linux/security
KP Singh aa662fc04f ima: Fix NULL pointer dereference in ima_file_hash
ima_file_hash can be called when there is no iint->ima_hash available
even though the inode exists in the integrity cache. It is fairly
common for a file to not have a hash. (e.g. an mknodat, prior to the
file being closed).

Another example where this can happen (suggested by Jann Horn):

Process A does:

	while(1) {
		unlink("/tmp/imafoo");
		fd = open("/tmp/imafoo", O_RDWR|O_CREAT|O_TRUNC, 0700);
		if (fd == -1) {
			perror("open");
			continue;
		}
		write(fd, "A", 1);
		close(fd);
	}

and Process B does:

	while (1) {
		int fd = open("/tmp/imafoo", O_RDONLY);
		if (fd == -1)
			continue;
    		char *mapping = mmap(NULL, 0x1000, PROT_READ|PROT_EXEC,
			 	     MAP_PRIVATE, fd, 0);
		if (mapping != MAP_FAILED)
			munmap(mapping, 0x1000);
		close(fd);
  	}

Due to the race to get the iint->mutex between ima_file_hash and
process_measurement iint->ima_hash could still be NULL.

Fixes: 6beea7afcc ("ima: add the ability to query the cached hash of a given file")
Signed-off-by: KP Singh <kpsingh@google.com>
Reviewed-by: Florent Revest <revest@chromium.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-16 17:43:02 -04:00
..
apparmor Minor fixes for v5.9. 2020-08-11 14:30:36 -07:00
bpf bpf: lsm: Initialize the BPF LSM hooks 2020-03-30 01:34:00 +02:00
integrity ima: Fix NULL pointer dereference in ima_file_hash 2020-09-16 17:43:02 -04:00
keys Minor fixes for v5.9. 2020-08-11 14:30:36 -07:00
loadpin block: move block-related definitions out of fs.h 2020-06-24 09:16:02 -06:00
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 security/safesetid: Replace rcu_swap_protected() with rcu_replace_pointer() 2019-10-30 08:45:57 -07:00
selinux cap-checkpoint-restore-v5.9 2020-08-04 15:02:07 -07:00
smack Smack: prevent underflow in smk_set_cipso() 2020-07-27 13:35:12 -07:00
tomoyo mm/gup: remove task_struct pointer for all gup code 2020-08-12 10:58:04 -07:00
yama sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
commoncap.c exec: Compute file based creds only once 2020-05-29 22:00:54 -05:00
device_cgroup.c device_cgroup: Cleanup cgroup eBPF device filter code 2020-04-13 14:41:54 -04:00
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 Replace HTTP links with HTTPS ones: security 2020-08-06 12:00:05 -07:00
Kconfig.hardening security: allow using Clang's zero initialization for stack variables 2020-06-16 02:06:23 -07:00
lsm_audit.c audit: purge audit_log_string from the intra-kernel audit API 2020-07-21 11:12:31 -04:00
Makefile device_cgroup: Cleanup cgroup eBPF device filter code 2020-04-13 14:41:54 -04:00
min_addr.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
security.c security: Fix hook iteration and default value for inode_copy_up_xattr 2020-06-23 16:39:23 -07:00