Hi Dan, On 9/27/13 7:21 AM, Dan Carpenter wrote:
I have looked at this again, and I still worry that it looks like a bug. (remote security related blah blah blah). regards, dan carpenter On Mon, Feb 20, 2012 at 12:50:19PM +0300, Dan Carpenter wrote: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;
agreed.
True, but if we validate the wire data like we should, that's probably not an issue.^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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-- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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