diff mbox series

[v2,net,2/8] tcp: Fix bind() regression for v6-only wildcard and v4(-mapped-v6) non-wildcard addresses.

Message ID 20240326204251.51301-3-kuniyu@amazon.com (mailing list archive)
State Accepted
Commit d91ef1e1b55f730bee8ce286b02b7bdccbc42973
Delegated to: Netdev Maintainers
Headers show
Series tcp: Fix bind() regression and more tests. | 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: 949 this patch: 949
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: 956 this patch: 956
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: 960 this patch: 960
netdev/checkpatch warning WARNING: Non-standard signature: Diagnosed-by: WARNING: line length of 82 exceeds 80 columns WARNING: line length of 94 exceeds 80 columns
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
netdev/contest success net-next-2024-03-27--15-00 (tests: 952)

Commit Message

Kuniyuki Iwashima March 26, 2024, 8:42 p.m. UTC
Jianguo Wu reported another bind() regression introduced by bhash2.

Calling bind() for the following 3 addresses on the same port, the
3rd one should fail but now succeeds.

  1. 0.0.0.0 or ::ffff:0.0.0.0
  2. [::] w/ IPV6_V6ONLY
  3. IPv4 non-wildcard address or v4-mapped-v6 non-wildcard address

The first two bind() create tb2 like this:

  bhash2 -> tb2(:: w/ IPV6_V6ONLY) -> tb2(0.0.0.0)

The 3rd bind() will match with the IPv6 only wildcard address bucket
in inet_bind2_bucket_match_addr_any(), however, no conflicting socket
exists in the bucket.  So, inet_bhash2_conflict() will returns false,
and thus, inet_bhash2_addr_any_conflict() returns false consequently.

As a result, the 3rd bind() bypasses conflict check, which should be
done against the IPv4 wildcard address bucket.

So, in inet_bhash2_addr_any_conflict(), we must iterate over all buckets.

Note that we cannot add ipv6_only flag for inet_bind2_bucket as it
would confuse the following patetrn.

  1. [::] w/ SO_REUSE{ADDR,PORT} and IPV6_V6ONLY
  2. [::] w/ SO_REUSE{ADDR,PORT}
  3. IPv4 non-wildcard address or v4-mapped-v6 non-wildcard address

The first bind() would create a bucket with ipv6_only flag true,
the second bind() would add the [::] socket into the same bucket,
and the third bind() could succeed based on the wrong assumption
that ipv6_only bucket would not conflict with v4(-mapped-v6) address.

Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address")
Diagnosed-by: Jianguo Wu <wujianguo106@163.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv4/inet_connection_sock.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index c365fe9dbacd..167279e31a53 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -294,6 +294,7 @@  static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l
 	struct sock_reuseport *reuseport_cb;
 	struct inet_bind_hashbucket *head2;
 	struct inet_bind2_bucket *tb2;
+	bool conflict = false;
 	bool reuseport_cb_ok;
 
 	rcu_read_lock();
@@ -306,18 +307,20 @@  static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l
 
 	spin_lock(&head2->lock);
 
-	inet_bind_bucket_for_each(tb2, &head2->chain)
-		if (inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
-			break;
+	inet_bind_bucket_for_each(tb2, &head2->chain) {
+		if (!inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
+			continue;
 
-	if (tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
-					reuseport_ok)) {
-		spin_unlock(&head2->lock);
-		return true;
+		if (!inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,	reuseport_ok))
+			continue;
+
+		conflict = true;
+		break;
 	}
 
 	spin_unlock(&head2->lock);
-	return false;
+
+	return conflict;
 }
 
 /*