From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, Han Young <hanyang.tony@bytedance.com>
Subject: Re: [PATCH 0/1] quote: quote space
Date: Wed, 27 Mar 2024 05:17:42 -0400 [thread overview]
Message-ID: <20240327091742.GA847537@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqqfrwlltjn.fsf@gitster.g>
On Tue, Mar 19, 2024 at 03:56:44PM -0700, Junio C Hamano wrote:
> Unfortunately, this loop can terminate prematurely when a crafted
> directory name ended with a SP. The next pathname component after
> that SP (i.e. the beginning of the possible postimage filename) will
> be a slash, and instead of rejecting that position as the valid
> separation point between pre- and post-image filenames and keep
> looping, we stopped processing right there.
>
> The fix is simple. Instead of stopping and giving up, keep going on
> when we see such a condition.
That makes sense, but leaves me with only one question...
> @@ -1292,8 +1292,15 @@ static char *git_header_name(int p_value,
> return NULL; /* no postimage name */
> second = skip_tree_prefix(p_value, name + len + 1,
> line_len - (len + 1));
> + /*
> + * If we are at the SP at the end of a directory,
> + * skip_tree_prefix() may return NULL as that makes
> + * it appears as if we have an absolute path.
> + * Keep going to find another SP.
> + */
> if (!second)
> - return NULL;
> + continue;
> +
If we saw a NULL from skip_tree_prefix() because it really was an
absolute path, is continuing the right thing? Or put another way: will
we continue to correctly reject such an absolute path, and not
accidentally find a pair of names?
I think it may be OK because true absolute paths imply that the first
entry would start with "/", and we would already have bailed earlier in
the function. So:
diff --git /foo /bar
will already be rejected at the start of "/foo". And in broken input
like:
diff --git a/foo /bar
we must assume that the start of "/bar" is a possible name, which is
what your patch is fixing. And in broken mixed input like that, we would
fail to find a valid split point, and correctly return NULL.
I guess these happen in practice with "/dev/null" as the left-hand side.
But there we'd never need the names from this line, since we'd have a
separate "deleted file mode ..." header line.
-Peff
next prev parent reply other threads:[~2024-03-27 9:17 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-19 9:52 [PATCH 0/1] quote: quote space Han Young
2024-03-19 9:52 ` [PATCH 1/1] " Han Young
2024-03-19 9:59 ` Kristoffer Haugsbakk
2024-03-19 15:15 ` [PATCH 0/1] " Junio C Hamano
2024-03-19 22:56 ` Junio C Hamano
2024-03-26 21:41 ` Junio C Hamano
2024-03-27 9:17 ` Jeff King [this message]
2024-03-27 14:59 ` Junio C Hamano
2024-03-27 22:11 ` Junio C Hamano
2024-03-28 10:32 ` Jeff King
2024-03-28 11:40 ` Jeff King
2024-03-28 17:05 ` Eric Sunshine
2024-03-28 17:31 ` Junio C Hamano
2024-03-28 21:08 ` [PATCH v2] t4126: make sure a directory with SP at the end is usable Junio C Hamano
2024-03-29 2:18 ` Junio C Hamano
2024-03-29 5:37 ` [PATCH] t4126: fix "funny directory name" test on Windows (again) Junio C Hamano
2024-03-29 12:00 ` Jeff King
2024-03-29 17:21 ` [PATCH v2] " Junio C Hamano
2024-03-29 18:34 ` Jeff King
2024-03-29 11:27 ` [PATCH v2] t4126: make sure a directory with SP at the end is usable Jeff King
2024-03-29 17:01 ` Junio C Hamano
2024-04-27 14:47 ` Johannes Schindelin
2024-04-27 17:20 ` Junio C Hamano
2024-03-28 16:19 ` [PATCH 0/1] quote: quote space Junio C Hamano
2024-03-28 16:30 ` Jeff King
2024-03-28 16:53 ` Junio C Hamano
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