From: Carlos Neira <cneirabustos@gmail.com>
To: netdev@vger.kernel.org
Cc: yhs@fb.com, ebiederm@xmission.com, brouer@redhat.com,
bpf@vger.kernel.org, cneirabustos@gmail.com
Subject: [PATCH V12 2/4] bpf: added new helper bpf_get_ns_current_pid_tgid
Date: Tue, 1 Oct 2019 18:41:39 -0300 [thread overview]
Message-ID: <20191001214141.6294-3-cneirabustos@gmail.com> (raw)
In-Reply-To: <20191001214141.6294-1-cneirabustos@gmail.com>
New bpf helper bpf_get_ns_current_pid_tgid,
This helper will return pid and tgid from current task
which namespace matches dev_t and inode number provided,
this will allows us to instrument a process inside a container.
Signed-off-by: Carlos Neira <cneirabustos@gmail.com>
---
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 18 +++++++++++++++++-
kernel/bpf/core.c | 1 +
kernel/bpf/helpers.c | 36 ++++++++++++++++++++++++++++++++++++
kernel/trace/bpf_trace.c | 2 ++
5 files changed, 57 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 5b9d22338606..231001475504 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1055,6 +1055,7 @@ extern const struct bpf_func_proto bpf_get_local_storage_proto;
extern const struct bpf_func_proto bpf_strtol_proto;
extern const struct bpf_func_proto bpf_strtoul_proto;
extern const struct bpf_func_proto bpf_tcp_sock_proto;
+extern const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto;
/* Shared helpers among cBPF and eBPF. */
void bpf_user_rnd_init_once(void);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 77c6be96d676..ea8145d7f897 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2750,6 +2750,21 @@ union bpf_attr {
* **-EOPNOTSUPP** kernel configuration does not enable SYN cookies
*
* **-EPROTONOSUPPORT** IP packet version is not 4 or 6
+ *
+ * u64 bpf_get_ns_current_pid_tgid(u64 dev, u64 inum)
+ * Return
+ * A 64-bit integer containing the current tgid and pid from current task
+ * which namespace inode and dev_t matches , and is create as such:
+ * *current_task*\ **->tgid << 32 \|**
+ * *current_task*\ **->pid**.
+ *
+ * On failure, the returned value is one of the following:
+ *
+ * **-EINVAL** if dev and inum supplied don't match dev_t and inode number
+ * with nsfs of current task, or if dev conversion to dev_t lost high bits.
+ *
+ * **-ENOENT** if /proc/self/ns does not exists.
+ *
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -2862,7 +2877,8 @@ union bpf_attr {
FN(sk_storage_get), \
FN(sk_storage_delete), \
FN(send_signal), \
- FN(tcp_gen_syncookie),
+ FN(tcp_gen_syncookie), \
+ FN(get_ns_current_pid_tgid),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 66088a9e9b9e..b2fd5358f472 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2042,6 +2042,7 @@ const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
const struct bpf_func_proto bpf_get_current_comm_proto __weak;
const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
const struct bpf_func_proto bpf_get_local_storage_proto __weak;
+const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
{
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 5e28718928ca..8777181d1717 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -11,6 +11,8 @@
#include <linux/uidgid.h>
#include <linux/filter.h>
#include <linux/ctype.h>
+#include <linux/pid_namespace.h>
+#include <linux/proc_ns.h>
#include "../../lib/kstrtox.h"
@@ -487,3 +489,37 @@ const struct bpf_func_proto bpf_strtoul_proto = {
.arg4_type = ARG_PTR_TO_LONG,
};
#endif
+
+BPF_CALL_2(bpf_get_ns_current_pid_tgid, u64, dev, u64, inum)
+{
+ struct task_struct *task = current;
+ struct pid_namespace *pidns;
+ pid_t pid, tgid;
+
+ if ((u64)(dev_t)dev != dev)
+ return -EINVAL;
+
+ if (unlikely(!task))
+ return -EINVAL;
+
+ pidns = task_active_pid_ns(task);
+ if (unlikely(!pidns))
+ return -ENOENT;
+
+
+ if (!ns_match(&pidns->ns, (dev_t)dev, inum))
+ return -EINVAL;
+
+ pid = task_pid_nr_ns(task, pidns);
+ tgid = task_tgid_nr_ns(task, pidns);
+
+ return (u64) tgid << 32 | pid;
+}
+
+const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto = {
+ .func = bpf_get_ns_current_pid_tgid,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_ANYTHING,
+ .arg2_type = ARG_ANYTHING,
+};
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 44bd08f2443b..32331a1dcb6d 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -735,6 +735,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
#endif
case BPF_FUNC_send_signal:
return &bpf_send_signal_proto;
+ case BPF_FUNC_get_ns_current_pid_tgid:
+ return &bpf_get_ns_current_pid_tgid_proto;
default:
return NULL;
}
--
2.20.1
next prev parent reply other threads:[~2019-10-01 21:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-01 21:41 [PATCH V12 0/4] BPF: New helper to obtain namespace data from current task Carlos Neira
2019-10-01 21:41 ` [PATCH V12 1/4] fs/nsfs.c: added ns_match Carlos Neira
2019-10-01 21:41 ` Carlos Neira [this message]
2019-10-02 10:52 ` [PATCH V12 2/4] bpf: added new helper bpf_get_ns_current_pid_tgid Daniel Borkmann
2019-10-03 14:52 ` Carlos Antonio Neira Bustos
2019-10-03 17:30 ` Andrii Nakryiko
2019-10-03 18:12 ` Carlos Antonio Neira Bustos
2019-10-01 21:41 ` [PATCH V12 3/4] tools: Added bpf_get_ns_current_pid_tgid helper Carlos Neira
2019-10-01 21:41 ` [PATCH V12 4/4] tools/testing/selftests/bpf: Add self-tests for new helper Carlos Neira
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