diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 3a85c3ff4a4358c3dde96548982233c1ee7a6be9..71511690e4c16014c388a84d064431fce71c874f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -13814,7 +13814,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } else { /* all other ALU ops: and, sub, xor, add, ... */ if (BPF_SRC(insn->code) == BPF_X) { - if (insn->imm != 0 || insn->off > 1 || + if (insn->imm != 0 || (insn->off != 0 && insn->off != 1) || (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) { verbose(env, "BPF_ALU uses reserved fields\n"); return -EINVAL; @@ -13824,7 +13824,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) if (err) return err; } else { - if (insn->src_reg != BPF_REG_0 || insn->off > 1 || + if (insn->src_reg != BPF_REG_0 || (insn->off != 0 && insn->off != 1) || (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) { verbose(env, "BPF_ALU uses reserved fields\n"); return -EINVAL; diff --git a/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c b/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c index 71814a7532160638b1f345d42fcfcef4c62f8182..2cb659d25978c20529c50ede947353a98ac33ddd 100644 --- a/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c +++ b/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c @@ -3,6 +3,7 @@ #include #include +#include "../../../include/linux/filter.h" #include "bpf_misc.h" #define MAX_ENTRIES 11 @@ -146,4 +147,32 @@ l0_%=: exit; \ : __clobber_all); } +#define DEFINE_BAD_OFFSET_TEST(name, op, off, imm) \ + SEC("socket") \ + __failure __msg("BPF_ALU uses reserved fields") \ + __naked void name(void) \ + { \ + asm volatile( \ + "r0 = 1;" \ + ".8byte %[insn];" \ + "r0 = 0;" \ + "exit;" \ + : \ + : __imm_insn(insn, BPF_RAW_INSN((op), 0, 0, (off), (imm))) \ + : __clobber_all); \ + } + +/* + * Offset fields of 0 and 1 are legal for BPF_{DIV,MOD} instructions. + * Offset fields of 0 are legal for the rest of ALU instructions. + * Test that error is reported for illegal offsets, assuming that tests + * for legal offsets exist. + */ +DEFINE_BAD_OFFSET_TEST(bad_offset_divx, BPF_ALU64 | BPF_DIV | BPF_X, -1, 0) +DEFINE_BAD_OFFSET_TEST(bad_offset_modk, BPF_ALU64 | BPF_MOD | BPF_K, -1, 1) +DEFINE_BAD_OFFSET_TEST(bad_offset_addx, BPF_ALU64 | BPF_ADD | BPF_X, -1, 0) +DEFINE_BAD_OFFSET_TEST(bad_offset_divx2, BPF_ALU64 | BPF_DIV | BPF_X, 2, 0) +DEFINE_BAD_OFFSET_TEST(bad_offset_modk2, BPF_ALU64 | BPF_MOD | BPF_K, 2, 1) +DEFINE_BAD_OFFSET_TEST(bad_offset_addx2, BPF_ALU64 | BPF_ADD | BPF_X, 1, 0) + char _license[] SEC("license") = "GPL";