| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20211013093118.691255c7@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date: Wed, 13 Oct 2021 09:31:18 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Xin Long <lucien.xin@...il.com>
Cc: network dev <netdev@...r.kernel.org>, davem@...emloft.net,
Dan Carpenter <dan.carpenter@...cle.com>,
Andreas Roeseler <andreas.a.roeseler@...il.com>
Subject: Re: [PATCH net] icmp: fix icmp_ext_echo_iio parsing in
icmp_build_probe
On Tue, 12 Oct 2021 04:43:07 -0400 Xin Long wrote:
> 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 <dan.carpenter@...cle.com>
> Signed-off-by: Xin Long <lucien.xin@...il.com>
> 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);
If I'm reading this right we end up with the same skb_header_pointer
call 4 times, every path ends up calling:
skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + ident_len, &_iio);
and looks like the skb does not get modified in between so these calls
are equivalent.
So why don't we instead consolidate the paths:
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 8b30cadff708..efa2ec1a85bf 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -1057,11 +1057,15 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr))
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));
@@ -1069,8 +1073,6 @@ 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));
@@ -1081,18 +1083,13 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
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);
--
2.31.1
Powered by blists - more mailing lists