lkml.org 
[lkml]   [2019]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC v1 08/14] krsi: Show attached program names in hook read handler.
Date
From: KP Singh <kpsingh@google.com>

For inspectability the system administrator should be able to view the
list of active KRSI programs:

bash # cat /sys/kernel/security/krsi/process_execution
bpf_prog1

Signed-off-by: KP Singh <kpsingh@google.com>
---
security/krsi/krsi_fs.c | 76 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 75 insertions(+), 1 deletion(-)

diff --git a/security/krsi/krsi_fs.c b/security/krsi/krsi_fs.c
index 3ba18b52ce85..0ebf4fabe935 100644
--- a/security/krsi/krsi_fs.c
+++ b/security/krsi/krsi_fs.c
@@ -6,6 +6,7 @@
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/filter.h>
+#include <linux/seq_file.h>
#include <linux/bpf.h>
#include <linux/security.h>

@@ -16,8 +17,81 @@ extern struct krsi_hook krsi_hooks_list[];

static struct dentry *krsi_dir;

+static void *seq_start(struct seq_file *m, loff_t *pos)
+ __acquires(rcu)
+{
+ struct krsi_hook *h;
+ struct dentry *dentry;
+ struct bpf_prog_array *progs;
+ struct bpf_prog_array_item *item;
+
+ /*
+ * rcu_read_lock() must be held before any return statement
+ * because the stop() will always be called and thus call
+ * rcu_read_unlock()
+ */
+ rcu_read_lock();
+
+ dentry = file_dentry(m->file);
+ h = dentry->d_fsdata;
+ if (WARN_ON(!h))
+ return ERR_PTR(-EFAULT);
+
+ progs = rcu_dereference(h->progs);
+ if ((*pos) >= bpf_prog_array_length(progs))
+ return NULL;
+
+ item = progs->items + *pos;
+ if (!item->prog)
+ return NULL;
+
+ return item;
+}
+
+static void *seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ struct bpf_prog_array_item *item = v;
+
+ item++;
+ ++*pos;
+
+ if (!item->prog)
+ return NULL;
+
+ return item;
+}
+
+static void seq_stop(struct seq_file *m, void *v)
+ __releases(rcu)
+{
+ rcu_read_unlock();
+}
+
+static int show_prog(struct seq_file *m, void *v)
+{
+ struct bpf_prog_array_item *item = v;
+
+ seq_printf(m, "%s\n", item->prog->aux->name);
+ return 0;
+}
+
+static const struct seq_operations seq_ops = {
+ .show = show_prog,
+ .start = seq_start,
+ .next = seq_next,
+ .stop = seq_stop,
+};
+
+static int hook_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &seq_ops);
+}
+
static const struct file_operations krsi_hook_ops = {
- .llseek = generic_file_llseek,
+ .open = hook_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
};

int krsi_fs_initialized;
--
2.20.1
\
 
 \ /
  Last update: 2019-09-10 13:57    [W:0.114 / U:1.628 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site