Starting with 75e300aeec ("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 cd75136b13 ("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: 75e300aeec ("blobmsg: fix wrong payload len passed from blobmsg_check_array")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
5e75160f48