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selftests/bpf: Allow to use kfunc from testmod.ko in test_verifier

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Currently the test_verifier allows test to specify kfunc symbol
and search for it in the kernel BTF.

Adding the possibility to search for kfunc also in bpf_testmod
module when it's not found in kernel BTF.

To find bpf_testmod btf we need to get back SYS_ADMIN cap.

Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230515133756.1658301-9-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jiri Olsa 2023-05-15 15:37:54 +02:00 committed by Alexei Starovoitov
parent b23b385fa1
commit f26ebdd3e4
1 changed files with 139 additions and 22 deletions
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161
tools/testing/selftests/bpf/test_verifier.c
View file

@ -874,8 +874,140 @@ static int create_map_kptr(void)
return fd;
}
static void set_root(bool set)
{
__u64 caps;
if (set) {
if (cap_enable_effective(1ULL << CAP_SYS_ADMIN, &caps))
perror("cap_disable_effective(CAP_SYS_ADMIN)");
} else {
if (cap_disable_effective(1ULL << CAP_SYS_ADMIN, &caps))
perror("cap_disable_effective(CAP_SYS_ADMIN)");
}
}
static __u64 ptr_to_u64(const void *ptr)
{
return (uintptr_t) ptr;
}
static struct btf *btf__load_testmod_btf(struct btf *vmlinux)
{
struct bpf_btf_info info;
__u32 len = sizeof(info);
struct btf *btf = NULL;
char name[64];
__u32 id = 0;
int err, fd;
/* Iterate all loaded BTF objects and find bpf_testmod,
* we need SYS_ADMIN cap for that.
*/
set_root(true);
while (true) {
err = bpf_btf_get_next_id(id, &id);
if (err) {
if (errno == ENOENT)
break;
perror("bpf_btf_get_next_id failed");
break;
}
fd = bpf_btf_get_fd_by_id(id);
if (fd < 0) {
if (errno == ENOENT)
continue;
perror("bpf_btf_get_fd_by_id failed");
break;
}
memset(&info, 0, sizeof(info));
info.name_len = sizeof(name);
info.name = ptr_to_u64(name);
len = sizeof(info);
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err) {
close(fd);
perror("bpf_obj_get_info_by_fd failed");
break;
}
if (strcmp("bpf_testmod", name)) {
close(fd);
continue;
}
btf = btf__load_from_kernel_by_id_split(id, vmlinux);
if (!btf) {
close(fd);
break;
}
/* We need the fd to stay open so it can be used in fd_array.
* The final cleanup call to btf__free will free btf object
* and close the file descriptor.
*/
btf__set_fd(btf, fd);
break;
}
set_root(false);
return btf;
}
static struct btf *testmod_btf;
static struct btf *vmlinux_btf;
static void kfuncs_cleanup(void)
{
btf__free(testmod_btf);
btf__free(vmlinux_btf);
}
static void fixup_prog_kfuncs(struct bpf_insn *prog, int *fd_array,
struct kfunc_btf_id_pair *fixup_kfunc_btf_id)
{
/* Patch in kfunc BTF IDs */
while (fixup_kfunc_btf_id->kfunc) {
int btf_id = 0;
/* try to find kfunc in kernel BTF */
vmlinux_btf = vmlinux_btf ?: btf__load_vmlinux_btf();
if (vmlinux_btf) {
btf_id = btf__find_by_name_kind(vmlinux_btf,
fixup_kfunc_btf_id->kfunc,
BTF_KIND_FUNC);
btf_id = btf_id < 0 ? 0 : btf_id;
}
/* kfunc not found in kernel BTF, try bpf_testmod BTF */
if (!btf_id) {
testmod_btf = testmod_btf ?: btf__load_testmod_btf(vmlinux_btf);
if (testmod_btf) {
btf_id = btf__find_by_name_kind(testmod_btf,
fixup_kfunc_btf_id->kfunc,
BTF_KIND_FUNC);
btf_id = btf_id < 0 ? 0 : btf_id;
if (btf_id) {
/* We put bpf_testmod module fd into fd_array
* and its index 1 into instruction 'off'.
*/
*fd_array = btf__fd(testmod_btf);
prog[fixup_kfunc_btf_id->insn_idx].off = 1;
}
}
}
prog[fixup_kfunc_btf_id->insn_idx].imm = btf_id;
fixup_kfunc_btf_id++;
}
}
static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
struct bpf_insn *prog, int *map_fds)
struct bpf_insn *prog, int *map_fds, int *fd_array)
{
int *fixup_map_hash_8b = test->fixup_map_hash_8b;
int *fixup_map_hash_48b = test->fixup_map_hash_48b;
@ -900,7 +1032,6 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
int *fixup_map_ringbuf = test->fixup_map_ringbuf;
int *fixup_map_timer = test->fixup_map_timer;
int *fixup_map_kptr = test->fixup_map_kptr;
struct kfunc_btf_id_pair *fixup_kfunc_btf_id = test->fixup_kfunc_btf_id;
if (test->fill_helper) {
test->fill_insns = calloc(MAX_TEST_INSNS, sizeof(struct bpf_insn));
@ -1101,25 +1232,7 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
} while (*fixup_map_kptr);
}
/* Patch in kfunc BTF IDs */
if (fixup_kfunc_btf_id->kfunc) {
struct btf *btf;
int btf_id;
do {
btf_id = 0;
btf = btf__load_vmlinux_btf();
if (btf) {
btf_id = btf__find_by_name_kind(btf,
fixup_kfunc_btf_id->kfunc,
BTF_KIND_FUNC);
btf_id = btf_id < 0 ? 0 : btf_id;
}
btf__free(btf);
prog[fixup_kfunc_btf_id->insn_idx].imm = btf_id;
fixup_kfunc_btf_id++;
} while (fixup_kfunc_btf_id->kfunc);
}
fixup_prog_kfuncs(prog, fd_array, test->fixup_kfunc_btf_id);
}
struct libcap {
@ -1446,6 +1559,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
int run_errs, run_successes;
int map_fds[MAX_NR_MAPS];
const char *expected_err;
int fd_array[2] = { -1, -1 };
int saved_errno;
int fixup_skips;
__u32 pflags;
@ -1459,7 +1573,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
if (!prog_type)
prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
fixup_skips = skips;
do_test_fixup(test, prog_type, prog, map_fds);
do_test_fixup(test, prog_type, prog, map_fds, &fd_array[1]);
if (test->fill_insns) {
prog = test->fill_insns;
prog_len = test->prog_len;
@ -1493,6 +1607,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
else
opts.log_level = DEFAULT_LIBBPF_LOG_LEVEL;
opts.prog_flags = pflags;
if (fd_array[1] != -1)
opts.fd_array = &fd_array[0];
if ((prog_type == BPF_PROG_TYPE_TRACING ||
prog_type == BPF_PROG_TYPE_LSM) && test->kfunc) {
@ -1719,6 +1835,7 @@ static int do_test(bool unpriv, unsigned int from, unsigned int to)
}
unload_bpf_testmod(verbose);
kfuncs_cleanup();
printf("Summary: %d PASSED, %d SKIPPED, %d FAILED\n", passes,
skips, errors);