Re: [PATCH 0/3] daemon: fix network address handling bugs

From: Junio C Hamano <gitster@pobox.com>
Date: May 14, 2026, 19:20 UTC
Message-ID: <xmqqfr3tg5me.fsf@gitster.g>
In-Reply-To: <pull.2300.git.git.1778773592.gitgitgadget@gmail.com>

"Sebastien Tardif via GitGitGadget" <gitgitgadget@gmail.com> writes:

> Fix three related issues in daemon.c's network address handling:

Thanks for separating patches so that each of them addresses one specific issue.

It would have been better if you sent this series as [PATCH v2] as a reply to <pull.2299.git.git.1778291290159.gitgitgadget@gmail.com>, which is the previous round. That way, the mailing list archive will keep the related discussions together on the same page. If we visit the page for the cover letter I am responding to,

  https://lore.kernel.org/git/pull.2300.git.git.1778773592.gitgitgadget@gmail.com/

nobody can see that there was a previous iteration so those who looked at the earlier effort cannot refer back to it and compare.

Show 31 quoted lines

> IPv6 address corruption in lookup_hostname(): getaddrinfo() is called with
> AF_UNSPEC hints, so it may return IPv6 results. However, the code
> unconditionally casts ai_addr to sockaddr_in and passes AF_INET to
> inet_ntop(). On IPv6-only hosts, this reads from the wrong struct offset,
> producing garbage IP addresses. Fixed by checking ai_family and handling
> both AF_INET and AF_INET6.
>
> IPv6 address truncation in ip2str(): The sockaddr struct size (ai_addrlen)
> is passed as the output buffer size to inet_ntop(). For IPv6,
> sizeof(sockaddr_in6) is 28 bytes but INET6_ADDRSTRLEN is 46, so long IPv6
> addresses are silently truncated. Fixed by passing sizeof(ip) instead, and
> dropping the now-unused len parameter.
>
> NULL pointer in execute() logging: REMOTE_PORT environment variable is used
> in a format string without a NULL check (only REMOTE_ADDR was checked). If
> REMOTE_PORT is unset, NULL is passed to printf's %s, which is undefined
> behavior. Fixed by using a fallback string.
>
> Sebastien Tardif (3):
>   daemon: fix IPv6 address corruption in lookup_hostname()
>   daemon: fix IPv6 address truncation in ip2str()
>   daemon: guard NULL REMOTE_PORT in execute() logging
>
>  daemon.c | 31 +++++++++++++++++++++----------
>  1 file changed, 21 insertions(+), 10 deletions(-)
>
>
> base-commit: 59ff4886a579f4bc91e976fe18590b9ae02c7a08
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-2300%2FSebTardif%2Ffix%2Fdaemon-ipv6-and-null-port-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-2300/SebTardif/fix/daemon-ipv6-and-null-port-v1
> Pull-Request: https://github.com/git/git/pull/2300