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authorRichard Guy Briggs <rgb@redhat.com>2017-08-23 07:03:39 -0400
committerPaul Moore <paul@paul-moore.com>2017-11-10 16:08:56 -0500
commit42d5e37654e4cdb9fb2e2f3ab30045fee35c42d8 (patch)
tree5fa06c6189f135561616208016519bb61c309b1b /kernel/auditsc.c
parentf7b53637c090bd8ce2dc74ad0f3aa1898aff2524 (diff)
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audit: filter PATH records keyed on filesystem magic
Tracefs or debugfs were causing hundreds to thousands of PATH records to be associated with the init_module and finit_module SYSCALL records on a few modules when the following rule was in place for startup: -a always,exit -F arch=x86_64 -S init_module -F key=mod-load Provide a method to ignore these large number of PATH records from overwhelming the logs if they are not of interest. Introduce a new filter list "AUDIT_FILTER_FS", with a new field type AUDIT_FSTYPE, which keys off the filesystem 4-octet hexadecimal magic identifier to filter specific filesystem PATH records. An example rule would look like: -a never,filesystem -F fstype=0x74726163 -F key=ignore_tracefs -a never,filesystem -F fstype=0x64626720 -F key=ignore_debugfs Arguably the better way to address this issue is to disable tracefs and debugfs on boot from production systems. See: https://github.com/linux-audit/audit-kernel/issues/16 See: https://github.com/linux-audit/audit-userspace/issues/8 Test case: https://github.com/linux-audit/audit-testsuite/issues/42 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: fixed the whitespace damage in kernel/auditsc.c] Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'kernel/auditsc.c')
-rw-r--r--kernel/auditsc.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index aac1a41f82bd..c9bb29e17335 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1869,10 +1869,33 @@ void __audit_inode_child(struct inode *parent,
struct inode *inode = d_backing_inode(dentry);
const char *dname = dentry->d_name.name;
struct audit_names *n, *found_parent = NULL, *found_child = NULL;
+ struct audit_entry *e;
+ struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS];
+ int i;
if (!context->in_syscall)
return;
+ rcu_read_lock();
+ if (!list_empty(list)) {
+ list_for_each_entry_rcu(e, list, list) {
+ for (i = 0; i < e->rule.field_count; i++) {
+ struct audit_field *f = &e->rule.fields[i];
+
+ if (f->type == AUDIT_FSTYPE) {
+ if (audit_comparator(parent->i_sb->s_magic,
+ f->op, f->val)) {
+ if (e->rule.action == AUDIT_NEVER) {
+ rcu_read_unlock();
+ return;
+ }
+ }
+ }
+ }
+ }
+ }
+ rcu_read_unlock();
+
if (inode)
handle_one(inode);