[PATCH ghak100 V2 1/2] 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(a)redhat.com&gt; --- kernel/auditsc.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index b585ceb2f7a2..3d05d5fc6240 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1763,10 +1763,31 @@ 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; @@ -1875,14 +1896,12 @@ 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; } } } -- 1.8.3.1