Merge branch 'First set of verifier/*.c migrated to inline assembly'

Eduard Zingerman says:

====================

This is a follow up for RFC [1]. It migrates a first batch of 38
verifier/*.c tests to inline assembly and use of ./test_progs for
actual execution. The migration is done by a python script (see [2]).

Each migrated verifier/xxx.c file is mapped to progs/verifier_xxx.c
plus an entry in the prog_tests/verifier.c. One patch per each file.

A few patches at the beginning of the patch-set extend test_loader
with necessary functionality, mainly:
- support for tests execution in unprivileged mode;
- support for test runs for test programs.

Migrated tests could be selected for execution using the following filter:

  ./test_progs -a verifier_*

An example of the migrated test:

  SEC("xdp")
  __description("XDP pkt read, pkt_data' > pkt_end, corner case, good access")
  __success __retval(0) __flag(BPF_F_ANY_ALIGNMENT)
  __naked void end_corner_case_good_access_1(void)
  {
          asm volatile ("                                 \
          r2 = *(u32*)(r1 + %[xdp_md_data]);              \
          r3 = *(u32*)(r1 + %[xdp_md_data_end]);          \
          r1 = r2;                                        \
          r1 += 8;                                        \
          if r1 > r3 goto l0_%=;                          \
          r0 = *(u64*)(r1 - 8);                           \
  l0_%=:  r0 = 0;                                         \
          exit;                                           \
  "       :
          : __imm_const(xdp_md_data, offsetof(struct xdp_md, data)),
            __imm_const(xdp_md_data_end, offsetof(struct xdp_md, data_end))
          : __clobber_all);
  }

Changes compared to RFC:
- test_loader.c is extended to support test program runs;
- capabilities handling now matches behavior of test_verifier;
- BPF_ST_MEM instructions are automatically replaced by BPF_STX_MEM
  instructions to overcome current clang limitations;
- tests styling updates according to RFC feedback;
- 38 migrated files are included instead of 1.

I used the following means for testing:
- migration tool itself has a set of self-tests;
- migrated tests are passing;
- manually compared each old/new file side-by-side.

While doing side-by-side comparison I've noted a few defects in the
original tests:
- and.c:
  - One of the jump targets is off by one;
  - BPF_ST_MEM wrong OFF/IMM ordering;
- array_access.c:
  - BPF_ST_MEM wrong OFF/IMM ordering;
- value_or_null.c:
  - BPF_ST_MEM wrong OFF/IMM ordering.

These defects would be addressed separately.

[1] RFC
    https://lore.kernel.org/bpf/20230123145148.2791939-1-eddyz87@gmail.com/
[2] Migration tool
    https://github.com/eddyz87/verifier-tests-migrator
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/verifier_basic_stack.c b/tools/testing/selftests/bpf/progs/verifier_basic_stack.c
new file mode 100644
index 000000000000..359df865a8f3
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/verifier_basic_stack.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Converted from tools/testing/selftests/bpf/verifier/basic_stack.c */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(max_entries, 1);
+	__type(key, long long);
+	__type(value, long long);
+} map_hash_8b SEC(".maps");
+
+SEC("socket")
+__description("stack out of bounds")
+__failure __msg("invalid write to stack")
+__failure_unpriv
+__naked void stack_out_of_bounds(void)
+{
+	asm volatile ("					\
+	r1 = 0;						\
+	*(u64*)(r10 + 8) = r1;				\
+	exit;						\
+"	::: __clobber_all);
+}
+
+SEC("socket")
+__description("uninitialized stack1")
+__failure __msg("invalid indirect read from stack")
+__failure_unpriv
+__naked void uninitialized_stack1(void)
+{
+	asm volatile ("					\
+	r2 = r10;					\
+	r2 += -8;					\
+	r1 = %[map_hash_8b] ll;				\
+	call %[bpf_map_lookup_elem];			\
+	exit;						\
+"	:
+	: __imm(bpf_map_lookup_elem),
+	  __imm_addr(map_hash_8b)
+	: __clobber_all);
+}
+
+SEC("socket")
+__description("uninitialized stack2")
+__failure __msg("invalid read from stack")
+__failure_unpriv
+__naked void uninitialized_stack2(void)
+{
+	asm volatile ("					\
+	r2 = r10;					\
+	r0 = *(u64*)(r2 - 8);				\
+	exit;						\
+"	::: __clobber_all);
+}
+
+SEC("socket")
+__description("invalid fp arithmetic")
+__failure __msg("R1 subtraction from stack pointer")
+__failure_unpriv
+__naked void invalid_fp_arithmetic(void)
+{
+	/* If this gets ever changed, make sure JITs can deal with it. */
+	asm volatile ("					\
+	r0 = 0;						\
+	r1 = r10;					\
+	r1 -= 8;					\
+	*(u64*)(r1 + 0) = r0;				\
+	exit;						\
+"	::: __clobber_all);
+}
+
+SEC("socket")
+__description("non-invalid fp arithmetic")
+__success __success_unpriv __retval(0)
+__naked void non_invalid_fp_arithmetic(void)
+{
+	asm volatile ("					\
+	r0 = 0;						\
+	*(u64*)(r10 - 8) = r0;				\
+	exit;						\
+"	::: __clobber_all);
+}
+
+SEC("socket")
+__description("misaligned read from stack")
+__failure __msg("misaligned stack access")
+__failure_unpriv
+__naked void misaligned_read_from_stack(void)
+{
+	asm volatile ("					\
+	r2 = r10;					\
+	r0 = *(u64*)(r2 - 4);				\
+	exit;						\
+"	::: __clobber_all);
+}
+
+char _license[] SEC("license") = "GPL";