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From: "René Scharfe" <l.s.r@web.de>
To: Elijah Newren <newren@gmail.com>, git@vger.kernel.org
Cc: Junio C Hamano <gitster@pobox.com>, Jeff King <peff@peff.net>
Subject: Re: [PATCH 24/30] merge-recursive: Add computation of collisions due to dir rename & merging
Date: Sun, 10 Jun 2018 12:56:31 +0200	[thread overview]
Message-ID: <7d1237c7-5a83-d766-7d93-5f0d59166067@web.de> (raw)
In-Reply-To: <20171110190550.27059-25-newren@gmail.com>

Am 10.11.2017 um 20:05 schrieb Elijah Newren:
> +static struct dir_rename_entry *check_dir_renamed(const char *path,
> +						  struct hashmap *dir_renames) {
> +	char temp[PATH_MAX];
> +	char *end;
> +	struct dir_rename_entry *entry;
> +
> +	strcpy(temp, path);
> +	while ((end = strrchr(temp, '/'))) {
> +		*end = '\0';
> +		entry = dir_rename_find_entry(dir_renames, temp);
> +		if (entry)
> +			return entry;
> +	}
> +	return NULL;
> +}

The value of PATH_MAX is platform-dependent, so it's easy to exceed when
doing cross-platform development.  It's also not a hard limit on most
operating systems, not even on Windows.  Further reading:

   https://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html

So using a fixed buffer is not a good idea, and writing to it without
checking is dangerous.  Here's a fix:

-- >8 --
Subject: [PATCH] merge-recursive: use xstrdup() instead of fixed buffer

Paths can be longer than PATH_MAX.  Avoid a buffer overrun in
check_dir_renamed() by using xstrdup() to make a private copy safely.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 merge-recursive.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index ac27abbd4c..db708176c5 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -2211,18 +2211,18 @@ static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs,
 static struct dir_rename_entry *check_dir_renamed(const char *path,
 						  struct hashmap *dir_renames)
 {
-	char temp[PATH_MAX];
+	char *temp = xstrdup(path);
 	char *end;
-	struct dir_rename_entry *entry;
+	struct dir_rename_entry *entry = NULL;;
 
-	strcpy(temp, path);
 	while ((end = strrchr(temp, '/'))) {
 		*end = '\0';
 		entry = dir_rename_find_entry(dir_renames, temp);
 		if (entry)
-			return entry;
+			break;
 	}
-	return NULL;
+	free(temp);
+	return entry;
 }
 
