// 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";