1; + } + +- __blobmsg_for_each_attr(cur, attr, len) { ++ blobmsg_for_each_attr(cur, attr, rem) { + if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type) + return -1; + +- if (!blobmsg_check_attr_len(cur, name, len)) ++ if (!blobmsg_check_attr_len(cur, name, rem)) + return -1; + + size++; diff --git a/package/libs/libubox/patches/0019-blobmsg-fix-length-in-blobmsg_check_array.patch b/package/libs/libubox/patches/0019-blobmsg-fix-length-in-blobmsg_check_array.patch new file mode 100644 index 0000000000..f6cfa79c9c --- /dev/null +++ b/package/libs/libubox/patches/0019-blobmsg-fix-length-in-blobmsg_check_array.patch @@ -0,0 +1,26 @@ +From c2fc622b771f679e8f55060ac60cfe02b9a80995 Mon Sep 17 00:00:00 2001 +From: Felix Fietkau +Date: Mon, 25 May 2020 13:44:20 +0200 +Subject: [PATCH] blobmsg: fix length in blobmsg_check_array + +blobmsg_check_array_len expects the length of the full attribute buffer, +not just the data length. +Due to other missing length checks (fixed in the next commit), this did +not show up as a test failure + +Signed-off-by: Felix Fietkau +--- + blobmsg.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/blobmsg.c ++++ b/blobmsg.c +@@ -120,7 +120,7 @@ bool blobmsg_check_attr_len(const struct + + int blobmsg_check_array(const struct blob_attr *attr, int type) + { +- return blobmsg_check_array_len(attr, type, blob_len(attr)); ++ return blobmsg_check_array_len(attr, type, blob_raw_len(attr)); + } + + int blobmsg_check_array_len(const struct blob_attr *attr, int type, diff --git a/package/libs/libubox/patches/0020-blobmsg-simplify-and-fix-name-length-checks-in-blobm.patch b/package/libs/libubox/patches/0020-blobmsg-simplify-and-fix-name-length-checks-in-blobm.patch new file mode 100644 index 0000000000..e64d18afad --- /dev/null +++ b/package/libs/libubox/patches/0020-blobmsg-simplify-and-fix-name-length-checks-in-blobm.patch @@ -0,0 +1,47 @@ +From 639c29d19717616b809d9a1e9042461ab8024370 Mon Sep 17 00:00:00 2001 +From: Felix Fietkau +Date: Mon, 25 May 2020 14:49:35 +0200 +Subject: [PATCH] blobmsg: simplify and fix name length checks in + blobmsg_check_name + +blobmsg_hdr_valid_namelen was omitted when name==false +The blob_len vs blobmsg_namelen changes were not taking into account +potential padding between name and data + +Signed-off-by: Felix Fietkau +--- + blobmsg.c | 13 ++++--------- + 1 file changed, 4 insertions(+), 9 deletions(-) + +--- a/blobmsg.c ++++ b/blobmsg.c +@@ -54,8 +54,8 @@ static bool blobmsg_hdr_valid_namelen(co + + 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; ++ uint16_t namelen; + + hdr = blobmsg_hdr_from_blob(attr, len); + if (!hdr) +@@ -64,16 +64,11 @@ static bool blobmsg_check_name(const str + if (name && !hdr->namelen) + return false; + +- if (name && !blobmsg_hdr_valid_namelen(hdr, len)) ++ namelen = blobmsg_namelen(hdr); ++ if (blob_len(attr) < (size_t)blobmsg_hdrlen(namelen)) + return false; + +- if ((char *) hdr->name + blobmsg_namelen(hdr) + 1 > limit) +- return false; +- +- if (blobmsg_namelen(hdr) > (blob_len(attr) - sizeof(struct blobmsg_hdr))) +- return false; +- +- if (hdr->name[blobmsg_namelen(hdr)] != 0) ++ if (hdr->name[namelen] != 0) + return false; + + return true; diff --git a/package/libs/libubox/patches/0021-blobmsg-fix-missing-length-checks.patch b/package/libs/libubox/patches/0021-blobmsg-fix-missing-length-checks.patch new file mode 100644 index 