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selftests/bpf: Add test case for delta propagation

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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: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20241016134913.32249-3-daniel@iogearbox.net
This commit is contained in:
Daniel Borkmann 2024-10-16 15:49:13 +02:00 committed by Andrii Nakryiko
parent 3e9e708757
commit db123e4230
2 changed files with 36 additions and 0 deletions
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2
tools/testing/selftests/bpf/prog_tests/verifier.c
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@ -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); }

34
tools/testing/selftests/bpf/progs/verifier_linked_scalars.c Normal file
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@ -0,0 +1,34 @@
// 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";