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icmp: fix icmp_ext_echo_iio parsing in icmp_build_probe

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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: d329ea5bd8 ("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>
This commit is contained in:
Xin Long 2021-10-14 05:50:50 -04:00 committed by Jakub Kicinski
parent ea142b09a6
commit 1fcd794518
1 changed files with 11 additions and 12 deletions
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23
net/ipv4/icmp.c
View File

@ -1054,14 +1054,19 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
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 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
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);