[PATCH v2 2/3] test/py: test kernel_noload decompression buffer overflow

[Simon Glass]

Hi Aristo,

On 2026-05-27T15:04:32, Aristo Chen <aristo.chen at canonical.com> wrote:
> test/py: test kernel_noload decompression buffer overflow
>
> Add sandbox tests that exercise the per-image decompression buffer that
> bootm_load_os() allocates for a compressed kernel_noload image
> (ALIGN(image_len * 4, SZ_1M)).
>
> The overflow test builds a FIT whose decompressed size far exceeds the
> per-image buffer and asserts that 'bootm loados' rejects it with a
> decompression error rather than overflowing.
>
> The boundary test builds a FIT whose decompressed size equals the
> per-image buffer exactly and asserts that 'bootm loados' succeeds,
> guarding against an off-by-one rejection at the buffer limit.
>
> Signed-off-by: Aristo Chen <aristo.chen at canonical.com>
>
> test/py/tests/test_fit.py | 126 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 126 insertions(+)

You didn't pick up my review tag so I hope you don't mind a few more nits

> diff --git a/test/py/tests/test_fit.py b/test/py/tests/test_fit.py
> @@ -426,3 +456,99 @@ class TestFitImage:
> +        ubman.run_command('bootm loados', wait_for_prompt=False)
> +        matched = ubman.p.expect(['Image too large', ubman.prompt_compiled])

Please use ubman.expect() rather than reaching into ubman.p directly

> diff --git a/test/py/tests/test_fit.py b/test/py/tests/test_fit.py
> @@ -117,6 +117,36 @@ host save hostfs 0 %(loadables1_addr)x %(loadables1_out)s %(loadables1_size)x
> +# A minimal ITS for a compressed 'kernel_noload' kernel. bootm allocates a
> +# per-image decompression buffer for this image type, sized as a multiple of
> +# the compressed length; see the test_fit_kernel_noload_decomp_* tests.
> +NOLOAD_ITS = '''

The test could use a buildconfigspec('gzip')

Regards,
Simon