[Bug 2099917] [NEW] cifs.upcall program in the cifs-utils package fails to use a valid service ticket from the credential cache if the TGT is expired or not exist

[Bharath SM]

Public bug reported:

cifs.upcall program in the cifs-utils package fails to use a valid
service ticket from the credential cache if the TGT is expired or not
exist


When mounting an SMB file share on Linux using the kernel client with Kerberos authentication, the Linux kernel's cifs.ko module makes an upcall to user space during the session setup phase to retrieve the Kerberos service ticket from the credential cache. However, the current cifs.upcall fails to retrieve the service ticket even if it is valid, but instead it makes check to TGT to see if its valid and then retrieve the service ticket, but if we already have valid service ticket we shouldn't need to check for TGT.

i.e in cases where the kernel handles upcalls for SMB session setup
requests with Kerberos authentication, if the credential cache already
contains a valid service ticket, it should be used directly without
needing to check the TGT again.


Fixed commit: https://git.samba.org/?p=cifs-utils.git;a=commit;h=af76bf2a11a060afdfd97104617a701d19d5890d

** Affects: cifs-utils (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/2099917

Title:
  cifs.upcall program in the cifs-utils package fails to use a valid
  service ticket from the credential cache if the TGT is expired or not
  exist

Status in cifs-utils package in Ubuntu:
  New

Bug description:
  cifs.upcall program in the cifs-utils package fails to use a valid
  service ticket from the credential cache if the TGT is expired or not
  exist

  
  When mounting an SMB file share on Linux using the kernel client with Kerberos authentication, the Linux kernel's cifs.ko module makes an upcall to user space during the session setup phase to retrieve the Kerberos service ticket from the credential cache. However, the current cifs.upcall fails to retrieve the service ticket even if it is valid, but instead it makes check to TGT to see if its valid and then retrieve the service ticket, but if we already have valid service ticket we shouldn't need to check for TGT.

  i.e in cases where the kernel handles upcalls for SMB session setup
  requests with Kerberos authentication, if the credential cache already
  contains a valid service ticket, it should be used directly without
  needing to check the TGT again.

  
  Fixed commit: https://git.samba.org/?p=cifs-utils.git;a=commit;h=af76bf2a11a060afdfd97104617a701d19d5890d

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