| 1 | // SPDX-License-Identifier: GPL-2.0 |
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| 2 | |
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| 3 | #include <linux/bpf.h> |
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| 4 | #include <bpf/bpf_helpers.h> |
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| 5 | #include "bpf_misc.h" |
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| 6 | |
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| 7 | SEC("socket" ) |
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| 8 | __description("check w reg equal if r reg upper32 bits 0" ) |
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| 9 | __success |
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| 10 | __naked void subreg_equality_1(void) |
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| 11 | { |
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| 12 | asm volatile (" \ |
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| 13 | call %[bpf_ktime_get_ns]; \ |
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| 14 | *(u64 *)(r10 - 8) = r0; \ |
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| 15 | r2 = *(u32 *)(r10 - 8); \ |
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| 16 | /* At this point upper 4-bytes of r2 are 0, \ |
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| 17 | * thus insn w3 = w2 should propagate reg id, \ |
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| 18 | * and w2 < 9 comparison would also propagate \ |
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| 19 | * the range for r3. \ |
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| 20 | */ \ |
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| 21 | w3 = w2; \ |
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| 22 | if w2 < 9 goto l0_%=; \ |
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| 23 | exit; \ |
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| 24 | l0_%=: if r3 < 9 goto l1_%=; \ |
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| 25 | /* r1 read is illegal at this point */ \ |
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| 26 | r0 -= r1; \ |
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| 27 | l1_%=: exit; \ |
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| 28 | " : |
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| 29 | : __imm(bpf_ktime_get_ns) |
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| 30 | : __clobber_all); |
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| 31 | } |
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| 32 | |
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| 33 | SEC("socket" ) |
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| 34 | __description("check w reg not equal if r reg upper32 bits not 0" ) |
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| 35 | __failure __msg("R1 !read_ok" ) |
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| 36 | __naked void subreg_equality_2(void) |
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| 37 | { |
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| 38 | asm volatile (" \ |
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| 39 | call %[bpf_ktime_get_ns]; \ |
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| 40 | r2 = r0; \ |
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| 41 | /* Upper 4-bytes of r2 may not be 0, thus insn \ |
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| 42 | * w3 = w2 should not propagate reg id, and \ |
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| 43 | * w2 < 9 comparison should not propagate \ |
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| 44 | * the range for r3 either. \ |
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| 45 | */ \ |
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| 46 | w3 = w2; \ |
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| 47 | if w2 < 9 goto l0_%=; \ |
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| 48 | exit; \ |
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| 49 | l0_%=: if r3 < 9 goto l1_%=; \ |
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| 50 | /* r1 read is illegal at this point */ \ |
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| 51 | r0 -= r1; \ |
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| 52 | l1_%=: exit; \ |
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| 53 | " : |
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| 54 | : __imm(bpf_ktime_get_ns) |
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| 55 | : __clobber_all); |
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| 56 | } |
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| 57 | |
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| 58 | char _license[] SEC("license" ) = "GPL" ; |
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| 59 | |
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