md5 auth is broken in sane-backend

[James Ring]

When attempting to use saned resources that are protected by md5, the current version (1.0.27-3.2ubuntu3) fails. To reproduce:

$ sudo echo testuser:goodpass:test > /etc/sane.d/saned.users

This will tell saned to put a password on the 'test' resource.

Ensure that ~/.sane/pass contains:

testuser:goodpass:test
testuser:goodpass:net:localhost:test

This will cause sane clients to send the appropriate password.

Then:

$ scanimage -d net:localhost:test --accept-md5-only > /tmp/foo
scanimage: open of device net:localhost:test failed: Access to resource has been denied

This is not expected. sane-backend built at head does not exhibit the problem.

The issue was caused upstream by https://gitlab.com/earlephilhower/backends/commit/39ceeae616a2e1638c2760d4364adcaa210a413b and was fixed by https://gitlab.com/sane-project/backends/commit/74898c4330cc25521ddbf008aa18db75fc00af1b.

It would be nice to get a new release of sane-utils to fix this issue. Thanks!