[PATCH] audit: AUDIT_PERM support
add support for AUDIT_PERM predicate
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/audit.h b/kernel/audit.h
index 6aa33b8..a337023 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -104,6 +104,7 @@
return (ino & (AUDIT_INODE_BUCKETS-1));
}
+extern int audit_match_class(int class, unsigned syscall);
extern int audit_comparator(const u32 left, const u32 op, const u32 right);
extern int audit_compare_dname_path(const char *dname, const char *path,
int *dirlen);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index e4cafc1..a44879b 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -302,6 +302,15 @@
return 0;
}
+int audit_match_class(int class, unsigned syscall)
+{
+ if (unlikely(syscall >= AUDIT_BITMASK_SIZE * sizeof(__u32)))
+ return 0;
+ if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
+ return 0;
+ return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
+}
+
/* Common user-space to kernel rule translation. */
static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
{
@@ -414,6 +423,10 @@
case AUDIT_ARG2:
case AUDIT_ARG3:
break;
+ case AUDIT_PERM:
+ if (f->val & ~15)
+ goto exit_free;
+ break;
case AUDIT_INODE:
err = audit_to_inode(&entry->rule, f);
if (err)
@@ -568,6 +581,10 @@
entry->rule.buflen += f->val;
entry->rule.filterkey = str;
break;
+ case AUDIT_PERM:
+ if (f->val & ~15)
+ goto exit_free;
+ break;
default:
goto exit_free;
}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index efc1b74..1bd8827 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -209,6 +209,54 @@
#endif
};
+#define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
+static inline int open_arg(int flags, int mask)
+{
+ int n = ACC_MODE(flags);
+ if (flags & (O_TRUNC | O_CREAT))
+ n |= AUDIT_PERM_WRITE;
+ return n & mask;
+}
+
+static int audit_match_perm(struct audit_context *ctx, int mask)
+{
+ unsigned n = ctx->major;
+ switch (audit_classify_syscall(ctx->arch, n)) {
+ case 0: /* native */
+ if ((mask & AUDIT_PERM_WRITE) &&
+ audit_match_class(AUDIT_CLASS_WRITE, n))
+ return 1;
+ if ((mask & AUDIT_PERM_READ) &&
+ audit_match_class(AUDIT_CLASS_READ, n))
+ return 1;
+ if ((mask & AUDIT_PERM_ATTR) &&
+ audit_match_class(AUDIT_CLASS_CHATTR, n))
+ return 1;
+ return 0;
+ case 1: /* 32bit on biarch */
+ if ((mask & AUDIT_PERM_WRITE) &&
+ audit_match_class(AUDIT_CLASS_WRITE_32, n))
+ return 1;
+ if ((mask & AUDIT_PERM_READ) &&
+ audit_match_class(AUDIT_CLASS_READ_32, n))
+ return 1;
+ if ((mask & AUDIT_PERM_ATTR) &&
+ audit_match_class(AUDIT_CLASS_CHATTR_32, n))
+ return 1;
+ return 0;
+ case 2: /* open */
+ return mask & ACC_MODE(ctx->argv[1]);
+ case 3: /* openat */
+ return mask & ACC_MODE(ctx->argv[2]);
+ case 4: /* socketcall */
+ return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
+ case 5: /* execve */
+ return mask & AUDIT_PERM_EXEC;
+ default:
+ return 0;
+ }
+}
+
/* Determine if any context name data matches a rule's watch data */
/* Compare a task_struct with an audit_rule. Return 1 on match, 0
* otherwise. */
@@ -397,6 +445,9 @@
/* ignore this field for filtering */
result = 1;
break;
+ case AUDIT_PERM:
+ result = audit_match_perm(ctx, f->val);
+ break;
}
if (!result)
