Jeff Vander Stoep 66f8e2f03c selinux: sidtab reverse lookup hash table ... This replaces the reverse table lookup and reverse cache with a hashtable which improves cache-miss reverse-lookup times from O(n) to O(1)* and maintains the same performance as a reverse cache hit. This reduces the time needed to add a new sidtab entry from ~500us to 5us on a Pixel 3 when there are ~10,000 sidtab entries. The implementation uses the kernel's generic hashtable API, It uses the context's string represtation as the hash source, and the kernels generic string hashing algorithm full_name_hash() to reduce the string to a 32 bit value. This change also maintains the improvement introduced in commit ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve performance") which removed the need to keep the current sidtab locked during policy reload. It does however introduce periodic locking of the target sidtab while converting the hashtable. Sidtab entries are never modified or removed, so the context struct stored in the sid_to_context tree can also be used for the context_to_sid hashtable to reduce memory usage. This bug was reported by: - On the selinux bug tracker. BUG: kernel softlockup due to too many SIDs/contexts #37 https://github.com/SELinuxProject/selinux-kernel/issues/37 - Jovana Knezevic on Android's bugtracker. Bug: 140252993 "During multi-user performance testing, we create and remove users many times. selinux_android_restorecon_pkgdir goes from 1ms to over 20ms after about 200 user creations and removals. Accumulated over ~280 packages, that adds a significant time to user creation, making perf benchmarks unreliable." * Hashtable lookup is only O(1) when n < the number of buckets. Signed-off-by: Jeff Vander Stoep <jeffv@google.com> Reported-by: Stephen Smalley <sds@tycho.nsa.gov> Reported-by: Jovana Knezevic <jovanak@google.com> Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov> Tested-by: Stephen Smalley <sds@tycho.nsa.gov> [PM: subj tweak, removed changelog from patch description] Signed-off-by: Paul Moore <paul@paul-moore.com>		2019-12-09 16:14:51 -05:00
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audit.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
avc_ss.h	selinux: wrap AVC state	2018-03-20 16:58:17 -04:00
avc.h	selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link	2019-01-10 20:34:37 -05:00
classmap.h	perf_event: Add support for LSM and SELinux checks	2019-10-17 21:31:55 +02:00
conditional.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372	2019-06-05 17:37:10 +02:00
ibpkey.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295	2019-06-05 17:36:38 +02:00
initial_sid_to_string.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
netif.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
netlabel.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13	2019-05-21 11:28:45 +02:00
netnode.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295	2019-06-05 17:36:38 +02:00
netport.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295	2019-06-05 17:36:38 +02:00
objsec.h	perf_event: Add support for LSM and SELinux checks	2019-10-17 21:31:55 +02:00
security.h	selinux: sidtab reverse lookup hash table	2019-12-09 16:14:51 -05:00
xfrm.h	security: Remove rtnl_lock() in selinux_xfrm_notify_policyload()	2018-03-29 13:47:53 -04:00