Commit 9f42c8b3 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'bpf-share-helpers' 



Alexei Starovoitov says:

====================
v1->v2: switched to init_user_ns from current_user_ns as suggested by Andy

Introduce new helpers to access 'struct task_struct'->pid, tgid, uid, gid, comm
fields in tracing and networking.

Share bpf_trace_printk() and bpf_get_smp_processor_id() helpers between
tracing and networking.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents ada6c1de ab1973d3

include/linux/bpf.h

+4 −0
Original line number Diff line number Diff line
@@ -150,6 +150,7 @@ struct bpf_array { 
u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);

void bpf_prog_array_map_clear(struct bpf_map *map);

bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);

const struct bpf_func_proto *bpf_get_trace_printk_proto(void);



#ifdef CONFIG_BPF_SYSCALL

void bpf_register_prog_type(struct bpf_prog_type_list *tl);
@@ -188,5 +189,8 @@ extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 
extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;

extern const struct bpf_func_proto bpf_tail_call_proto;

extern const struct bpf_func_proto bpf_ktime_get_ns_proto;

extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;

extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;

extern const struct bpf_func_proto bpf_get_current_comm_proto;



#endif /* _LINUX_BPF_H */

include/uapi/linux/bpf.h

+19 −0
Original line number Diff line number Diff line
@@ -230,6 +230,25 @@ enum bpf_func_id { 
	 * Return: 0 on success

	 */

	BPF_FUNC_clone_redirect,



	/**

	 * u64 bpf_get_current_pid_tgid(void)

	 * Return: current->tgid << 32 | current->pid

	 */

	BPF_FUNC_get_current_pid_tgid,



	/**

	 * u64 bpf_get_current_uid_gid(void)

	 * Return: current_gid << 32 | current_uid

	 */

	BPF_FUNC_get_current_uid_gid,



	/**

	 * bpf_get_current_comm(char *buf, int size_of_buf)

	 * stores current->comm into buf

	 * Return: 0 on success

	 */

	BPF_FUNC_get_current_comm,

	__BPF_FUNC_MAX_ID,

};

kernel/bpf/core.c

+7 −0
Original line number Diff line number Diff line
@@ -730,6 +730,13 @@ 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;

const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)

{

	return NULL;

}



/* Always built-in helper functions. */

const struct bpf_func_proto bpf_tail_call_proto = {

kernel/bpf/helpers.c

+58 −0
Original line number Diff line number Diff line
@@ -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,

};

kernel/trace/bpf_trace.c

+20 −8
Original line number Diff line number Diff line
@@ -147,6 +147,17 @@ static const struct bpf_func_proto bpf_trace_printk_proto = { 
	.arg2_type	= ARG_CONST_STACK_SIZE,

};



const struct bpf_func_proto *bpf_get_trace_printk_proto(void)

{

	/*

	 * this program might be calling bpf_trace_printk,

	 * so allocate per-cpu printk buffers

	 */

	trace_printk_init_buffers();



	return &bpf_trace_printk_proto;

}



static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)

{

	switch (func_id) {
@@ -162,15 +173,16 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func 
		return &bpf_ktime_get_ns_proto;

	case BPF_FUNC_tail_call:

		return &bpf_tail_call_proto;



	case BPF_FUNC_get_current_pid_tgid:

		return &bpf_get_current_pid_tgid_proto;

	case BPF_FUNC_get_current_uid_gid:

		return &bpf_get_current_uid_gid_proto;

	case BPF_FUNC_get_current_comm:

		return &bpf_get_current_comm_proto;

	case BPF_FUNC_trace_printk:

		/*

		 * this program might be calling bpf_trace_printk,

		 * so allocate per-cpu printk buffers

		 */

		trace_printk_init_buffers();



		return &bpf_trace_printk_proto;

		return bpf_get_trace_printk_proto();

	case BPF_FUNC_get_smp_processor_id:

		return &bpf_get_smp_processor_id_proto;

	default:

		return NULL;

	}

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