diff mbox series

[v2] nscd: Fix netlink cache invalidation if epoll is used [BZ #29415]

Message ID 5861791.lOV4Wx5bFT@linux-e202.suse.de
State Committed
Commit 02ca25fef2785974011e9c5beecc99b900b69fd7
Headers
Series [v2] nscd: Fix netlink cache invalidation if epoll is used [BZ #29415] |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit success Build for i686

Commit Message

develop--- via Libc-alpha July 27, 2022, 9:44 a.m. UTC 
  Processes cache network interface information such as whether IPv4 or IPv6
are enabled. This is only checked again if the "netlink timestamp" provided
by nscd changed, which is triggered by netlink socket activity.

However, in the epoll handler for the netlink socket, it was missed to
assign the new timestamp to the nscd database. The handler for plain poll
did that properly, copy that over.

This bug caused that e.g. processes which started before network
configuration got unusuable addresses from getaddrinfo, like IPv6 only even
though only IPv4 is available:
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/1041

It's a bit hard to reproduce, so I verified this by checking the timestamp
on calls to __check_pf manually. Without this patch it's stuck at 1, now
it's increasing on network changes as expected.

Signed-off-by: Fabian Vogt <fvogt@suse.de>
---
 nscd/connections.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

DJ Delorie July 27, 2022, 6:22 p.m. UTC | #1 
LGTM.
Reviewed-by: DJ Delorie <dj@redhat.com>
diff mbox series

Patch

diff --git a/nscd/connections.c b/nscd/connections.c
index 61d1674eb4..531d2e83df 100644
--- a/nscd/connections.c
+++ b/nscd/connections.c
@@ -2284,7 +2284,8 @@  main_loop_epoll (int efd)
 					     sizeof (buf))) != -1)
 	      ;
 
-	    __bump_nl_timestamp ();
+	    dbs[hstdb].head->extra_data[NSCD_HST_IDX_CONF_TIMESTAMP]
+	      = __bump_nl_timestamp ();
 	  }
 # endif
 	else