| Message ID | 20241102200820.1423-1-03zouyi09.25@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | ipv6: ip6_fib: fix null-pointer dereference in ipv6_route_native_seq_show() | expand |
On Sun, 3 Nov 2024 04:08:20 +0800 Yi Zou wrote: > Check if fib6_nh is non-NULL before accessing fib6_nh->fib_nh_gw_family > in ipv6_route_native_seq_show() to prevent a null-pointer dereference. > Assign dev as dev = fib6_nh ? fib6_nh->fib_nh_dev : NULL to ensure safe > handling when nexthop_fib6_nh(rt->nh) returns NULL. Are you just sending this patch because nexthop_fib6_nh() may return NULL? Not sure it can happen since we know we're walking a v6-only table here. Please try to crash it and add a stack trace to the commit message. BTW your last posting was white space damaged. Stick to git send-email
On Sat, Nov 2, 2024 at 9:08 PM Yi Zou <03zouyi09.25@gmail.com> wrote: > > Check if fib6_nh is non-NULL before accessing fib6_nh->fib_nh_gw_family > in ipv6_route_native_seq_show() to prevent a null-pointer dereference. > Assign dev as dev = fib6_nh ? fib6_nh->fib_nh_dev : NULL to ensure safe > handling when nexthop_fib6_nh(rt->nh) returns NULL. > > Fixes: 0379e8e6a9ef ("ipv6: ip6_fib: avoid NPD in ipv6_route_native_seq_show()") I could not find this commit in upstream trees. Please make sure to sort out the details before sending a patch.
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index eb111d20615c..6632ab65d206 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -2555,14 +2555,14 @@ static int ipv6_route_native_seq_show(struct seq_file *seq, void *v) #else seq_puts(seq, "00000000000000000000000000000000 00 "); #endif - if (fib6_nh->fib_nh_gw_family) { + if (fib6_nh && fib6_nh->fib_nh_gw_family) { flags |= RTF_GATEWAY; seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6); } else { seq_puts(seq, "00000000000000000000000000000000"); } - dev = fib6_nh->fib_nh_dev; + dev = fib6_nh ? fib6_nh->fib_nh_dev : NULL; seq_printf(seq, " %08x %08x %08x %08x %8s\n", rt->fib6_metric, refcount_read(&rt->fib6_ref), 0, flags, dev ? dev->name : "");
Check if fib6_nh is non-NULL before accessing fib6_nh->fib_nh_gw_family in ipv6_route_native_seq_show() to prevent a null-pointer dereference. Assign dev as dev = fib6_nh ? fib6_nh->fib_nh_dev : NULL to ensure safe handling when nexthop_fib6_nh(rt->nh) returns NULL. Fixes: 0379e8e6a9ef ("ipv6: ip6_fib: avoid NPD in ipv6_route_native_seq_show()") Signed-off-by: Yi Zou <03zouyi09.25@gmail.com> --- net/ipv6/ip6_fib.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)