diff options
author | Rafał Miłecki <rafal@milecki.pl> | 2020-05-23 13:18:51 +0200 |
---|---|---|
committer | Felix Fietkau <nbd@nbd.name> | 2020-05-24 15:22:58 +0200 |
commit | 5e75160f48785464f9213c6bc8c72b9372c5318b (patch) | |
tree | 797faae8476c0ff711bfa190e490cea594afdf4a | |
parent | eeddf22d9c280ccc4ca67dd269c6794ab8225f09 (diff) | |
download | libubox-5e75160f48785464f9213c6bc8c72b9372c5318b.tar.gz |
blobmsg: fix attrs iteration in the blobmsg_check_array_len()
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 <rafal@milecki.pl>
-rw-r--r-- | blobmsg.c | 10 |
1 files changed, 6 insertions, 4 deletions
@@ -117,16 +117,18 @@ int blobmsg_check_array(const struct blob_attr *attr, int type) 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)) { @@ -140,11 +142,11 @@ int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len) 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++; |