iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

selftests/bpf: Add a selftest for checking subreg equality

Browse Source 
Add a selftest to ensure subreg equality if source register
upper 32bit is 0. Without previous patch, the test will
fail verification.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230417222139.360607-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song 2023-04-17 15:21:39 -07:00 committed by Alexei Starovoitov
parent 3be49f7955
commit 49859de997
2 changed files with 60 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tools/testing/selftests/bpf/prog_tests/verifier.c
View File

@ -31,6 +31,7 @@
#include "verifier_meta_access.skel.h"
#include "verifier_raw_stack.skel.h"
#include "verifier_raw_tp_writable.skel.h"
#include "verifier_reg_equal.skel.h"
#include "verifier_ringbuf.skel.h"
#include "verifier_spill_fill.skel.h"
#include "verifier_stack_ptr.skel.h"
@ -95,6 +96,7 @@ void test_verifier_masking(void) { RUN(verifier_masking); }
void test_verifier_meta_access(void) { RUN(verifier_meta_access); }
void test_verifier_raw_stack(void) { RUN(verifier_raw_stack); }
void test_verifier_raw_tp_writable(void) { RUN(verifier_raw_tp_writable); }
void test_verifier_reg_equal(void) { RUN(verifier_reg_equal); }
void test_verifier_ringbuf(void) { RUN(verifier_ringbuf); }
void test_verifier_spill_fill(void) { RUN(verifier_spill_fill); }
void test_verifier_stack_ptr(void) { RUN(verifier_stack_ptr); }

58
tools/testing/selftests/bpf/progs/verifier_reg_equal.c Normal file
View File

@ -0,0 +1,58 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
SEC("socket")
__description("check w reg equal if r reg upper32 bits 0")
__success
__naked void subreg_equality_1(void)
{
asm volatile (" \
call %[bpf_ktime_get_ns]; \
*(u64 *)(r10 - 8) = r0; \
r2 = *(u32 *)(r10 - 8); \
/* At this point upper 4-bytes of r2 are 0, \
* thus insn w3 = w2 should propagate reg id, \
* and w2 < 9 comparison would also propagate \
* the range for r3. \
*/ \
w3 = w2; \
if w2 < 9 goto l0_%=; \
exit; \
l0_%=: if r3 < 9 goto l1_%=; \
/* r1 read is illegal at this point */ \
r0 -= r1; \
l1_%=: exit; \
" :
: __imm(bpf_ktime_get_ns)
: __clobber_all);
}
SEC("socket")
__description("check w reg not equal if r reg upper32 bits not 0")
__failure __msg("R1 !read_ok")
__naked void subreg_equality_2(void)
{
asm volatile (" \
call %[bpf_ktime_get_ns]; \
r2 = r0; \
/* Upper 4-bytes of r2 may not be 0, thus insn \
* w3 = w2 should not propagate reg id, and \
* w2 < 9 comparison should not propagate \
* the range for r3 either. \
*/ \
w3 = w2; \
if w2 < 9 goto l0_%=; \
exit; \
l0_%=: if r3 < 9 goto l1_%=; \
/* r1 read is illegal at this point */ \
r0 -= r1; \
l1_%=: exit; \
" :
: __imm(bpf_ktime_get_ns)
: __clobber_all);
}
char _license[] SEC("license") = "GPL";