From: Jeff King <peff@peff.net>
To: "René Scharfe" <l.s.r@web.de>
Cc: Git List <git@vger.kernel.org>
Subject: Re: [PATCH] imap-send: increase command size limit
Date: Mon, 15 Apr 2024 14:55:30 -0400 [thread overview]
Message-ID: <20240415185530.GB1709228@coredump.intra.peff.net> (raw)
In-Reply-To: <7026075c-db4e-4d43-bbd1-d2edb52da9b7@web.de>
On Sun, Apr 14, 2024 at 06:47:52PM +0200, René Scharfe wrote:
> While 1KB is plenty for user names, passwords and mailbox names,
> there's no point in limiting our commands like that. Call xstrvfmt()
> instead of open-coding it and use strbuf to format the command to
> send, as we need its length. Fail hard if it exceeds INT_MAX, because
> socket_write() can't take more than that.
Hmm. I applaud your attention to detail, but this INT_MAX thing is ugly. ;)
Shouldn't socket_write() just use size_t / ssize_t?
In particular, this made me wonder what we would do for larger items.
Like, say, the actual message to be uploaded. And indeed, we use a
strbuf to read in the messages and pass the whole buffer for each to
socket_write(). So we'd possibly quietly truncate such a message.
Fixing it is a little more complicated than switching to size_t, because
the underlying SSL_write() uses an int. So we'd probably need some
looping, similar to xwrite().
In practice I doubt this is ever an issue. 2GB emails are not likely to
be usable in general. And I kind of doubt that this is a reasonable
vector for attacks, since the inputs to imap-send would generally come
from the user themselves (and certainly truncating the attack message is
probably not that interesting, though I imagine one could convince
write_in_full() to do an out-of-bounds read as a size_t becomes a
negative int which becomes a large size_t again).
So I am happy enough with this (especially given my general opinions of
imap-send in the first place).
-Peff
next prev parent reply other threads:[~2024-04-15 18:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-14 16:47 [PATCH] imap-send: increase command size limit René Scharfe
2024-04-14 17:44 ` brian m. carlson
2024-04-15 18:38 ` Junio C Hamano
2024-04-15 18:45 ` Jeff King
2024-04-16 15:31 ` René Scharfe
2024-04-15 18:55 ` Jeff King [this message]
2024-04-16 16:08 ` René Scharfe
2024-04-17 0:24 ` Jeff King
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