programs which attach their own header) can crash the machine. The problem
in this case was:
a variable "space" was set to the total data to copy,
len was used to remember how much to copy in this chunk (mbuf),
in one case, len = min(MCLBYTES - max_hdr, resid) but
size -= MCLBYTES;
instead of
size -= len;
Note that userland programs can still crash the machine by providing
bogus data in the ip->ip_len field I suspect. I haven't verified this,
but will soon be doing so and applying a fix of some sort. Probably
clamping the ip->ip_len value to the true packet size will be ok.
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