diff options
Diffstat (limited to 'package/libs/libubox/patches/0016-blobmsg-blobmsg_parse-and-blobmsg_parse_array-oob-re.patch')
-rw-r--r-- | package/libs/libubox/patches/0016-blobmsg-blobmsg_parse-and-blobmsg_parse_array-oob-re.patch | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/package/libs/libubox/patches/0016-blobmsg-blobmsg_parse-and-blobmsg_parse_array-oob-re.patch b/package/libs/libubox/patches/0016-blobmsg-blobmsg_parse-and-blobmsg_parse_array-oob-re.patch new file mode 100644 index 0000000000..c5d6df58e9 --- /dev/null +++ b/package/libs/libubox/patches/0016-blobmsg-blobmsg_parse-and-blobmsg_parse_array-oob-re.patch @@ -0,0 +1,110 @@ +From 6289e2d29883d5d9510b6a15c18c597478967a42 Mon Sep 17 00:00:00 2001 +From: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr> +Date: Sun, 12 Jan 2020 12:26:18 +0100 +Subject: blobmsg: blobmsg_parse and blobmsg_parse_array oob read fixes +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Fix out of bounds read in blobmsg_parse and blobmsg_check_name. The +out of bounds read happens because blob_attr and blobmsg_hdr have +flexible array members, whose size is 0 in the corresponding sizeofs. +For example the __blob_for_each_attr macro checks whether rem >= +sizeof(struct blob_attr). However, what LibFuzzer discovered was, +if the input data was only 4 bytes, the data would be casted to blob_attr, +and later on blob_data(attr) would be called even though attr->data was empty. +The same issue could appear with data larger than 4 bytes, where data +wasn't empty, but contained only the start of the blobmsg_hdr struct, +and blobmsg_hdr name was empty. The bugs were discovered by fuzzing +blobmsg_parse and blobmsg_array_parse with LibFuzzer. + +CC: Luka Perkov <luka.perkov@sartura.hr> +Reviewed-by: Jo-Philipp Wich <jo@mein.io> +Signed-off-by: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr> +[refactored some checks, added fuzz inputs, adjusted unit test results] +Signed-off-by: Petr Štetiar <ynezz@true.cz> +--- + blobmsg.c | 40 ++++++++++++++++++++++++++++++++-------- + 1 file changed, 32 insertions(+), 8 deletions(-) + +--- a/blobmsg.c ++++ b/blobmsg.c +@@ -36,16 +36,38 @@ 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) + { + char *limit = (char *) attr + len; + const struct blobmsg_hdr *hdr; + +- hdr = blob_data(attr); ++ hdr = blobmsg_hdr_from_blob(attr, len); ++ if (!hdr) ++ return false; ++ + if (name && !hdr->namelen) + return false; + +- if ((char *) hdr->name + blobmsg_namelen(hdr) > limit) ++ if (name && !blobmsg_hdr_valid_namelen(hdr, len)) ++ return false; ++ ++ if ((char *) hdr->name + blobmsg_namelen(hdr) + 1 > limit) + return false; + + if (blobmsg_namelen(hdr) > (blob_len(attr) - sizeof(struct blobmsg_hdr))) +@@ -79,9 +101,6 @@ bool blobmsg_check_attr_len(const struct + size_t data_len; + int id; + +- if (len < sizeof(struct blob_attr)) +- return false; +- + if (!blobmsg_check_name(attr, len, name)) + return false; + +@@ -176,11 +195,10 @@ int blobmsg_parse_array(const struct blo + return 0; + } + +- + int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len, + struct blob_attr **tb, void *data, unsigned int len) + { +- struct blobmsg_hdr *hdr; ++ const struct blobmsg_hdr *hdr; + struct blob_attr *attr; + uint8_t *pslen; + int i; +@@ -197,7 +215,13 @@ int blobmsg_parse(const struct blobmsg_p + } + + __blob_for_each_attr(attr, data, len) { +- hdr = blob_data(attr); ++ hdr = blobmsg_hdr_from_blob(attr, len); ++ if (!hdr) ++ return -1; ++ ++ if (!blobmsg_hdr_valid_namelen(hdr, len)) ++ return -1; ++ + for (i = 0; i < policy_len; i++) { + if (!policy[i].name) + continue; |