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authorCarlos Neira <cneirabustos@gmail.com>2020-03-04 17:41:56 -0300
committerAlexei Starovoitov <ast@kernel.org>2020-03-12 17:33:11 -0700
commitb4490c5c4e023f09b7d27c9a9d3e7ad7d09ea6bf (patch)
tree2a1bcba2ff5a85b3fb0e0013b01ac25eef4cc6fa /kernel/bpf
parent1e2328e762548c7d17b7ba8ded9f409d05710dd1 (diff)
downloadlinux-next-b4490c5c4e023f09b7d27c9a9d3e7ad7d09ea6bf.tar.gz
bpf: Added new helper bpf_get_ns_current_pid_tgid
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> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200304204157.58695-3-cneirabustos@gmail.com
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/core.c1
-rw-r--r--kernel/bpf/helpers.c45
2 files changed, 46 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 973a20d49749..0f9ca46e1978 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2149,6 +2149,7 @@ 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 d8b7b110a1c5..01878db15eaf 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -12,6 +12,8 @@
#include <linux/filter.h>
#include <linux/ctype.h>
#include <linux/jiffies.h>
+#include <linux/pid_namespace.h>
+#include <linux/proc_ns.h>
#include "../../lib/kstrtox.h"
@@ -499,3 +501,46 @@ const struct bpf_func_proto bpf_strtoul_proto = {
.arg4_type = ARG_PTR_TO_LONG,
};
#endif
+
+BPF_CALL_4(bpf_get_ns_current_pid_tgid, u64, dev, u64, ino,
+ struct bpf_pidns_info *, nsdata, u32, size)
+{
+ struct task_struct *task = current;
+ struct pid_namespace *pidns;
+ int err = -EINVAL;
+
+ if (unlikely(size != sizeof(struct bpf_pidns_info)))
+ goto clear;
+
+ if (unlikely((u64)(dev_t)dev != dev))
+ goto clear;
+
+ if (unlikely(!task))
+ goto clear;
+
+ pidns = task_active_pid_ns(task);
+ if (unlikely(!pidns)) {
+ err = -ENOENT;
+ goto clear;
+ }
+
+ if (!ns_match(&pidns->ns, (dev_t)dev, ino))
+ goto clear;
+
+ nsdata->pid = task_pid_nr_ns(task, pidns);
+ nsdata->tgid = task_tgid_nr_ns(task, pidns);
+ return 0;
+clear:
+ memset((void *)nsdata, 0, (size_t) size);
+ return err;
+}
+
+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,
+ .arg3_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg4_type = ARG_CONST_SIZE,
+};