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