Only use readable chars in Share Tokens

[nickvergessen]

Fix #5688

[mention-bot]

@nickvergessen, thanks for your PR! By analyzing the history of the files in this pull request, we identified @schiessle, @MorrisJobke and @rullzer to be potential reviewers.

[tcitworld]

Could you also patch https://github.com/nextcloud/server/blob/master/apps/dav/lib/CalDAV/CalDavBackend.php#L1928 ?

[nickvergessen]

Done, please review @tcitworld

[codecov]

Codecov Report

Merging #5734 into master will decrease coverage by 18.52%.
The diff coverage is 100%.

@@              Coverage Diff              @@
##             master    #5734       +/-   ##
=============================================
- Coverage     53.86%   35.34%   -18.53%     
+ Complexity    22756    22755        -1     
=============================================
  Files          1405     1405               
  Lines         86711    86735       +24     
  Branches       1328     1328               
=============================================
- Hits          46704    30653    -16051     
- Misses        40007    56082    +16075

Impacted Files	Coverage Δ	Complexity Δ
lib/private/Share/Share.php	67.17% <100%> (-0.03%)	514 <0> (ø)
lib/private/Share20/Manager.php	94.17% <100%> (-0.05%)	222 <0> (ø)
apps/sharebymail/lib/ShareByMailProvider.php	58.83% <100%> (-0.09%)	84 <0> (ø)
apps/files/lib/Activity/Settings/FileRestored.php	0% <0%> (-100%)	8% <0%> (ø)
...eware/Security/Exceptions/NotLoggedInException.php	0% <0%> (-100%)	1% <0%> (ø)
apps/user_ldap/lib/LDAPUtility.php	0% <0%> (-100%)	1% <0%> (ø)
lib/private/App/AppStore/Version/Version.php	0% <0%> (-100%)	3% <0%> (ø)
apps/user_ldap/lib/Migration/UUIDFixUser.php	0% <0%> (-100%)	1% <0%> (ø)
apps/dav/lib/CalDAV/Activity/Filter/Calendar.php	0% <0%> (-100%)	7% <0%> (ø)
apps/files/lib/Activity/Settings/FileCreated.php	0% <0%> (-100%)	8% <0%> (ø)
... and 516 more

[schiessle]

looks good

[rullzer]

yeah sure... fine by me... just note that this does bring down the possible combinations from 768 septillion to 54 septellion.

Or from ~89 bits of entropy down to ~85.

All still very much enough imo.

[tcitworld]

👍