path: root/security/selinux/hooks.c
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authorMimi Zohar <zohar@linux.vnet.ibm.com>2014-05-12 09:28:11 -0400
committerSerge Hallyn <serge.hallyn@ubuntu.com>2014-06-03 14:21:50 -0500
commitf9b2a735bdddf836214b5dca74f6ca7712e5a08c (patch)
treec4793e07a83230143e3490dc274ad2c9883d980c /security/selinux/hooks.c
parentselinux: conditionally reschedule in hashtab_insert while loading selinux policy (diff)
ima: audit log files opened with O_DIRECT flag
Files are measured or appraised based on the IMA policy. When a file, in policy, is opened with the O_DIRECT flag, a deadlock occurs. The first attempt at resolving this lockdep temporarily removed the O_DIRECT flag and restored it, after calculating the hash. The second attempt introduced the O_DIRECT_HAVELOCK flag. Based on this flag, do_blockdev_direct_IO() would skip taking the i_mutex a second time. The third attempt, by Dmitry Kasatkin, resolves the i_mutex locking issue, by re-introducing the IMA mutex, but uncovered another problem. Reading a file with O_DIRECT flag set, writes directly to userspace pages. A second patch allocates a user-space like memory. This works for all IMA hooks, except ima_file_free(), which is called on __fput() to recalculate the file hash. Until this last issue is addressed, do not 'collect' the measurement for measuring, appraising, or auditing files opened with the O_DIRECT flag set. Based on policy, permit or deny file access. This patch defines a new IMA policy rule option named 'permit_directio'. Policy rules could be defined, based on LSM or other criteria, to permit specific applications to open files with the O_DIRECT flag set. Changelog v1: - permit or deny file access based IMA policy rules Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Acked-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Cc: <stable@vger.kernel.org>
Diffstat (limited to 'security/selinux/hooks.c')
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