linux/security
liqiong eb0782bbdf ima: fix deadlock when traversing "ima_default_rules".
The current IMA ruleset is identified by the variable "ima_rules"
that default to "&ima_default_rules". When loading a custom policy
for the first time, the variable is updated to "&ima_policy_rules"
instead. That update isn't RCU-safe, and deadlocks are possible.
Indeed, some functions like ima_match_policy() may loop indefinitely
when traversing "ima_default_rules" with list_for_each_entry_rcu().

When iterating over the default ruleset back to head, if the list
head is "ima_default_rules", and "ima_rules" have been updated to
"&ima_policy_rules", the loop condition (&entry->list != ima_rules)
stays always true, traversing won't terminate, causing a soft lockup
and RCU stalls.

Introduce a temporary value for "ima_rules" when iterating over
the ruleset to avoid the deadlocks.

Signed-off-by: liqiong <liqiong@nfschina.com>
Reviewed-by: THOBY Simon <Simon.THOBY@viveris.fr>
Fixes: 38d859f991 ("IMA: policy can now be updated multiple times")
Reported-by: kernel test robot <lkp@intel.com> (Fix sparse: incompatible types in comparison expression.)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09 22:17:52 -04:00
..
apparmor apparmor: use get_unaligned() only for multi-byte words 2021-05-17 13:30:29 +02:00
bpf bpf: Implement task local storage 2020-11-06 08:08:37 -08:00
integrity ima: fix deadlock when traversing "ima_default_rules". 2021-10-09 22:17:52 -04:00
keys trusted-keys: match tpm_get_ops on all return paths 2021-05-12 22:36:37 +03:00
landlock landlock: Enable user space to infer supported features 2021-04-22 12:22:11 -07:00
loadpin LSM: Add "contents" flag to kernel_read_file hook 2020-10-05 13:37:03 +02:00
lockdown Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2020-06-02 17:36:24 -07:00
safesetid LSM: SafeSetID: Mark safesetid_initialized as __initdata 2021-06-10 09:52:32 -07:00
selinux integrity-v5.15 2021-09-02 12:51:41 -07:00
smack smack: mark 'smack_enabled' global variable as __initdata 2021-07-20 10:34:59 -07:00
tomoyo mm/pagemap: add mmap_assert_locked() annotations to find_vma*() 2021-09-03 09:58:13 -07:00
yama task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
commoncap.c Miscellaneous minor fixes for v5.13. 2021-04-27 19:32:55 -07:00
device_cgroup.c device_cgroup: Fix RCU list debugging warning 2020-08-20 11:25:03 -07:00
inode.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
Kconfig landlock: Set up the security framework and manage credentials 2021-04-22 12:22:10 -07:00
Kconfig.hardening hardening: Clarify Kconfig text for auto-var-init 2021-07-20 23:02:59 -07:00
lsm_audit.c audit: remove unnecessary 'ret' initialization 2021-06-11 13:21:28 -04:00
Makefile security: remove unneeded subdir-$(CONFIG_...) 2021-09-03 08:17:20 +09:00
min_addr.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
security.c bpf: Add lockdown check for probe_write_user helper 2021-08-10 10:10:10 +02:00