Prevent segfault of vhd-util scan on VHD with corrupt footer #2
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vhd-util scan can crash when ran against a VHD with a corrupt footer. Happens when the footer reports a VHD type that should have a parent (like HD_TYPE_DIFF) while having none, causing the segfault. Signed-off-by: Mathieu Labourier <[email protected]>
Nambrok
reviewed
Dec 19, 2025
| ASSERT(dst); | ||
| ASSERT(src); | ||
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| if (!*src) { |
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Since ASSERT can do nothing if compiled without debug, we could SEGFAULT on this.
Shouldn't we always check that src is not NULL?
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We discussed this with Ronan. This case should not happen (worse we found was that the parent string would be empty, a NULL ptr would have been caught earlier IIRC). We added the asserts just to be sure that things don't get worse during development.
Initially I wanted to put a check at the bottom instead of an ASSERT but that should not happen and would mean we do not trust the algorithm. I'm not against adding a proper check if you think this is better though.
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vhd-util scan can crash when ran against a VHD with a corrupt footer.
Happens when the footer reports a VHD type that should have a parent (like HD_TYPE_DIFF) while having none, causing the segfault.
This fix also escalates the error in vhd_util_scan_get_volume_parent
which was not done before.
It builds fine and is being tested on the client's pool.
This is a draft PR to get reviews before sending upstream. Do not merge.