This is a note to let you know that I've just added the patch titled
Fix write to cloned skb in ipv6_hop_ioam()
to the 6.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fix-write-to-cloned-skb-in-ipv6_hop_ioam.patch
and it can be found in the queue-6.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4220e8f2c7ff498a37f95a1a8eee8af2614069ba
Author: Justin Iurman <justin.iurman@xxxxxxxxx>
Date: Mon Feb 19 14:52:54 2024 +0100
Fix write to cloned skb in ipv6_hop_ioam()
[ Upstream commit f198d933c2e4f8f89e0620fbaf1ea7eac384a0eb ]
ioam6_fill_trace_data() writes inside the skb payload without ensuring
it's writeable (e.g., not cloned). This function is called both from the
input and output path. The output path (ioam6_iptunnel) already does the
check. This commit provides a fix for the input path, inside
ipv6_hop_ioam(). It also updates ip6_parse_tlv() to refresh the network
header pointer ("nh") when returning from ipv6_hop_ioam().
Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace")
Reported-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Justin Iurman <justin.iurman@xxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 4952ae7924505..02e9ffb63af19 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -177,6 +177,8 @@ static bool ip6_parse_tlv(bool hopbyhop,
case IPV6_TLV_IOAM:
if (!ipv6_hop_ioam(skb, off))
return false;
+
+ nh = skb_network_header(skb);
break;
case IPV6_TLV_JUMBO:
if (!ipv6_hop_jumbo(skb, off))
@@ -943,6 +945,14 @@ static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
if (!skb_valid_dst(skb))
ip6_route_input(skb);
+ /* About to mangle packet header */
+ if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
+ goto drop;
+
+ /* Trace pointer may have changed */
+ trace = (struct ioam6_trace_hdr *)(skb_network_header(skb)
+ + optoff + sizeof(*hdr));
+
ioam6_fill_trace_data(skb, ns, trace, true);
break;
default:
