[PATCH] add rule filterkey

Add support for a rule key, which can be used to tie audit records to audit
rules.  This is useful when a watched file is accessed through a link or
symlink, as well as for general audit log analysis.

Because this patch uses a string key instead of an integer key, there is a bit
of extra overhead to do the kstrdup() when a rule fires.  However, we're also
allocating memory for the audit record buffer, so it's probably not that
significant.  I went ahead with a string key because it seems more
user-friendly.

Note that the user must ensure that filterkeys are unique.  The kernel only
checks for duplicate rules.

Signed-off-by: Amy Griffis <amy.griffis@hpd.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index e051ff9c5b50..a489104ae3a4 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -122,6 +122,7 @@
 /* Rule structure sizes -- if these change, different AUDIT_ADD and
  * AUDIT_LIST commands must be implemented. */
 #define AUDIT_MAX_FIELDS   64
+#define AUDIT_MAX_KEY_LEN  32
 #define AUDIT_BITMASK_SIZE 64
 #define AUDIT_WORD(nr) ((__u32)((nr)/32))
 #define AUDIT_BIT(nr)  (1 << ((nr) - AUDIT_WORD(nr)*32))
@@ -171,6 +172,8 @@
 #define AUDIT_ARG2      (AUDIT_ARG0+2)
 #define AUDIT_ARG3      (AUDIT_ARG0+3)
 
+#define AUDIT_FILTERKEY 210
+
 #define AUDIT_NEGATE                    0x80000000
 
 /* These are the supported operators.