diff mbox series

[1/2] Fix write to cloned skb in ipv6_hop_ioam()

Message ID 20240219134821.14009-2-justin.iurman@uliege.be (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series ioam6: fix write to cloned skb's | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 956 this patch: 956
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 973 this patch: 973
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 973 this patch: 973
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 22 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Justin Iurman Feb. 19, 2024, 1:48 p.m. UTC 
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@redhat.com>
Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
---
 net/ipv6/exthdrs.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 4952ae792450..02e9ffb63af1 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: