[PATCH net] icmp: fix icmp_ext_echo_iio parsing in icmp_build_probe
From: Xin Long <lucien.xin@gmail.com>
Date: 2021-10-12 08:43:13
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".
Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages")
Reported-by: Dan Carpenter <redacted>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
net/ipv4/icmp.c | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 8b30cadff708..818c79266c48 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c@@ -1061,38 +1061,48 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) 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; + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + ident_len, &_iio); + if (!iio) + goto send_mal_query; memset(buff, 0, sizeof(buff)); memcpy(buff, &iio->ident.name, ident_len); 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; + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + ident_len, &_iio); + if (!iio) + 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) + - iio->ident.addr.ctype3_hdr.addrlen) + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + sizeof(iio->ident.addr.ctype3_hdr), &_iio); + if (!iio || 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: + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) + goto send_mal_query; 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)) + ident_len, &_iio); + if (!iio) 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; + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + ident_len, &_iio); + if (!iio) goto send_mal_query; dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); dev_hold(dev);
--
2.27.0