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authorAlexei Starovoitov <ast@plumgrid.com>2015-06-12 19:39:12 -0700
committerDavid S. Miller <davem@davemloft.net>2015-06-15 15:53:50 -0700
commitffeedafbf0236f03aeb2e8db273b3e5ae5f5bc89 (patch)
treee00f1b0bba1c217afbcf4dda00ef950afdfcafbc /kernel/bpf
parentada6c1de9ecabcfc5619479bcd29a208f2e248a0 (diff)
downloadlinux-sh-ffeedafbf0236f03aeb2e8db273b3e5ae5f5bc89.tar.gz
bpf: introduce current->pid, tgid, uid, gid, comm accessors
eBPF programs attached to kprobes need to filter based on current->pid, uid and other fields, so introduce helper functions: u64 bpf_get_current_pid_tgid(void) Return: current->tgid << 32 | current->pid u64 bpf_get_current_uid_gid(void) Return: current_gid << 32 | current_uid bpf_get_current_comm(char *buf, int size_of_buf) stores current->comm into buf They can be used from the programs attached to TC as well to classify packets based on current task fields. Update tracex2 example to print histogram of write syscalls for each process instead of aggregated for all. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/core.c3
-rw-r--r--kernel/bpf/helpers.c58
2 files changed, 61 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 1e00aa3316dc..1fc45cc83076 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -730,6 +730,9 @@ const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
+const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
+const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
+const struct bpf_func_proto bpf_get_current_comm_proto __weak;
/* Always built-in helper functions. */
const struct bpf_func_proto bpf_tail_call_proto = {
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 7ad5d8842d5b..1447ec09421e 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -14,6 +14,8 @@
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/ktime.h>
+#include <linux/sched.h>
+#include <linux/uidgid.h>
/* If kernel subsystem is allowing eBPF programs to call this function,
* inside its own verifier_ops->get_func_proto() callback it should return
@@ -124,3 +126,59 @@ const struct bpf_func_proto bpf_ktime_get_ns_proto = {
.gpl_only = true,
.ret_type = RET_INTEGER,
};
+
+static u64 bpf_get_current_pid_tgid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+ struct task_struct *task = current;
+
+ if (!task)
+ return -EINVAL;
+
+ return (u64) task->tgid << 32 | task->pid;
+}
+
+const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
+ .func = bpf_get_current_pid_tgid,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+};
+
+static u64 bpf_get_current_uid_gid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+ struct task_struct *task = current;
+ kuid_t uid;
+ kgid_t gid;
+
+ if (!task)
+ return -EINVAL;
+
+ current_uid_gid(&uid, &gid);
+ return (u64) from_kgid(&init_user_ns, gid) << 32 |
+ from_kuid(&init_user_ns, uid);
+}
+
+const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
+ .func = bpf_get_current_uid_gid,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+};
+
+static u64 bpf_get_current_comm(u64 r1, u64 size, u64 r3, u64 r4, u64 r5)
+{
+ struct task_struct *task = current;
+ char *buf = (char *) (long) r1;
+
+ if (!task)
+ return -EINVAL;
+
+ memcpy(buf, task->comm, min_t(size_t, size, sizeof(task->comm)));
+ return 0;
+}
+
+const struct bpf_func_proto bpf_get_current_comm_proto = {
+ .func = bpf_get_current_comm,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_STACK,
+ .arg2_type = ARG_CONST_STACK_SIZE,
+};