[PATCH] test-path-utils: use xsnprintf in favor of strcpy

This strcpy will never overflow because it's copying from
baked-in test data. But we would prefer to avoid strcpy
entirely, as it makes it harder to audit for real security
bugs.

Signed-off-by: Jeff King <redacted>
---
I admit that an audit could probably just avoid looking at test-* in the
first place, but not all do (coverity complained about this one, for
example).

This sort-of applies on top of js/dirname-basename, which is in next.
Textually, it's fine, but that topic is based on v2.6.5, and xsnprintf
was only added in the v2.7.0 cycle. The simplest thing is probably to
wait for it to graduate to master, and then apply there as a new topic
(if we do v2.6.6, it's OK for it not to have this patch).

I can hold and resend in a week or two if that's easier.

 test-path-utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-path-utils.c b/test-path-utils.c
index 4ab68ac..b9ece10 100644
--- a/test-path-utils.c
+++ b/test-path-utils.c

@@ -55,7 +55,7 @@ static int test_function(struct test_data *data, char *(*func)(char *input),
 		if (!data[i].from)
 			to = func(NULL);
 		else {
-			strcpy(buffer, data[i].from);
+			xsnprintf(buffer, sizeof(buffer), "%s", data[i].from);
 			to = func(buffer);
 		}
 		if (strcmp(to, data[i].to)) {

-- 
2.7.0.244.g0701a9d

Hi Peff,

On Thu, 14 Jan 2016, Jeff King wrote:

This strcpy will never overflow because it's copying from
baked-in test data. But we would prefer to avoid strcpy
entirely, as it makes it harder to audit for real security
bugs.

Thanks.

This sort-of applies on top of js/dirname-basename, which is in next.
Textually, it's fine, but that topic is based on v2.6.5, and xsnprintf
was only added in the v2.7.0 cycle. The simplest thing is probably to
wait for it to graduate to master, and then apply there as a new topic
(if we do v2.6.6, it's OK for it not to have this patch).

I can hold and resend in a week or two if that's easier.

If you have a patch to make dirname/basename safer based on xsnprintf, I
would like to have that as soon as possible (next was rewound to 2.7.0,
no?)...

Thanks!
Dscho

On Fri, Jan 15, 2016 at 07:45:16AM +0100, Johannes Schindelin wrote:

quoted

This sort-of applies on top of js/dirname-basename, which is in next.
Textually, it's fine, but that topic is based on v2.6.5, and xsnprintf
was only added in the v2.7.0 cycle. The simplest thing is probably to
wait for it to graduate to master, and then apply there as a new topic
(if we do v2.6.6, it's OK for it not to have this patch).

I can hold and resend in a week or two if that's easier.

If you have a patch to make dirname/basename safer based on xsnprintf, I
would like to have that as soon as possible (next was rewound to 2.7.0,
no?)...

I'm not sure what you mean. `dirname/basename` themselves don't have any
problems. It's only the `strcpy` in the test program that I wanted to
fix.

If Junio wants to rebase js/dirname-basename on a more recent tip (say,
current "master") as part of the rewind, this could be applied directly
(or just squashed in).

-Peff

Hi Peff,

On Fri, 15 Jan 2016, Jeff King wrote:

On Fri, Jan 15, 2016 at 07:45:16AM +0100, Johannes Schindelin wrote:

quoted

quoted

This sort-of applies on top of js/dirname-basename, which is in next.
Textually, it's fine, but that topic is based on v2.6.5, and xsnprintf
was only added in the v2.7.0 cycle. The simplest thing is probably to
wait for it to graduate to master, and then apply there as a new topic
(if we do v2.6.6, it's OK for it not to have this patch).

I can hold and resend in a week or two if that's easier.

If you have a patch to make dirname/basename safer based on xsnprintf, I
would like to have that as soon as possible (next was rewound to 2.7.0,
no?)...

I'm not sure what you mean. `dirname/basename` themselves don't have any
problems. It's only the `strcpy` in the test program that I wanted to
fix.

If Junio wants to rebase js/dirname-basename on a more recent tip (say,
current "master") as part of the rewind, this could be applied directly
(or just squashed in).

My bad... I misunderstood which code was affected.

Sorry for the noise,
Dscho