cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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bpf_iter_task.c (1932B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (c) 2020 Facebook */
      3#include "bpf_iter.h"
      4#include <bpf/bpf_helpers.h>
      5#include <bpf/bpf_tracing.h>
      6
      7char _license[] SEC("license") = "GPL";
      8
      9SEC("iter/task")
     10int dump_task(struct bpf_iter__task *ctx)
     11{
     12	struct seq_file *seq = ctx->meta->seq;
     13	struct task_struct *task = ctx->task;
     14	static char info[] = "    === END ===";
     15
     16	if (task == (void *)0) {
     17		BPF_SEQ_PRINTF(seq, "%s\n", info);
     18		return 0;
     19	}
     20
     21	if (ctx->meta->seq_num == 0)
     22		BPF_SEQ_PRINTF(seq, "    tgid      gid\n");
     23
     24	BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid);
     25	return 0;
     26}
     27
     28int num_expected_failure_copy_from_user_task = 0;
     29int num_success_copy_from_user_task = 0;
     30
     31SEC("iter.s/task")
     32int dump_task_sleepable(struct bpf_iter__task *ctx)
     33{
     34	struct seq_file *seq = ctx->meta->seq;
     35	struct task_struct *task = ctx->task;
     36	static const char info[] = "    === END ===";
     37	struct pt_regs *regs;
     38	void *ptr;
     39	uint32_t user_data = 0;
     40	int ret;
     41
     42	if (task == (void *)0) {
     43		BPF_SEQ_PRINTF(seq, "%s\n", info);
     44		return 0;
     45	}
     46
     47	/* Read an invalid pointer and ensure we get an error */
     48	ptr = NULL;
     49	ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
     50	if (ret) {
     51		++num_expected_failure_copy_from_user_task;
     52	} else {
     53		BPF_SEQ_PRINTF(seq, "%s\n", info);
     54		return 0;
     55	}
     56
     57	/* Try to read the contents of the task's instruction pointer from the
     58	 * remote task's address space.
     59	 */
     60	regs = (struct pt_regs *)bpf_task_pt_regs(task);
     61	if (regs == (void *)0) {
     62		BPF_SEQ_PRINTF(seq, "%s\n", info);
     63		return 0;
     64	}
     65	ptr = (void *)PT_REGS_IP(regs);
     66
     67	ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
     68	if (ret) {
     69		BPF_SEQ_PRINTF(seq, "%s\n", info);
     70		return 0;
     71	}
     72	++num_success_copy_from_user_task;
     73
     74	if (ctx->meta->seq_num == 0)
     75		BPF_SEQ_PRINTF(seq, "    tgid      gid     data\n");
     76
     77	BPF_SEQ_PRINTF(seq, "%8d %8d %8d\n", task->tgid, task->pid, user_data);
     78	return 0;
     79}