From: Sebastian Gottschall <s.gottschall@dd-wrt.com>
To: musl@lists.openwall.com
Subject: Re: recvmsg/sendmsg broken on mips64
Date: Thu, 7 Apr 2016 13:42:17 +0200 [thread overview]
Message-ID: <a9e8f609-0172-6d7b-eced-b70bec2ee7d8@dd-wrt.com> (raw)
In-Reply-To: <20160407094806.GE9862@port70.net>
> ok so the failure is in sendmsg and in the msg_control copy.
>
> does the call fail with ENOMEM (because >1024 bytes of ancillary data)?
> that would be easy to fix..
>
> (libc has to make a copy, the struct is const and might be in
> readonly memory. a detailed bug report of the failure would
> be more useful than speculations about broken compilers..
> e.g. strace log with and without the msg_control copying.)
how to make a more detailed report than just that all netlink operations
in iproute2 fail. so the whole ip command doesnt work.
i tracked it down to recvmsg / sendmsg which do not return in success
for some reason. if i send it more detailed, which means i debug out
the real cause would also mean submit a better patch. just had no time
yet to care about since my hack works.
but does not fit to your philosophy. its easy to reproduce on any octeon
device using musl and iproute2.
>
>> #if LONG_MAX > INT_MAX
>> struct msghdr h;
>> struct cmsghdr chbuf[1024/sizeof(struct cmsghdr)+1], *c;
>> if (msg) {
>> h = *msg;
>> h.__pad1 = h.__pad2 = 0;
>> msg = &h;
>> if (h.msg_controllen) {
>> if (h.msg_controllen > 1024) {
>> errno = ENOMEM;
>> return -1;
>> }
>> memcpy(chbuf, h.msg_control, h.msg_controllen);
>> h.msg_control = chbuf;
>> for (c=CMSG_FIRSTHDR(&h); c; c=CMSG_NXTHDR(&h,c))
>> c->__pad1 = 0;
>> }
>> }
>> #endif
next prev parent reply other threads:[~2016-04-07 11:42 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 18:20 size_t and int64_t on a new platform Dan Gohman
2016-03-31 19:25 ` Rich Felker
2016-03-31 20:10 ` Szabolcs Nagy
2016-03-31 20:23 ` Alexander Monakov
2016-03-31 20:30 ` Rich Felker
2016-04-01 9:16 ` recvmsg/sendmsg broken on mips64 Sebastian Gottschall
2016-04-01 9:49 ` Szabolcs Nagy
2016-04-01 10:29 ` Sebastian Gottschall
2016-04-01 11:31 ` Szabolcs Nagy
2016-04-01 11:37 ` Sebastian Gottschall
2016-04-01 12:21 ` Masanori Ogino
2016-04-01 12:42 ` Sebastian Gottschall
2016-04-01 13:17 ` Szabolcs Nagy
2016-04-02 9:52 ` Sebastian Gottschall
2016-04-07 9:48 ` Szabolcs Nagy
2016-04-07 11:42 ` Sebastian Gottschall [this message]
2016-04-07 18:46 ` Szabolcs Nagy
2016-04-07 23:33 ` Sebastian Gottschall
2016-04-10 22:18 ` Rich Felker
2016-04-10 22:24 ` Sebastian Gottschall
2016-04-10 22:29 ` Rich Felker
2016-04-10 22:33 ` Sebastian Gottschall
2016-04-11 2:35 ` Rich Felker
2016-04-11 6:35 ` Sebastian Gottschall
2016-04-11 18:32 ` Rich Felker
2016-04-11 19:01 ` Sebastian Gottschall
2016-04-14 14:10 ` Sebastian Gottschall
2016-04-15 16:19 ` Rich Felker
2016-04-21 1:37 ` Rich Felker
2016-04-21 7:22 ` Sebastian Gottschall
2016-04-21 15:36 ` Rich Felker
2016-04-21 17:16 ` Rich Felker
2016-04-21 19:30 ` Sebastian Gottschall
2016-04-21 19:29 ` Sebastian Gottschall
2016-04-01 0:35 ` size_t and int64_t on a new platform Dan Gohman
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