From b63862f46547487388e582e8ac9083830d34f058 Mon Sep 17 00:00:00 2001 From: Dustin Kirkland Date: Thu, 3 Nov 2005 15:41:46 +0000 Subject: [PATCH] Filter rule comparators Currently, audit only supports the "=" and "!=" operators in the -F filter rules. This patch reworks the support for "=" and "!=", and adds support for ">", ">=", "<", and "<=". This turned out to be a pretty clean, and simply process. I ended up using the high order bits of the "field", as suggested by Steve and Amy. This allowed for no changes whatsoever to the netlink communications. See the documentation within the patch in the include/linux/audit.h area, where there is a table that explains the reasoning of the bitmask assignments clearly. The patch adds a new function, audit_comparator(left, op, right). This function will perform the specified comparison (op, which defaults to "==" for backward compatibility) between two values (left and right). If the negate bit is on, it will negate whatever that result was. This value is returned. Signed-off-by: Dustin Kirkland Signed-off-by: David Woodhouse --- include/linux/audit.h | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) (limited to 'include/linux/audit.h') diff --git a/include/linux/audit.h b/include/linux/audit.h index da3c01955f3d..2408cb77899c 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -98,6 +98,13 @@ #define AUDIT_WORD(nr) ((__u32)((nr)/32)) #define AUDIT_BIT(nr) (1 << ((nr) - AUDIT_WORD(nr)*32)) +/* This bitmask is used to validate user input. It represents all bits that + * are currently used in an audit field constant understood by the kernel. + * If you are adding a new #define AUDIT_, please ensure that + * AUDIT_UNUSED_BITS is updated if need be. */ +#define AUDIT_UNUSED_BITS 0x0FFFFC00 + + /* Rule fields */ /* These are useful when checking the * task structure at task creation time @@ -128,8 +135,28 @@ #define AUDIT_ARG2 (AUDIT_ARG0+2) #define AUDIT_ARG3 (AUDIT_ARG0+3) -#define AUDIT_NEGATE 0x80000000 +#define AUDIT_NEGATE 0x80000000 +/* These are the supported operators. + * 4 2 1 + * = > < + * ------- + * 0 0 0 0 nonsense + * 0 0 1 1 < + * 0 1 0 2 > + * 0 1 1 3 != + * 1 0 0 4 = + * 1 0 1 5 <= + * 1 1 0 6 >= + * 1 1 1 7 all operators + */ +#define AUDIT_LESS_THAN 0x10000000 +#define AUDIT_GREATER_THAN 0x20000000 +#define AUDIT_NOT_EQUAL 0x30000000 +#define AUDIT_EQUAL 0x40000000 +#define AUDIT_LESS_THAN_OR_EQUAL (AUDIT_LESS_THAN|AUDIT_EQUAL) +#define AUDIT_GREATER_THAN_OR_EQUAL (AUDIT_GREATER_THAN|AUDIT_EQUAL) +#define AUDIT_OPERATORS (AUDIT_EQUAL|AUDIT_NOT_EQUAL) /* Status symbols */ /* Mask values */ -- cgit v1.2.3