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From: Florian Westphal <fw@strlen.de>
To: Aamir Ahmed <elb12345@hotmail.co.uk>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
	netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Subject: Re: [PATCH] netfilter: conntrack_amanda: fix port value truncation
Date: Mon, 7 Sep 2026 10:33:20 +0200	[thread overview]
Message-ID: <ap520Gf4XawDWeaX@strlen.de> (raw)
In-Reply-To: <AS8P251MB0001CCFE2A0F40637E5A366CC8B32@AS8P251MB0001.EURP251.PROD.OUTLOOK.COM>

Aamir Ahmed <elb12345@hotmail.co.uk> wrote:
> amanda_help() uses simple_strtoul() to parse the port number from
> Amanda CONNECT replies, passing the result directly through htons()
> into a __be16.  simple_strtoul() returns unsigned long, so values
> above 65535 are silently truncated by the implicit conversion to u16
> inside htons().
> 
> The existing check "port == 0 || len > 5" is insufficient: it
> catches values that truncate to zero (e.g. 65536) and strings longer
> than 5 digits, but misses values 65537-99999 whose u16 truncation is
> non-zero.  For example, port 65537 becomes port 1, creating a
> conntrack expectation for an unintended port.
> 
> Parse into an unsigned long and explicitly reject values above 65535
> before the htons() conversion, mirroring the pattern used by the FTP
> helper's get_port() and the recent IPVS FTP fix (commit
> e625a9477d12).

Is amanda still a thing?  Maybe time to retire this helper?

  parent reply	other threads:[~2026-09-07  8:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-06 23:37 Aamir Ahmed
2026-09-07  6:56 ` Chenguang Zhao
2026-09-07 16:37   ` Pablo Neira Ayuso
2026-09-08  1:37     ` Aamir Ahmed
2026-09-07  8:33 ` Florian Westphal [this message]
2026-09-09  9:39 ` netdev-bot+sashiko
2026-09-09 12:14   ` Florian Westphal
2026-09-09 23:28     ` Aamir Ahmed

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