Re: [PATCH v2] maint: check return of split_cmdline to avoid bad config strings

From 0d52afa86d757220fefa2440c78c81bd2c8b790a Mon Sep 17 00:00:00 2001

From: Deskin Miller <redacted>
Date: Mon, 22 Sep 2008 11:06:41 -0400
Subject: [PATCH] maint: check return of split_cmdline to avoid bad config strings

As the testcase demonstrates, it's possible for split_cmdline to return -1 and
deallocate any memory it's allocated, if the config string is missing an end
quote.  In both the cases below, which are the only calling sites, the return
isn't checked, and using the pointer causes a pretty immediate segfault.

Signed-off-by: Deskin Miller <redacted>
---
On Wed, Sep 24, 2008 at 11:28:47AM +0200, Miklos Vajna wrote:

On Wed, Sep 24, 2008 at 02:10:28AM -0400, Deskin Miller [off-list ref] wrote:

quoted

As the testcase demonstrates, it's possible to have split_cmdline return -1 and
deallocate any memory it's allocated, if the config string is missing an end
quote.  In both the cases below, the return isn't checked, causing a pretty
immediate segfault.

I think this could go to the commit message.

Done in v2.

quoted

+	git merge master || test \$? = 128
+	"

Why don't you use test_must_fail here?

Didn't know about it.  Fixed in v2.

Thanks for the advice.

 builtin-merge.c        |    2 ++
 git.c                  |    2 ++
 t/t1300-repo-config.sh |   10 ++++++++++
 3 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/builtin-merge.c b/builtin-merge.c
index b280444..dcaf368 100644
--- a/builtin-merge.c
+++ b/builtin-merge.c

@@ -442,6 +442,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 
 		buf = xstrdup(v);
 		argc = split_cmdline(buf, &argv);
+		if (argc < 0)
+			die("Bad branch.%s.mergeoptions string", branch);
 		argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
 		memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
 		argc++;

diff --git a/git.c b/git.c
index fdb0f71..5582c51 100644
--- a/git.c
+++ b/git.c

@@ -162,6 +162,8 @@ static int handle_alias(int *argcp, const char ***argv)
 			    alias_string + 1, alias_command);
 		}
 		count = split_cmdline(alias_string, &new_argv);
+		if (count < 0)
+			die("Bad alias.%s string", alias_command);
 		option_count = handle_options(&new_argv, &count, &envchanged);
 		if (envchanged)
 			die("alias '%s' changes environment variables\n"

diff --git a/t/t1300-repo-config.sh b/t/t1300-repo-config.sh
index 64567fb..11b82f4 100755
--- a/t/t1300-repo-config.sh
+++ b/t/t1300-repo-config.sh

@@ -741,4 +741,14 @@ test_expect_success 'symlinked configuration' '
 
 '
 
+test_expect_success 'check split_cmdline return' "
+	git config alias.split-cmdline-fix 'echo \"' &&
+	test_must_fail git split-cmdline-fix &&
+	echo foo > foo &&
+	git add foo &&
+	git commit -m 'initial commit' &&
+	git config branch.master.mergeoptions 'echo \"' &&
+	test_must_fail git merge master
+	"
+
 test_done

-- 
1.6.0.2.GIT