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| author |   Alexei Starovoitov <ast@kernel.org> | 2018-11-10 22:29:59 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2018-11-10 22:30:00 -0800 |
| commit | 407be8d03e20d70d15cd8c21591202a591e3c2b2 (patch) | |
| tree | 909ae9f0eb94d01c31e640c7a4a95f7ff400d959 /kernel | |
| parent | Merge branch 'bpftool-flow-dissector' (diff) | |
| parent | selftests/bpf: Test narrow loads with off > 0 for bpf_sock_addr (diff) | |
Merge branch 'narrow-loads'
Andrey Ignatov says:
====================
This patch set adds support for narrow loads with offset > 0 to BPF
verifier.
Patch 1 provides more details and is the main patch in the set.
Patches 2 and 3 add new test cases to test_verifier and test_sock_addr
selftests.
v1->v2:
- fix -Wdeclaration-after-statement warning.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8d0977980cfa..b5222aa61d54 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5718,10 +5718,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) int i, cnt, size, ctx_field_size, delta = 0; const int insn_cnt = env->prog->len; struct bpf_insn insn_buf[16], *insn; + u32 target_size, size_default, off; struct bpf_prog *new_prog; enum bpf_access_type type; bool is_narrower_load; - u32 target_size; if (ops->gen_prologue || env->seen_direct_write) { if (!ops->gen_prologue) { @@ -5814,9 +5814,9 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) * we will apply proper mask to the result. */ is_narrower_load = size < ctx_field_size; + size_default = bpf_ctx_off_adjust_machine(ctx_field_size); + off = insn->off; if (is_narrower_load) { - u32 size_default = bpf_ctx_off_adjust_machine(ctx_field_size); - u32 off = insn->off; u8 size_code; if (type == BPF_WRITE) { @@ -5844,12 +5844,23 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) } if (is_narrower_load && size < target_size) { - if (ctx_field_size <= 4) + u8 shift = (off & (size_default - 1)) * 8; + + if (ctx_field_size <= 4) { + if (shift) + insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH, + insn->dst_reg, + shift); insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg, (1 << size * 8) - 1); - else + } else { + if (shift) + insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH, + insn->dst_reg, + shift); insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg, (1 << size * 8) - 1); + } } new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); |