Fix crash when PARTNAME is invalid utf-8 #136
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In GPT partitions, the PartitionName field is stored as a utf-16 string. For some reason though, in udev, the value is not converted from utf-16 to utf-8. Instead, the MSB is dropped and the LSB is kept. e.g., * letter A in UTF-16 is 0x0041. It becomes 0x41 (which is letter A) * e-ecute (é) in UTF-16 is 0x00E9. It becomes 0xE9 * euro sign (€) in UTF-16 is 0x20AC. It becomes 0xAC * pound sign (£) in UTF-16 is 0x00A3. It becomes 0xA3 In the above examples, only the letter A results in a valid UTF-8 character. When using pyudev, the values are all expected to be decodable using the system's default encoding. In probert, it can result in a crash when iterating over all the properties of a block device, that are mapped by pyudev. To work around the issue, we now stop iterating over all the values. We iterate over the keys and only access the value if we need it. Signed-off-by: Olivier Gayot <[email protected]>
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I wonder if we have this bug inside udev/systemd. I bet it treats it as binary stream, and just dumps it, which probably corrupts the output of |
@xnox I think we have the bug in udev too, yes. I've done some experiments with Dan and I also looked into the kernel and believe https://elixir.bootlin.com/linux/v6.3/source/block/partitions/efi.c#L678 is the root cause. |
In GPT partitions, the PartitionName field is stored as a utf-16 string. For some reason though, in udev, the value is not converted from utf-16 to utf-8. Instead, the MSB is dropped and the LSB is kept. e.g.,
In the above examples, only the letter A results in a valid UTF-8 character.
When using pyudev, the values are all expected to be decodable using the system's default encoding.
In probert, it can result in a crash when iterating over all the properties of a block device, that are mapped by pyudev.
To work around the issue, we now stop iterating over all the values. We iterate over the keys and only access the value if we need it.
NOTE: pyudev deprecated the use of
Device.__getitem__,Device.__iter__and similar constructs to access a pyudev.Device property. Instead, one should useDevice.properties.__getitem__,Device.properties.__iter__and so on. In a future version of pyudev, the support for the deprecated constructs will be dropped so we need to start using the recommended alternative.https://bugs.launchpad.net/subiquity/+bug/2017862