Commit db123e42 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add test case for delta propagation 



Add a small BPF verifier test case to ensure that alu32 additions to
registers are not subject to linked scalar delta tracking.

  # ./vmtest.sh -- ./test_progs -t verifier_linked_scalars
  [...]
  ./test_progs -t verifier_linked_scalars
  [    1.413138] tsc: Refined TSC clocksource calibration: 3407.993 MHz
  [    1.413524] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fcd52370, max_idle_ns: 440795242006 ns
  [    1.414223] clocksource: Switched to clocksource tsc
  [    1.419640] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.420025] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  #500/1   verifier_linked_scalars/scalars: find linked scalars:OK
  #500     verifier_linked_scalars:OK
  Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED
  [    1.590858] ACPI: PM: Preparing to enter system sleep state S5
  [    1.591402] reboot: Power down
  [...]

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20241016134913.32249-3-daniel@iogearbox.net
parent 3e9e7087

tools/testing/selftests/bpf/prog_tests/verifier.c

+2 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include "verifier_ld_ind.skel.h"

#include "verifier_ldsx.skel.h"

#include "verifier_leak_ptr.skel.h"

#include "verifier_linked_scalars.skel.h"

#include "verifier_loops1.skel.h"

#include "verifier_lwt.skel.h"

#include "verifier_map_in_map.skel.h"
@@ -170,6 +171,7 @@ void test_verifier_jit_convergence(void) { RUN(verifier_jit_convergence); } 
void test_verifier_ld_ind(void)               { RUN(verifier_ld_ind); }

void test_verifier_ldsx(void)                  { RUN(verifier_ldsx); }

void test_verifier_leak_ptr(void)             { RUN(verifier_leak_ptr); }

void test_verifier_linked_scalars(void)       { RUN(verifier_linked_scalars); }

void test_verifier_loops1(void)               { RUN(verifier_loops1); }

void test_verifier_lwt(void)                  { RUN(verifier_lwt); }

void test_verifier_map_in_map(void)           { RUN(verifier_map_in_map); }

tools/testing/selftests/bpf/progs/verifier_linked_scalars.c

0 → 100644
+34 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include "bpf_misc.h"



SEC("socket")

__description("scalars: find linked scalars")

__failure

__msg("math between fp pointer and 2147483647 is not allowed")

__naked void scalars(void)

{

	asm volatile ("				\

	r0 = 0;					\

	r1 = 0x80000001 ll;			\

	r1 /= 1;				\

	r2 = r1;				\

	r4 = r1;				\

	w2 += 0x7FFFFFFF;			\

	w4 += 0;				\

	if r2 == 0 goto l1;			\

	exit;					\

l1:						\

	r4 >>= 63;				\

	r3 = 1;					\

	r3 -= r4;				\

	r3 *= 0x7FFFFFFF;			\

	r3 += r10;				\

	*(u8*)(r3 - 1) = r0;			\

	exit;					\

"	::: __clobber_all);

}



char _license[] SEC("license") = "GPL";