kernel/linux.git/include/net/icmp.h, branch v6.19.11

ipv4: icmp: Pass IPv4 control block structure as an argument to __icmp_send()

2025-09-11T10:22:38+00:00

__icmp_send() is used to generate ICMP error messages in response to various situations such as MTU errors (i.e., "Fragmentation Required") and too many hops (i.e., "Time Exceeded"). The skb that generated the error does not necessarily come from the IPv4 layer and does not always have a valid IPv4 control block in skb->cb. Therefore, commit 9ef6b42ad6fd ("net: Add __icmp_send helper.") changed the function to take the IP options structure as argument instead of deriving it from the skb's control block. Some callers of this function such as icmp_send() pass the IP options structure from the skb's control block as in these call paths the control block is known to be valid, but other callers simply pass a zeroed structure. A subsequent patch will need __icmp_send() to access more information from the IPv4 control block (specifically, the ifindex of the input interface). As a preparation for this change, change the function to take the IPv4 control block structure as an argument instead of the IP options structure. This makes the function similar to its IPv6 counterpart that already takes the IPv6 control block structure as an argument. No functional changes intended. Reviewed-by: Petr Machata Reviewed-by: David Ahern Signed-off-by: Ido Schimmel Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250908073238.119240-3-idosch@nvidia.com Signed-off-by: Paolo Abeni

ipv6: ICMPV6: add response to ICMPV6 RFC 8335 PROBE messages

2021-06-28T21:29:45+00:00

This patch builds off of commit 2b246b2569cd2ac6ff700d0dce56b8bae29b1842 and adds functionality to respond to ICMPV6 PROBE requests. Add icmp_build_probe function to construct PROBE requests for both ICMPV4 and ICMPV6. Modify icmpv6_rcv to detect ICMPV6 PROBE messages and call the icmpv6_echo_reply handler. Modify icmpv6_echo_reply to build a PROBE response message based on the queried interface. This patch has been tested using a branch of the iputils git repo which can be found here: https://github.com/Juniper-Clinic-2020/iputils/tree/probe-request Signed-off-by: Andreas Roeseler Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

