threads / patch / 11863

patchfix misuse of prefix_path()

Subject: [PATCH] fix misuse of prefix_path()

## tl;dr

6 messages between Feb 4, 2008 and Feb 5, 2008. Diffs are folded; open one to read it.

replies: 5people: 3as markdown or json

Junio C Hamano· Feb 4, 2008, 07:03 UTC · lore

When DEFAULT_GIT_TEMPLATE_DIR is specified as a relative path, init-db made it relative to exec_path using prefix_path(), which is wrong. prefix_path() is about a file inside the work tree. There was a similar misuse in config.c that takes relative ETC_GITCONFIG path.

A convenience function prefix_filename() can concatenate two paths to form a path that points at somewhere outside the work tree. Use it in these codepaths instead.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * This is probably an oversight in commits leading to
   7f0e39fa and I think if this patch breaks, MinGW port would
   be affected, hence I CC'ed j6t.

   There are similar misuse in builtin-mv.c that needs to be
   fixed.  But git-mv is more broken, independent from this
   prefix_path() issue.  For example, it does not check if src
   and dst are inside work tree, so (do not try this in a
   repository you care about) "git mv compat /tmp/outer-space"
   would throw tracked files in a work tree to outer space and
   then fail without touching the index.  It needs a serious
   overhaul, but because I do not use it myself, the level of
   motivation to fix it myself is very low.  A low hanging
   fruit, that is, for any git hacker wannabes...

 builtin-init-db.c |    3 +--
 config.c          |    5 +++--
 2 files changed, 4 insertions(+), 4 deletions(-)

Show changes to 2 files +4 −4

builtin-init-db.c, config.c

diff --git a/builtin-init-db.c b/builtin-init-db.c
index e1393b8..e51d447 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -142,8 +142,7 @@ static void copy_templates(const char *git_dir, int len, const char *template_di
 		template_dir = DEFAULT_GIT_TEMPLATE_DIR;
 		if (!is_absolute_path(template_dir)) {
 			const char *exec_path = git_exec_path();
-			template_dir = prefix_path(exec_path, strlen(exec_path),
-						   template_dir);
+			template_dir = prefix_filename(exec_path, strlen(exec_path), template_dir);
 		}
 	}
 	strcpy(template_path, template_dir);
diff --git a/config.c b/config.c
index 526a3f4..0b0c9bd 100644
--- a/config.c
+++ b/config.c
@@ -485,8 +485,9 @@ const char *git_etc_gitconfig(void)
 		if (!is_absolute_path(system_wide)) {
 			/* interpret path relative to exec-dir */
 			const char *exec_path = git_exec_path();
-			system_wide = prefix_path(exec_path, strlen(exec_path),
-						system_wide);
+			system_wide = strdup(prefix_filename(exec_path,
+							     strlen(exec_path),
+							     system_wide));
 		}
 	}
 	return system_wide;

-- 
1.5.4.18.gd0b8

Junio C Hamano· Feb 4, 2008, 08:09 UTC · re: Junio C Hamano · lore

[PATCH] builtin-mv: minimum fix to avoid losing files

An incorrect command "git mv subdir /outer/space" threw the subdirectory to outside of the repository and then noticed that /outer/space/subdir/ would be outside of the repository. The error checking is backwards.

This fixes the issue by being careful about use of the return value of get_pathspec(). Since the implementation already has handcrafted loop to munge each path on the command line, we use prefix_path() instead.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * This minimally fixes the issue and applies on top of the
   "setup: sanitize absolute and funny paths in get_pathspec()"
   patch I showed during the rc freeze.

   Dscho CC'ed as he owns the largest number of lines in this
   source file.

 builtin-mv.c  |    6 +++++-
 t/t7001-mv.sh |   38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletions(-)

Show changes to 2 files +43 −1

builtin-mv.c, t/t7001-mv.sh

diff --git a/builtin-mv.c b/builtin-mv.c
index 94f6dd2..68aa2a6 100644
--- a/builtin-mv.c
+++ b/builtin-mv.c
@@ -19,6 +19,7 @@ static const char **copy_pathspec(const char *prefix, const char **pathspec,
 				  int count, int base_name)
 {
 	int i;
+	int len = prefix ? strlen(prefix) : 0;
 	const char **result = xmalloc((count + 1) * sizeof(const char *));
 	memcpy(result, pathspec, count * sizeof(const char *));
 	result[count] = NULL;
@@ -32,8 +33,11 @@ static const char **copy_pathspec(const char *prefix, const char **pathspec,
 			if (last_slash)
 				result[i] = last_slash + 1;
 		}
+		result[i] = prefix_path(prefix, len, result[i]);
+		if (!result[i])
+			exit(1); /* error already given */
 	}
-	return get_pathspec(prefix, result);
+	return result;
 }
 
 static void show_list(const char *label, struct path_list *list)
diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index b1243b4..fa382c5 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -118,4 +118,42 @@ test_expect_success "Sergey Vlasov's test case" '
 	git mv ab a
 '
 
