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kernel
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linux
selftests/bpf: Add a selftest for checking subreg equality
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>
authored by
Yonghong Song
and committed by
Alexei Starovoitov
49859de9
3be49f79
+60
+2
tools/testing/selftests/bpf/prog_tests/verifier.c
+2
tools/testing/selftests/bpf/prog_tests/verifier.c
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#include "verifier_meta_access.skel.h"
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#include "verifier_raw_stack.skel.h"
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#include "verifier_raw_tp_writable.skel.h"
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#include "verifier_reg_equal.skel.h"
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#include "verifier_ringbuf.skel.h"
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#include "verifier_spill_fill.skel.h"
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#include "verifier_stack_ptr.skel.h"
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void test_verifier_meta_access(void) { RUN(verifier_meta_access); }
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void test_verifier_raw_stack(void) { RUN(verifier_raw_stack); }
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void test_verifier_raw_tp_writable(void) { RUN(verifier_raw_tp_writable); }
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void test_verifier_reg_equal(void) { RUN(verifier_reg_equal); }
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void test_verifier_ringbuf(void) { RUN(verifier_ringbuf); }
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void test_verifier_spill_fill(void) { RUN(verifier_spill_fill); }
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void test_verifier_stack_ptr(void) { RUN(verifier_stack_ptr); }
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tools/testing/selftests/bpf/progs/verifier_reg_equal.c
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tools/testing/selftests/bpf/progs/verifier_reg_equal.c
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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SEC("socket")
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__description("check w reg equal if r reg upper32 bits 0")
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__success
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__naked void subreg_equality_1(void)
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{
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asm volatile (" \
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call %[bpf_ktime_get_ns]; \
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*(u64 *)(r10 - 8) = r0; \
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r2 = *(u32 *)(r10 - 8); \
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/* At this point upper 4-bytes of r2 are 0, \
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* thus insn w3 = w2 should propagate reg id, \
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* and w2 < 9 comparison would also propagate \
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* the range for r3. \
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*/ \
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w3 = w2; \
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if w2 < 9 goto l0_%=; \
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exit; \
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l0_%=: if r3 < 9 goto l1_%=; \
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/* r1 read is illegal at this point */ \
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r0 -= r1; \
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l1_%=: exit; \
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" :
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: __imm(bpf_ktime_get_ns)
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: __clobber_all);
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}
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SEC("socket")
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__description("check w reg not equal if r reg upper32 bits not 0")
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__failure __msg("R1 !read_ok")
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__naked void subreg_equality_2(void)
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{
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asm volatile (" \
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call %[bpf_ktime_get_ns]; \
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r2 = r0; \
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/* Upper 4-bytes of r2 may not be 0, thus insn \
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* w3 = w2 should not propagate reg id, and \
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* w2 < 9 comparison should not propagate \
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* the range for r3 either. \
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*/ \
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w3 = w2; \
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if w2 < 9 goto l0_%=; \
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exit; \
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l0_%=: if r3 < 9 goto l1_%=; \
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/* r1 read is illegal at this point */ \
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r0 -= r1; \
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l1_%=: exit; \
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" :
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: __imm(bpf_ktime_get_ns)
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: __clobber_all);
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}
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char _license[] SEC("license") = "GPL";