[PATCH master] FIT: early exit if digest fails

[PATCH master] FIT: early exit if digest fails

[Ahmad Fatoum]

fit_digest will hash the list of images in the configuration, so
fit_check_signature() can compare it against the signed hash.

So far, parse errors while computing the hash were ignored. This is not
directly exploitable as the hash would be incomplete and fail the
signature verification, but it makes the code more difficult to reason
about.

This unused assignment to ret was detected by clang-analyzer-19.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 common/image-fit.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/common/image-fit.c b/common/image-fit.c
index 959384abd275..6eda041935be 100644
--- a/common/image-fit.c
+++ b/common/image-fit.c
@@ -338,6 +338,9 @@ static int fit_verify_signature(struct device_node *sig_node, const void *fit)
 
 	ret = fit_digest(fit, digest, &inc_nodes, &exc_props, hashed_strings_start,
 			 hashed_strings_size);
+	if (ret)
+		goto out_sl;
+
 	hash = xzalloc(digest_length(digest));
 	digest_final(digest, hash);
 
-- 
2.39.5

Re: [PATCH master] FIT: early exit if digest fails

[Sascha Hauer]

On Thu, 13 Mar 2025 08:23:09 +0100, Ahmad Fatoum wrote:
> fit_digest will hash the list of images in the configuration, so
> fit_check_signature() can compare it against the signed hash.
> 
> So far, parse errors while computing the hash were ignored. This is not
> directly exploitable as the hash would be incomplete and fail the
> signature verification, but it makes the code more difficult to reason
> about.
> 
> [...]

Applied, thanks!

[1/1] FIT: early exit if digest fails
      https://git.pengutronix.de/cgit/barebox/commit/?id=a676705feac6 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>