+test_expect_success 'absolute pathname' '(
+
+	rm -fr mine &&
+	mkdir mine &&
+	cd mine &&
+	test_create_repo one &&
+	cd one &&
+	mkdir sub &&
+	>sub/file &&
+	git add sub/file &&
+
+	git mv sub "$(pwd)/in" &&
+	! test -d sub &&
+	test -d in &&
+	git ls-files --error-unmatch in/file
+
+
+)'
+
+test_expect_success 'absolute pathname outside should fail' '(
+
+	rm -fr mine &&
+	mkdir mine &&
+	cd mine &&
+	out=$(pwd) &&
+	test_create_repo one &&
+	cd one &&
+	mkdir sub &&
+	>sub/file &&
+	git add sub/file &&
+
+	! git mv sub "$out/out" &&
+	test -d sub &&
+	! test -d ../in &&
+	git ls-files --error-unmatch sub/file
+
+)'
+
 test_done

-- 
1.5.4.18.gd0b8

Johannes Schindelin· Feb 4, 2008, 18:08 UTC · re: Junio C Hamano · lore

Re: [PATCH] builtin-mv: minimum fix to avoid losing files

Hi,

On Mon, 4 Feb 2008, Junio C Hamano wrote:

Show 6 quoted lines

>  * This minimally fixes the issue and applies on top of the
>    "setup: sanitize absolute and funny paths in get_pathspec()"
>    patch I showed during the rc freeze.
> 
>    Dscho CC'ed as he owns the largest number of lines in this
>    source file.

Well, "owns" is a bit too strong, wouldn't you say? "Is at fault for" maybe ;-)

Your patch looks obviously correct; I do not have time to look into other breakages of git-mv right now. Sorry.

Thanks, Dscho

Johannes Sixt· Feb 4, 2008, 11:13 UTC · re: Junio C Hamano · lore

Re: [PATCH] fix misuse of prefix_path()

Junio C Hamano <gitster@pobox.com> wrote:

Show 9 quoted lines

> When DEFAULT_GIT_TEMPLATE_DIR is specified as a relative path,
> init-db made it relative to exec_path using prefix_path(), which
> is wrong.  prefix_path() is about a file inside the work tree.
> There was a similar misuse in config.c that takes relative
> ETC_GITCONFIG path.
>
> A convenience function prefix_filename() can concatenate two paths
> to form a path that points at somewhere outside the work tree.
> Use it in these codepaths instead.

Thanks for catching that. But, no, your patch does not work. The reason is that prefix_filename() assumes that the prefix ends with a directory separator ('/'), but git_exec_path() doesn't have one.

prefix_path() has the same assumption, but at the same time it does the "../" sanitization. In the MinGW configuration both relative paths begin with "../" and prefix_path() removed one path component from the prefix, but left a trailing '/' behind. IOW, so far the code worked by accident, not by design ;)

I'll work on a fix (later today).

-- Hannes

Johannes Sixt· Feb 5, 2008, 08:17 UTC · re: Johannes Sixt · lore

[PATCH] Fix misuse of prefix_path()

From: Johannes Sixt <johannes.sixt@telecom.at>

We concatenate the paths manually. (prefix_filename() won't do because it expects a prefix with a trailing '/'.)

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
---
 builtin-init-db.c |    6 +++---
 config.c          |    6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

Show changes to 2 files +6 −6

builtin-init-db.c, config.c

diff --git a/builtin-init-db.c b/builtin-init-db.c
index e1393b8..5d7cdda 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -141,9 +141,9 @@ static void copy_templates(const char *git_dir, int len, const char *template_di
 		 */
 		template_dir = DEFAULT_GIT_TEMPLATE_DIR;
 		if (!is_absolute_path(template_dir)) {
-			const char *exec_path = git_exec_path();
-			template_dir = prefix_path(exec_path, strlen(exec_path),
-						   template_dir);
+			struct strbuf d = STRBUF_INIT;
+			strbuf_addf(&d, "%s/%s", git_exec_path(), template_dir);
+			template_dir = strbuf_detach(&d, NULL);
 		}
 	}
 	strcpy(template_path, template_dir);
diff --git a/config.c b/config.c
index 526a3f4..498259e 100644
--- a/config.c
+++ b/config.c
@@ -484,9 +484,9 @@ const char *git_etc_gitconfig(void)
 		system_wide = ETC_GITCONFIG;
 		if (!is_absolute_path(system_wide)) {
 			/* interpret path relative to exec-dir */
-			const char *exec_path = git_exec_path();
-			system_wide = prefix_path(exec_path, strlen(exec_path),
-						system_wide);
+			struct strbuf d = STRBUF_INIT;
+			strbuf_addf(&d, "%s/%s", git_exec_path(), system_wide);
+			system_wide = strbuf_detach(&d, NULL);
 		}
 	}
 	return system_wide;

-- 
1.5.4.rc5.842.ge7ba5

Junio C Hamano· Feb 5, 2008, 09:45 UTC · re: Johannes Sixt · lore

Re: [PATCH] Fix misuse of prefix_path()

Sorry, I pushed out the previous one by mistake. Will apply this as a fix-up.