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d91ef1e1b5
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: 28044fc1d4 ("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>
Link: https://lore.kernel.org/r/20240326204251.51301-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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