icmp: fix icmp_ext_echo_iio parsing in icmp_build_probe
In icmp_build_probe(), the icmp_ext_echo_iio parsing should be done
step by step and skb_header_pointer() return value should always be
checked, this patch fixes 3 places in there:
- On case ICMP_EXT_ECHO_CTYPE_NAME, it should only copy ident.name
from skb by skb_header_pointer(), its len is ident_len. Besides,
the return value of skb_header_pointer() should always be checked.
- On case ICMP_EXT_ECHO_CTYPE_INDEX, move ident_len check ahead of
skb_header_pointer(), and also do the return value check for
skb_header_pointer().
- On case ICMP_EXT_ECHO_CTYPE_ADDR, before accessing iio->ident.addr.
ctype3_hdr.addrlen, skb_header_pointer() should be called first,
then check its return value and ident_len.
On subcases ICMP_AFI_IP and ICMP_AFI_IP6, also do check for ident.
addr.ctype3_hdr.addrlen and skb_header_pointer()'s return value.
On subcase ICMP_AFI_IP, the len for skb_header_pointer() should be
"sizeof(iio->extobj_hdr) + sizeof(iio->ident.addr.ctype3_hdr) +
sizeof(struct in_addr)" or "ident_len".
v1->v2:
- To make it more clear, call skb_header_pointer() once only for
iio->indent's parsing as Jakub Suggested.
v2->v3:
- The extobj_hdr.length check against sizeof(_iio) should be done
before calling skb_header_pointer(), as Eric noticed.
Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/31628dd76657ea62f5cf78bb55da6b35240831f1.1634205050.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 8b30cad..b7e277d 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -1054,14 +1054,19 @@
iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr), &_iio);
if (!ext_hdr || !iio)
goto send_mal_query;
- if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr))
+ if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr) ||
+ ntohs(iio->extobj_hdr.length) > sizeof(_iio))
goto send_mal_query;
ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr);
+ iio = skb_header_pointer(skb, sizeof(_ext_hdr),
+ sizeof(iio->extobj_hdr) + ident_len, &_iio);
+ if (!iio)
+ goto send_mal_query;
+
status = 0;
dev = NULL;
switch (iio->extobj_hdr.class_type) {
case ICMP_EXT_ECHO_CTYPE_NAME:
- iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio);
if (ident_len >= IFNAMSIZ)
goto send_mal_query;
memset(buff, 0, sizeof(buff));
@@ -1069,30 +1074,24 @@
dev = dev_get_by_name(net, buff);
break;
case ICMP_EXT_ECHO_CTYPE_INDEX:
- iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) +
- sizeof(iio->ident.ifindex), &_iio);
if (ident_len != sizeof(iio->ident.ifindex))
goto send_mal_query;
dev = dev_get_by_index(net, ntohl(iio->ident.ifindex));
break;
case ICMP_EXT_ECHO_CTYPE_ADDR:
- if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) +
+ if (ident_len < sizeof(iio->ident.addr.ctype3_hdr) ||
+ ident_len != sizeof(iio->ident.addr.ctype3_hdr) +
iio->ident.addr.ctype3_hdr.addrlen)
goto send_mal_query;
switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) {
case ICMP_AFI_IP:
- iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) +
- sizeof(struct in_addr), &_iio);
- if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) +
- sizeof(struct in_addr))
+ if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr))
goto send_mal_query;
dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr);
break;
#if IS_ENABLED(CONFIG_IPV6)
case ICMP_AFI_IP6:
- iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio);
- if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) +
- sizeof(struct in6_addr))
+ if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr))
goto send_mal_query;
dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev);
dev_hold(dev);