net: icmp: pass zeroed opts from icmp{,v6}_ndo_send before sending

2021-02-23T19:29:52+00:00

The icmp{,v6}_send functions make all sorts of use of skb->cb, casting it with IPCB or IP6CB, assuming the skb to have come directly from the inet layer. But when the packet comes from the ndo layer, especially when forwarded, there's no telling what might be in skb->cb at that point. As a result, the icmp sending code risks reading bogus memory contents, which can result in nasty stack overflows such as this one reported by a user: panic+0x108/0x2ea __stack_chk_fail+0x14/0x20 __icmp_send+0x5bd/0x5c0 icmp_ndo_send+0x148/0x160 In icmp_send, skb->cb is cast with IPCB and an ip_options struct is read from it. The optlen parameter there is of particular note, as it can induce writes beyond bounds. There are quite a few ways that can happen in __ip_options_echo. For example: // sptr/skb are attacker-controlled skb bytes sptr = skb_network_header(skb); // dptr/dopt points to stack memory allocated by __icmp_send dptr = dopt->__data; // sopt is the corrupt skb->cb in question if (sopt->rr) { optlen = sptr[sopt->rr+1]; // corrupt skb->cb + skb->data soffset = sptr[sopt->rr+2]; // corrupt skb->cb + skb->data // this now writes potentially attacker-controlled data, over // flowing the stack: memcpy(dptr, sptr+sopt->rr, optlen); } In the icmpv6_send case, the story is similar, but not as dire, as only IP6CB(skb)->iif and IP6CB(skb)->dsthao are used. The dsthao case is worse than the iif case, but it is passed to ipv6_find_tlv, which does a bit of bounds checking on the value. This is easy to simulate by doing a `memset(skb->cb, 0x41, sizeof(skb->cb));` before calling icmp{,v6}_ndo_send, and it's only by good fortune and the rarity of icmp sending from that context that we've avoided reports like this until now. For example, in KASAN: BUG: KASAN: stack-out-of-bounds in __ip_options_echo+0xa0e/0x12b0 Write of size 38 at addr ffff888006f1f80e by task ping/89 CPU: 2 PID: 89 Comm: ping Not tainted 5.10.0-rc7-debug+ #5 Call Trace: dump_stack+0x9a/0xcc print_address_description.constprop.0+0x1a/0x160 __kasan_report.cold+0x20/0x38 kasan_report+0x32/0x40 check_memory_region+0x145/0x1a0 memcpy+0x39/0x60 __ip_options_echo+0xa0e/0x12b0 __icmp_send+0x744/0x1700 Actually, out of the 4 drivers that do this, only gtp zeroed the cb for the v4 case, while the rest did not. So this commit actually removes the gtp-specific zeroing, while putting the code where it belongs in the shared infrastructure of icmp{,v6}_ndo_send. This commit fixes the issue by passing an empty IPCB or IP6CB along to the functions that actually do the work. For the icmp_send, this was already trivial, thanks to __icmp_send providing the plumbing function. For icmpv6_send, this required a tiny bit of refactoring to make it behave like the v4 case, after which it was straight forward. Fixes: a2b78e9b2cac ("sunvnet: generate ICMP PTMUD messages for smaller port MTUs") Reported-by: SinYu Reviewed-by: Willem de Bruijn Link: https://lore.kernel.org/netdev/CAF=yD-LOF116aHub6RMe8vB8ZpnrrnoTdqhobEx+bvoA8AsP0w@mail.gmail.com/T/ Signed-off-by: Jason A. Donenfeld Link: https://lore.kernel.org/r/20210223131858.72082-1-Jason@zx2c4.com Signed-off-by: Jakub Kicinski

icmp: introduce helper for nat'd source address in network device context

2020-02-13T22:19:00+00:00

This introduces a helper function to be called only by network drivers that wraps calls to icmp[v6]_send in a conntrack transformation, in case NAT has been used. We don't want to pollute the non-driver path, though, so we introduce this as a helper to be called by places that actually make use of this, as suggested by Florian. Signed-off-by: Jason A. Donenfeld Cc: Florian Westphal Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

net: Add __icmp_send helper.

2019-02-25T22:32:35+00:00

Add __icmp_send function having ip_options struct parameter Signed-off-by: Sergey Nazarov Reviewed-by: Paul Moore Signed-off-by: David S. Miller

net: Convert protocol error handlers from void to int

2018-11-09T01:13:08+00:00

We'll need this to handle ICMP errors for tunnels without a sending socket (i.e. FoU and GUE). There, we might have to look up different types of IP tunnels, registered as network protocols, before we get a match, so we want this for the error handlers of IPPROTO_IPIP and IPPROTO_IPV6 in both inet_protos and inet6_protos. These error codes will be used in the next patch. For consistency, return sensible error codes in protocol error handlers whenever handlers can't handle errors because, even if valid, they don't match a protocol or any of its states. This has no effect on existing error handling paths. Signed-off-by: Stefano Brivio Reviewed-by: Sabrina Dubroca Signed-off-by: David S. Miller

net: snmp: kill STATS_BH macros

2016-04-28T02:48:25+00:00

There is nothing related to BH in SNMP counters anymore, since linux-3.0. Rename helpers to use __ prefix instead of _BH prefix, for contexts where preemption is disabled. This more closely matches convention used to update percpu variables. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: icmp: rename ICMPMSGIN_INC_STATS_BH()

2016-04-28T02:48:23+00:00

Remove misleading _BH suffix. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: rename ICMP_INC_STATS_BH()

2016-04-28T02:48:22+00:00

Rename ICMP_INC_STATS_BH() to __ICMP_INC_STATS() Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller