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authorRichard Guy Briggs <rgb@redhat.com>2019-01-23 13:34:59 -0500
committerPaul Moore <paul@paul-moore.com>2019-01-25 16:12:55 -0500
commita252f56a3c922197ef40dce8f8cc258ae75e0193 (patch)
tree76998437c6dc721ac70e480ccc5081aa0ed52d01 /kernel/auditsc.c
parent2fec30e245a3b46fef89c4cb1f74eefc5fbb29a6 (diff)
audit: more filter PATH records keyed on filesystem magic
Like commit 42d5e37654e4 ("audit: filter PATH records keyed on filesystem magic") that addresses https://github.com/linux-audit/audit-kernel/issues/8 Any user or remote filesystem could become unavailable and effectively block on a forced unmount. -a always,exit -S umount2 -F key=umount2 Provide a method to ignore these user and remote filesystems to prevent them from being impossible to unmount. Extend the "AUDIT_FILTER_FS" filter that uses the field type AUDIT_FSTYPE keying off the filesystem 4-octet hexadecimal magic identifier to filter specific filesystems to cover audit_inode() to address this blockage. An example rule would look like: -a never,filesystem -F fstype=0x517B -F key=ignore_smb -a never,filesystem -F fstype=0x6969 -F key=ignore_nfs Arguably the better way to address this issue is to disable auditing processes that touch removable filesystems. Note: refactor __audit_inode_child() to remove two levels of if indentation. Please see the github issue tracker https://github.com/linux-audit/audit-kernel/issues/100 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'kernel/auditsc.c')
-rw-r--r--kernel/auditsc.c35
1 files changed, 27 insertions, 8 deletions
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index c16beb25fd0a..a2696ce790f9 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1766,10 +1766,31 @@ void __audit_inode(struct filename *name, const struct dentry *dentry,
struct inode *inode = d_backing_inode(dentry);
struct audit_names *n;
bool parent = flags & AUDIT_INODE_PARENT;
+ 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
+ && audit_comparator(inode->i_sb->s_magic,
+ f->op, f->val)
+ && e->rule.action == AUDIT_NEVER) {
+ rcu_read_unlock();
+ return;
+ }
+ }
+ }
+ }
+ rcu_read_unlock();
+
if (!name)
goto out_alloc;
@@ -1878,14 +1899,12 @@ void __audit_inode_child(struct inode *parent,
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;
- }
- }
+ if (f->type == AUDIT_FSTYPE
+ && audit_comparator(parent->i_sb->s_magic,
+ f->op, f->val)
+ && e->rule.action == AUDIT_NEVER) {
+ rcu_read_unlock();
+ return;
}
}
}