I had a couple questions about some map_read_chunks().
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
150 ch_bytes = ntohl(ch->rc_target.rs_length);
^^^^^^^^
It look like this is 32 bits from the network?
151 head->arg.head[0] = rqstp->rq_arg.head[0];
152 head->arg.tail[0] = rqstp->rq_arg.tail[0];
153 head->arg.pages = &head->pages[head->count];
154 head->hdr_count = head->count; /* save count of hdr pages */
155 head->arg.page_base = 0;
156 head->arg.page_len = ch_bytes;
157 head->arg.len = rqstp->rq_arg.len + ch_bytes;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Can overflow.
158 head->arg.buflen = rqstp->rq_arg.buflen + ch_bytes;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Same. I didn't follow it through to see if an overflow matters. Does
it?
159 head->count++;
160 chl_map->ch[0].start = 0;
161 while (byte_count) {
162 rpl_map->sge[sge_no].iov_base =
163 page_address(rqstp->rq_arg.pages[page_no]) + page_off;
164 sge_bytes = min_t(int, PAGE_SIZE-page_off, ch_bytes);
^^^
This is the wrong cast to use. A large ch_bytes would be counted as a
negative value and get around the cap here.
165 rpl_map->sge[sge_no].iov_len = sge_bytes;
regards,
dan carpenter
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