[PATCH] Fix audit operators

Darrel Goeddel initiated a discussion on IRC regarding the possibility of audit_comparator() returning -EINVAL signaling an invalid operator. It is possible when creating the rule to assure that the operator is one of the 6 sane values. Here's a snip from include/linux/audit.h Note that 0 (nonsense) and 7 (all operators) are not valid values for an operator. ... #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) ... Furthermore, prior to adding these extended operators, flagging the AUDIT_NEGATE bit implied !=, and otherwise == was assumed. The following code forces the operator to be != if the AUDIT_NEGATE bit was flipped on. And if no operator was specified, == is assumed. The only invalid condition is if the AUDIT_NEGATE bit is off and all of the AUDIT_EQUAL, AUDIT_LESS_THAN, and AUDIT_GREATER_THAN bits are on--clearly a nonsensical operator. Now that this is handled at rule insertion time, the default -EINVAL return of audit_comparator() is eliminated such that the function can only return 1 or 0. If this is acceptable, let's get this applied to the current tree. :-Dustin -- diff -urpN a/kernel/auditfilter.c b/kernel/auditfilter.c --- a/kernel/auditfilter.c 2006-02-16 11:57:17.000000000 -0600 +++ b/kernel/auditfilter.c 2006-02-16 13:30:33.000000000 -0600 @@ -139,11 +139,17 @@ static struct audit_entry *audit_rule_to f->val = rule->values[i]; entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1; + + /* Support for legacy operators where + * AUDIT_NEGATE bit signifies != and otherwise assumes == */ if (f->op & AUDIT_NEGATE) - f->op |= AUDIT_NOT_EQUAL; - else if (!(f->op & AUDIT_OPERATORS)) - f->op |= AUDIT_EQUAL; - f->op &= ~AUDIT_NEGATE; + f->op = AUDIT_NOT_EQUAL; + else if (!f->op) + f->op = AUDIT_EQUAL; + else if (f->op == AUDIT_OPERATORS) { + err = -EINVAL; + goto exit_free; + } } exit_nofree: @@ -537,8 +543,6 @@ int audit_comparator(const u32 left, con return (left > right); case AUDIT_GREATER_THAN_OR_EQUAL: return (left >= right); - default: - return -EINVAL; } }