Date: Fri, 23 Dec 2011 15:08:52 -0500 From: John Baldwin <jhb@freebsd.org> To: net@freebsd.org Cc: Bjoern Zeeb <bz@freebsd.org> Subject: [PATCH] Use of unreferenced ifa in in6 Message-ID: <201112231508.52861.jhb@freebsd.org>
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The code to handle the SIOCGLIFADDR and SIOCDLIFADDR ioctls in
in6_lifaddr_ioctl() does not grab a reference to an ifnet address structure
that it uses after dropping the IF_ADDR_LOCK(). Based on other code that uses
a similar pattern of finding an ifa while under the lock and then using it
after dropping the lock, I believe it should be acquiring a reference on the
ifa and then dropping that reference when it is done using the ifa. This
(untested) patch should fix this I believe:
Index: in6.c
===================================================================
--- in6.c (revision 228777)
+++ in6.c (working copy)
@@ -1767,6 +1767,8 @@ in6_lifaddr_ioctl(struct socket *so, u_long cmd, c
if (IN6_ARE_ADDR_EQUAL(&candidate, &match))
break;
}
+ if (ifa != NULL)
+ ifa_ref(ifa);
IF_ADDR_UNLOCK(ifp);
if (!ifa)
return EADDRNOTAVAIL;
@@ -1779,16 +1781,20 @@ in6_lifaddr_ioctl(struct socket *so, u_long cmd, c
bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin6_len);
error = sa6_recoverscope(
(struct sockaddr_in6 *)&iflr->addr);
- if (error != 0)
+ if (error != 0) {
+ ifa_free(ifa);
return (error);
+ }
if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
ia->ia_dstaddr.sin6_len);
error = sa6_recoverscope(
(struct sockaddr_in6 *)&iflr->dstaddr);
- if (error != 0)
+ if (error != 0) {
+ ifa_free(ifa);
return (error);
+ }
} else
bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
@@ -1796,6 +1802,7 @@ in6_lifaddr_ioctl(struct socket *so, u_long cmd, c
in6_mask2len(&ia->ia_prefixmask.sin6_addr, NULL);
iflr->flags = ia->ia6_flags; /* XXX */
+ ifa_free(ifa);
return 0;
} else {
@@ -1819,6 +1826,7 @@ in6_lifaddr_ioctl(struct socket *so, u_long cmd, c
ia->ia_prefixmask.sin6_len);
ifra.ifra_flags = ia->ia6_flags;
+ ifa_free(ifa);
return in6_control(so, SIOCDIFADDR_IN6, (caddr_t)&ifra,
ifp, td);
}
--
John Baldwin
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