ipv4: ARP neigh procfs buffer overflow
If arp_format_neigh_entry() can be called with n->dev->addr_len == 0, then a
write to hbuffer[-1] occurs.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index c29d75d..090e999 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -1304,7 +1304,9 @@
hbuffer[k++] = hex_asc_lo(n->ha[j]);
hbuffer[k++] = ':';
}
- hbuffer[--k] = 0;
+ if (k != 0)
+ --k;
+ hbuffer[k] = 0;
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
}
#endif