diff options
| author | Eric Dumazet <edumazet@google.com> | 2024-04-20 07:01:16 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2024-04-22 10:00:31 +0100 |
| commit | c58e88d49097bd12dfcfef4f075b43f5d5830941 (patch) | |
| tree | f0f7098b71cb530c21282731c88b63cb399b6676 | |
| parent | 0b8fe5bd73249dc20be2e88a12041f8920797b59 (diff) | |
| download | linux-c58e88d49097bd12dfcfef4f075b43f5d5830941.tar.gz | |
icmp: prevent possible NULL dereferences from icmp_build_probe()
First problem is a double call to __in_dev_get_rcu(), because
the second one could return NULL.
if (__in_dev_get_rcu(dev) && __in_dev_get_rcu(dev)->ifa_list)
Second problem is a read from dev->ip6_ptr with no NULL check:
if (!list_empty(&rcu_dereference(dev->ip6_ptr)->addr_list))
Use the correct RCU API to fix these.
v2: add missing include <net/addrconf.h>
Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Andreas Roeseler <andreas.a.roeseler@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/icmp.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index e63a3bf996176..437e782b9663b 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -92,6 +92,7 @@ #include <net/inet_common.h> #include <net/ip_fib.h> #include <net/l3mdev.h> +#include <net/addrconf.h> /* * Build xmit assembly blocks @@ -1032,6 +1033,8 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) struct icmp_ext_hdr *ext_hdr, _ext_hdr; struct icmp_ext_echo_iio *iio, _iio; struct net *net = dev_net(skb->dev); + struct inet6_dev *in6_dev; + struct in_device *in_dev; struct net_device *dev; char buff[IFNAMSIZ]; u16 ident_len; @@ -1115,10 +1118,15 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) /* Fill bits in reply message */ if (dev->flags & IFF_UP) status |= ICMP_EXT_ECHOREPLY_ACTIVE; - if (__in_dev_get_rcu(dev) && __in_dev_get_rcu(dev)->ifa_list) + + in_dev = __in_dev_get_rcu(dev); + if (in_dev && rcu_access_pointer(in_dev->ifa_list)) status |= ICMP_EXT_ECHOREPLY_IPV4; - if (!list_empty(&rcu_dereference(dev->ip6_ptr)->addr_list)) + + in6_dev = __in6_dev_get(dev); + if (in6_dev && !list_empty(&in6_dev->addr_list)) status |= ICMP_EXT_ECHOREPLY_IPV6; + dev_put(dev); icmphdr->un.echo.sequence |= htons(status); return true; |