0000000000..1f72cc0144 --- /dev/null +++ b/package/libs/libubox/patches/0021-blobmsg-fix-missing-length-checks.patch @@ -0,0 +1,137 @@ +From 66195aee50424cbda0c2d858014e4cc58a2dc029 Mon Sep 17 00:00:00 2001 +From: Felix Fietkau +Date: Mon, 25 May 2020 12:40:04 +0200 +Subject: [PATCH] blobmsg: fix missing length checks + +blobmsg_check_attr_len was calling blobmsg_check_data for some, but not all +attribute types. These checks was missing for arrays and tables. + +Additionally, the length check in blobmsg_check_data was a bit off, since +it was comparing the blobmsg data length against the raw blob attr length. + +Fix this by checking the raw blob length against the buffer length in +blobmsg_hdr_from_blob + +Signed-off-by: Felix Fietkau +--- + blobmsg.c | 66 +++++++++++++++++-------------------------------------- + 1 file changed, 20 insertions(+), 46 deletions(-) + +--- a/blobmsg.c ++++ b/blobmsg.c +@@ -36,31 +36,18 @@ bool blobmsg_check_attr(const struct blo + return blobmsg_check_attr_len(attr, name, blob_raw_len(attr)); + } + +-static const struct blobmsg_hdr* blobmsg_hdr_from_blob(const struct blob_attr *attr, size_t len) +-{ +- if (len < sizeof(struct blob_attr) + sizeof(struct blobmsg_hdr)) +- return NULL; +- +- return blob_data(attr); +-} +- +-static bool blobmsg_hdr_valid_namelen(const struct blobmsg_hdr *hdr, size_t len) +-{ +- if (len < sizeof(struct blob_attr) + sizeof(struct blobmsg_hdr) + blobmsg_namelen(hdr) + 1) +- return false; +- +- return true; +-} +- +-static bool blobmsg_check_name(const struct blob_attr *attr, size_t len, bool name) ++static bool blobmsg_check_name(const struct blob_attr *attr, bool name) + { + const struct blobmsg_hdr *hdr; + uint16_t namelen; + +- hdr = blobmsg_hdr_from_blob(attr, len); +- if (!hdr) ++ if (!blob_is_extended(attr)) ++ return !name; ++ ++ if (blob_len(attr) < sizeof(struct blobmsg_hdr)) + return false; + ++ hdr = (const struct blobmsg_hdr *)blob_data(attr); + if (name && !hdr->namelen) + return false; + +@@ -74,29 +61,20 @@ static bool blobmsg_check_name(const str + 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 (!blobmsg_check_name(attr, len, name)) ++ if (len < sizeof(struct blob_attr)) ++ return false; ++ ++ data_len = blob_raw_len(attr); ++ if (data_len < sizeof(struct blob_attr) || data_len > len) ++ return false; ++ ++ if (!blobmsg_check_name(attr, name)) + return false; + + id = blob_id(attr); +@@ -106,9 +84,8 @@ bool blobmsg_check_attr_len(const struct + if (!blob_type[id]) + return true; + +- data = blobmsg_check_data(attr, len, &data_len); +- if (!data) +- return false; ++ data = blobmsg_data(attr); ++ data_len = blobmsg_data_len(attr); + + return blob_check_type(data, data_len, blob_type[id]); + } +@@ -212,13 +189,13 @@ int blobmsg_parse(const struct blobmsg_p + } + + __blob_for_each_attr(attr, data, len) { +- hdr = blobmsg_hdr_from_blob(attr, len); +- if (!hdr) ++ if (!blobmsg_check_attr_len(attr, false, len)) + return -1; + +- if (!blobmsg_hdr_valid_namelen(hdr, len)) +- return -1; ++ if (!blob_is_extended(attr)) ++ continue; + ++ hdr = blob_data(attr); + for (i = 0; i < policy_len; i++) { + if (!policy[i].name) + continue; +@@ -230,9 +207,6 @@ int blobmsg_parse(const struct blobmsg_p + if (blobmsg_namelen(hdr) != pslen[i]) + continue; + +- if (!blobmsg_check_attr_len(attr, true, len)) +- return -1; +- + if (tb[i]) + continue; + -- cgit v1.2.3