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Revision 11bbd8b416f8abf40900dc5041152892f873d915 authored by Michal Koutný on 01 June 2019, 05:30:16 UTC, committed by Linus Torvalds on 01 June 2019, 22:51:31 UTC 
prctl_set_mm: refactor checks from validate_prctl_map
 
Despite comment of validate_prctl_map claims there are no capability
checks, it is not completely true since commit 4d28df6152aa ("prctl: Allow
local CAP_SYS_ADMIN changing exe_file").  Extract the check out of the
function and make the function perform purely arithmetic checks.

This patch should not change any behavior, it is mere refactoring for
following patch.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20190502125203.24014-2-mkoutny@suse.com
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 8856ae4
Raw File
tracex4_kern.c 
/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"

struct pair {
	u64 val;
	u64 ip;
};

struct bpf_map_def SEC("maps") my_map = {
	.type = BPF_MAP_TYPE_HASH,
	.key_size = sizeof(long),
	.value_size = sizeof(struct pair),
	.max_entries = 1000000,
};

/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
 * example will no longer be meaningful
 */
SEC("kprobe/kmem_cache_free")
int bpf_prog1(struct pt_regs *ctx)
{
	long ptr = PT_REGS_PARM2(ctx);

	bpf_map_delete_elem(&my_map, &ptr);
	return 0;
}

SEC("kretprobe/kmem_cache_alloc_node")
int bpf_prog2(struct pt_regs *ctx)
{
	long ptr = PT_REGS_RC(ctx);
	long ip = 0;

	/* get ip address of kmem_cache_alloc_node() caller */
	BPF_KRETPROBE_READ_RET_IP(ip, ctx);

	struct pair v = {
		.val = bpf_ktime_get_ns(),
		.ip = ip,
	};

	bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY);
	return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;
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