Re: [v3] net/ceph/messenger: support IPv6 Link-Local with scope identifier

On Tue, Aug 11, 2026 at 4:32 PM Alex Markuze <[email protected]> wrote:
>   1. [critical] messenger.c:1259: scope_id leaks into wire identity, breaking handshake
>      `inet_pton_with_scope()` stores the local interface index in

Uh-oh! The Ceph protocol indeed copies struct sockaddr as-is on the
wire. Is that portable?

Any way to work around this mess is ugly. I decided to fix that by
wrapping the memcmp() in a function that clears the scope id. That
requires no extra storage, and it's still possible to see the scope id
in log messages (though ceph_pr_addr() still ignores the scope id
currently).

>   2. [minor] messenger.c:1334: Allocation failure masked by DNS fallback
>      `ceph_pton()` can return `-ENOMEM` from `kstrndup()`, but
>      `ceph_parse_server_name()` treats any non-zero return as "not an IP
>      literal" and falls through to `ceph_dns_resolve_name()`. This
>      silently turns OOM into a spurious DNS lookup.
>      Suggested fix: Fall back to DNS only on `-EINVAL`; propagate
>      `-ENOMEM` directly.
>   3. [nit] messenger.c:1247: GFP_NOFS in non-filesystem context
>      `kstrndup(str, len, GFP_NOFS)` is used during mount option parsing
>      — process context, no filesystem locks held. `GFP_KERNEL` would be
>      more appropriate.

All three fixed in v4.

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Max Kellermann
Principal Architect
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