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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stacktrace_build_id.c (3361B)


      1// SPDX-License-Identifier: GPL-2.0
      2#include <test_progs.h>
      3#include "test_stacktrace_build_id.skel.h"
      4
      5void test_stacktrace_build_id(void)
      6{
      7
      8	int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
      9	struct test_stacktrace_build_id *skel;
     10	int err, stack_trace_len;
     11	__u32 key, prev_key, val, duration = 0;
     12	char buf[256];
     13	int i, j;
     14	struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
     15	int build_id_matches = 0;
     16	int retry = 1;
     17
     18retry:
     19	skel = test_stacktrace_build_id__open_and_load();
     20	if (CHECK(!skel, "skel_open_and_load", "skeleton open/load failed\n"))
     21		return;
     22
     23	err = test_stacktrace_build_id__attach(skel);
     24	if (CHECK(err, "attach_tp", "err %d\n", err))
     25		goto cleanup;
     26
     27	/* find map fds */
     28	control_map_fd = bpf_map__fd(skel->maps.control_map);
     29	stackid_hmap_fd = bpf_map__fd(skel->maps.stackid_hmap);
     30	stackmap_fd = bpf_map__fd(skel->maps.stackmap);
     31	stack_amap_fd = bpf_map__fd(skel->maps.stack_amap);
     32
     33	if (CHECK_FAIL(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")))
     34		goto cleanup;
     35	if (CHECK_FAIL(system("./urandom_read")))
     36		goto cleanup;
     37	/* disable stack trace collection */
     38	key = 0;
     39	val = 1;
     40	bpf_map_update_elem(control_map_fd, &key, &val, 0);
     41
     42	/* for every element in stackid_hmap, we can find a corresponding one
     43	 * in stackmap, and vise versa.
     44	 */
     45	err = compare_map_keys(stackid_hmap_fd, stackmap_fd);
     46	if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap",
     47		  "err %d errno %d\n", err, errno))
     48		goto cleanup;
     49
     50	err = compare_map_keys(stackmap_fd, stackid_hmap_fd);
     51	if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap",
     52		  "err %d errno %d\n", err, errno))
     53		goto cleanup;
     54
     55	err = extract_build_id(buf, 256);
     56
     57	if (CHECK(err, "get build_id with readelf",
     58		  "err %d errno %d\n", err, errno))
     59		goto cleanup;
     60
     61	err = bpf_map__get_next_key(skel->maps.stackmap, NULL, &key, sizeof(key));
     62	if (CHECK(err, "get_next_key from stackmap",
     63		  "err %d, errno %d\n", err, errno))
     64		goto cleanup;
     65
     66	do {
     67		char build_id[64];
     68
     69		err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs);
     70		if (CHECK(err, "lookup_elem from stackmap",
     71			  "err %d, errno %d\n", err, errno))
     72			goto cleanup;
     73		for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
     74			if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
     75			    id_offs[i].offset != 0) {
     76				for (j = 0; j < 20; ++j)
     77					sprintf(build_id + 2 * j, "%02x",
     78						id_offs[i].build_id[j] & 0xff);
     79				if (strstr(buf, build_id) != NULL)
     80					build_id_matches = 1;
     81			}
     82		prev_key = key;
     83	} while (bpf_map__get_next_key(skel->maps.stackmap, &prev_key, &key, sizeof(key)) == 0);
     84
     85	/* stack_map_get_build_id_offset() is racy and sometimes can return
     86	 * BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
     87	 * try it one more time.
     88	 */
     89	if (build_id_matches < 1 && retry--) {
     90		test_stacktrace_build_id__destroy(skel);
     91		printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
     92		       __func__);
     93		goto retry;
     94	}
     95
     96	if (CHECK(build_id_matches < 1, "build id match",
     97		  "Didn't find expected build ID from the map\n"))
     98		goto cleanup;
     99
    100	stack_trace_len = PERF_MAX_STACK_DEPTH *
    101			  sizeof(struct bpf_stack_build_id);
    102	err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);
    103	CHECK(err, "compare_stack_ips stackmap vs. stack_amap",
    104	      "err %d errno %d\n", err, errno);
    105
    106cleanup:
    107	test_stacktrace_build_id__destroy(skel);
    108}