 static void compute_collisions(struct hashmap *collisions,
-- 
2.17.1

  reply	other threads:[~2018-06-10 10:56 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-10 19:05 [PATCH 00/30] Add directory rename detection to git Elijah Newren
2017-11-10 19:05 ` [PATCH 01/30] Tighten and correct a few testcases for merging and cherry-picking Elijah Newren
2017-11-13 19:32   ` Stefan Beller
2017-11-10 19:05 ` [PATCH 02/30] merge-recursive: Fix logic ordering issue Elijah Newren
2017-11-13 19:48   ` Stefan Beller
2017-11-13 22:04     ` Elijah Newren
2017-11-13 22:12       ` Stefan Beller
2017-11-13 23:39         ` Elijah Newren
2017-11-13 23:46           ` Stefan Beller
2017-11-10 19:05 ` [PATCH 03/30] merge-recursive: Add explanation for src_entry and dst_entry Elijah Newren
2017-11-13 21:06   ` Stefan Beller
2017-11-13 22:57     ` Elijah Newren
2017-11-13 23:11       ` Stefan Beller
2017-11-14  1:26   ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 04/30] directory rename detection: basic testcases Elijah Newren
2017-11-13 22:04   ` Stefan Beller
2017-11-14  0:57     ` Elijah Newren
2017-11-14  1:21       ` Stefan Beller
2017-11-14  1:40         ` Elijah Newren
2017-11-14  2:03     ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 05/30] directory rename detection: directory splitting testcases Elijah Newren
2017-11-13 23:20   ` Stefan Beller
2017-11-10 19:05 ` [PATCH 06/30] directory rename detection: testcases to avoid taking detection too far Elijah Newren
2017-11-13 23:25   ` Stefan Beller
2017-11-14  1:02     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 07/30] directory rename detection: partially renamed directory testcase/discussion Elijah Newren
2017-11-14  0:07   ` Stefan Beller
2017-11-10 19:05 ` [PATCH 08/30] directory rename detection: files/directories in the way of some renames Elijah Newren
2017-11-14  0:15   ` Stefan Beller
2017-11-14  1:19     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 09/30] directory rename detection: testcases checking which side did the rename Elijah Newren
2017-11-14  0:25   ` Stefan Beller
2017-11-14  1:30     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 10/30] directory rename detection: more involved edge/corner testcases Elijah Newren
2017-11-14  0:42   ` Stefan Beller
2017-11-14 21:11     ` Elijah Newren
2017-11-14 22:47       ` Stefan Beller
2017-11-10 19:05 ` [PATCH 11/30] directory rename detection: testcases exploring possibly suboptimal merges Elijah Newren
2017-11-14 20:33   ` Stefan Beller
2017-11-14 21:42     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 12/30] directory rename detection: miscellaneous testcases to complete coverage Elijah Newren
2017-11-15 20:03   ` Stefan Beller
2017-11-16 21:17     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 13/30] directory rename detection: tests for handling overwriting untracked files Elijah Newren
2017-11-10 19:05 ` [PATCH 14/30] directory rename detection: tests for handling overwriting dirty files Elijah Newren
2017-11-10 19:05 ` [PATCH 15/30] merge-recursive: Move the get_renames() function Elijah Newren
2017-11-14  4:46   ` Junio C Hamano
2017-11-14 17:41     ` Elijah Newren
2017-11-15  1:20       ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 16/30] merge-recursive: Introduce new functions to handle rename logic Elijah Newren
2017-11-14  4:56   ` Junio C Hamano
2017-11-14  5:14     ` Junio C Hamano
2017-11-14 18:24       ` Elijah Newren
2017-11-10 19:05 ` [PATCH 17/30] merge-recursive: Fix leaks of allocated renames and diff_filepairs Elijah Newren
2017-11-14  4:58   ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 18/30] merge-recursive: Make !o->detect_rename codepath more obvious Elijah Newren
2017-11-10 19:05 ` [PATCH 19/30] merge-recursive: Split out code for determining diff_filepairs Elijah Newren
2017-11-14  5:20   ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 20/30] merge-recursive: Add a new hashmap for storing directory renames Elijah Newren
2017-11-10 19:05 ` [PATCH 21/30] merge-recursive: Add get_directory_renames() Elijah Newren
2017-11-14  5:30   ` Junio C Hamano
2017-11-14 18:38     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 22/30] merge-recursive: Check for directory level conflicts Elijah Newren
2017-11-10 19:05 ` [PATCH 23/30] merge-recursive: Add a new hashmap for storing file collisions Elijah Newren
2017-11-10 19:05 ` [PATCH 24/30] merge-recursive: Add computation of collisions due to dir rename & merging Elijah Newren
2018-06-10 10:56   ` René Scharfe [this message]
2018-06-10 11:03     ` René Scharfe
2018-06-10 20:44     ` Jeff King
2018-06-11 15:03     ` Elijah Newren
2018-06-14 17:36     ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 25/30] merge-recursive: Check for file level conflicts then get new name Elijah Newren
2017-11-10 19:05 ` [PATCH 26/30] merge-recursive: When comparing files, don't include trees Elijah Newren
2017-11-10 19:05 ` [PATCH 27/30] merge-recursive: Apply necessary modifications for directory renames Elijah Newren
2017-11-15 20:23   ` Stefan Beller
2017-11-16  3:54     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 28/30] merge-recursive: Avoid clobbering untracked files with " Elijah Newren
2017-11-10 19:05 ` [RFC PATCH 29/30] merge-recursive: Fix overwriting dirty files involved in renames Elijah Newren
2017-11-10 19:05 ` [PATCH 30/30] merge-recursive: Fix remaining directory rename + dirty overwrite cases Elijah Newren
2017-11-10 22:27 ` [PATCH 00/30] Add directory rename detection to git Philip Oakley
2017-11-10 23:26   ` Elijah Newren
2017-11-13 15:04     ` Philip Oakley

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