Author: rwatson
Date: Thu Apr 23 17:47:15 2009
New Revision: 191434
URL: http://svn.freebsd.org/changeset/base/191434
Log:
In sysctl_ifdata(), query the ifnet pointer using the index only
once, rather than querying it, validating it, and then re-querying
it without validating it. This may avoid a NULL pointer
dereference and resulting kernel page fault if an interface is
being deleted while bsnmp or other tools are querying data on the
interface.
The full fix, to properly refcount the interface for the duration
of the sysctl, is in 8.x, but is considered too high-risk for
7.2, so instead will appear in 7.3 (if all goes well).
Reproted by: mdtancsa
Approved by: re (kensmith)
Modified:
stable/7/sys/net/if_mib.c
Modified: stable/7/sys/net/if_mib.c
==============================================================================
--- stable/7/sys/net/if_mib.c Thu Apr 23 17:41:54 2009 (r191433)
+++ stable/7/sys/net/if_mib.c Thu Apr 23 17:47:15 2009 (r191434)
@@ -82,11 +82,9 @@ sysctl_ifdata(SYSCTL_HANDLER_ARGS) /* XX
return EINVAL;
if (name[0] <= 0 || name[0] > if_index ||
- ifnet_byindex(name[0]) == NULL)
+ (ifp = ifnet_byindex(name[0])) == NULL)
return ENOENT;
- ifp = ifnet_byindex(name[0]);
-
switch(name[1]) {
default:
return ENOENT;
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