[PATCH] [glibc] sysdeps/mach/hurd/recvmsg.c: don't try to resolve invalid address
On 08/01/2016 12:08 PM, Christian Seiler wrote:
> Problem 1 (causing SIGLOST):
>
> When msg_name and msg_namelen are filled for a SOCK_STREAM AF_LOCAL
> socket (maybe also other AF_LOCAL, didn't check) upon calling
> recvmsg, SIGLOST is generated.
So this is actually a bug in glibc, in that recvmsg (in contrast to
recvfrom) doesn't properly handle the case when __recv returns
MACH_PORT_NULL as the source port (which is the case when using
PF_LOCAL). I've attached a trivial patch that fixes this issue.
I've reported this to the glibc bugtracker:
https://sourceware.org/bugzilla/show_bug.cgi?id=20444
Regards,
Christian
Description: [hurd] recvmsg: don't try to resolve invalid address
Hurd's PF_LOCAL implementation doesn't return an address when calling
__recv. recvmsg wasn't catching that and tried to call
__socket_whatis_address on MACH_PORT_NULL, causing Hurd to send
SIGLOST to the process. Properly handle this, analogously to how
recvfrom does it.
Author: Christian Seiler <christian@iwakd.de>
Bug: https://lists.gnu.org/archive/html/bug-hurd/2016-08/msg00000.html
Last-Update: 2016-08-05
---
This patch header follows DEP-3: http://dep.debian.net/deps/dep3/
--- a/sysdeps/mach/hurd/recvmsg.c
+++ b/sysdeps/mach/hurd/recvmsg.c
@@ -202,7 +202,7 @@ __libc_recvmsg (int fd, struct msghdr *m
&message->msg_flags, amount)))
return __hurd_sockfail (fd, flags, err);
- if (message->msg_name != NULL)
+ if (message->msg_name != NULL && aport != MACH_PORT_NULL)
{
char *buf = message->msg_name;
mach_msg_type_number_t buflen = message->msg_namelen;
@@ -236,6 +236,8 @@ __libc_recvmsg (int fd, struct msghdr *m
if (buflen > 0)
((struct sockaddr *) message->msg_name)->sa_family = type;
}
+ else if (message->msg_name != NULL)
+ message->msg_namelen = 0;
__mach_port_deallocate (__mach_task_self (), aport);
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