In both 2.2.x and 2.3.x, socketpair(AF_UNIX,...) fails to initialise
the peercred part of its skbuffs. That means that getsockopt with
SO_PEERCRED on such sockets reads uninitialised (and wrong) data.
Here's a patch for 2.2 and 2.3 (basically the same modulo fuzz).
It's untested but it's short enough that it "can't be wrong (TM)".
Please apply.
[This doesn't apply to 2.0 which doesn't have peercreds. It bit me
when trying to write a reliable autoconf script to check existence of
SO_PEERCRED (yes it's Linux-only at the moment but we can hope).]
-------------------- patch against 2.3.99pre6 --------------------
--- net/unix/af_unix.c.ORI Wed May 3 13:01:19 2000
+++ net/unix/af_unix.c Thu May 11 10:50:06 2000
@@ -45,6 +45,7 @@
* dgram receiver.
* Artur Skawina : Hash function optimizations
* Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
+ * Malcolm Beattie : Set peercred for socketpair
*
*
* Known differences from reference BSD that was tested:
@@ -947,6 +948,9 @@
sock_hold(skb);
unix_peer(ska)=skb;
unix_peer(skb)=ska;
+ ska->peercred.pid = skb->peercred.pid = current->pid;
+ ska->peercred.uid = skb->peercred.uid = current->euid;
+ ska->peercred.gid = skb->peercred.gid = current->egid;
if (ska->type != SOCK_DGRAM)
{
------------------ end patch against 2.3.99pre6 ------------------
---------------------- patch against 2.2.12 ----------------------
--- net/unix/af_unix.c.ORI Thu May 11 10:52:46 2000
+++ net/unix/af_unix.c Thu May 11 10:56:15 2000
@@ -43,6 +43,7 @@
* number of socks to 2*max_files and
* the number of skb queueable in the
* dgram receiver.
+ * Malcolm Beattie : Set peercred for socketpair
*
* Known differences from reference BSD that was tested:
*
@@ -814,6 +815,9 @@
unix_lock(skb);
unix_peer(ska)=skb;
unix_peer(skb)=ska;
+ ska->peercred.pid = skb->peercred.pid = current->pid;
+ ska->peercred.uid = skb->peercred.uid = current->euid;
+ ska->peercred.gid = skb->peercred.gid = current->egid;
if (ska->type != SOCK_DGRAM)
{
-------------------- end patch against 2.2.12 --------------------
--Malcolm
-- Malcolm Beattie <mbeattie@sable.ox.ac.uk> Unix Systems Programmer Oxford University Computing Services- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon May 15 2000 - 21:00:17 EST