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bpf/verifier: rework value tracking

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Unifies adjusted and unadjusted register value types (e.g. FRAME_POINTER is
 now just a PTR_TO_STACK with zero offset).
Tracks value alignment by means of tracking known & unknown bits.  This
 also replaces the 'reg->imm' (leading zero bits) calculations for (what
 were) UNKNOWN_VALUEs.
If pointer leaks are allowed, and adjust_ptr_min_max_vals returns -EACCES,
 treat the pointer as an unknown scalar and try again, because we might be
 able to conclude something about the result (e.g. pointer & 0x40 is either
 0 or 0x40).
Verifier hooks in the netronome/nfp driver were changed to match the new
 data structures.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Edward Cree
2017-08-07 15:26:19 +01:00
committed by David S. Miller
parent e1cb90f2b8
commit f1174f77b5
7 changed files with 1277 additions and 864 deletions
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24
drivers/net/ethernet/netronome/nfp/bpf/verifier.c
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@@ -79,28 +79,32 @@ nfp_bpf_check_exit(struct nfp_prog *nfp_prog,
const struct bpf_verifier_env *env)
{
const struct bpf_reg_state *reg0 = &env->cur_state.regs[0];
u64 imm;
if (nfp_prog->act == NN_ACT_XDP)
return 0;
if (reg0->type != CONST_IMM) {
pr_info("unsupported exit state: %d, imm: %llx\n",
reg0->type, reg0->imm);
if (!(reg0->type == SCALAR_VALUE && tnum_is_const(reg0->var_off))) {
char tn_buf[48];
tnum_strn(tn_buf, sizeof(tn_buf), reg0->var_off);
pr_info("unsupported exit state: %d, var_off: %s\n",
reg0->type, tn_buf);
return -EINVAL;
}
if (nfp_prog->act != NN_ACT_DIRECT &&
reg0->imm != 0 && (reg0->imm & ~0U) != ~0U) {
imm = reg0->var_off.value;
if (nfp_prog->act != NN_ACT_DIRECT && imm != 0 && (imm & ~0U) != ~0U) {
pr_info("unsupported exit state: %d, imm: %llx\n",
reg0->type, reg0->imm);
reg0->type, imm);
return -EINVAL;
}
if (nfp_prog->act == NN_ACT_DIRECT && reg0->imm <= TC_ACT_REDIRECT &&
reg0->imm != TC_ACT_SHOT && reg0->imm != TC_ACT_STOLEN &&
reg0->imm != TC_ACT_QUEUED) {
if (nfp_prog->act == NN_ACT_DIRECT && imm <= TC_ACT_REDIRECT &&
imm != TC_ACT_SHOT && imm != TC_ACT_STOLEN &&
imm != TC_ACT_QUEUED) {
pr_info("unsupported exit state: %d, imm: %llx\n",
reg0->type, reg0->imm);
reg0->type, imm);
return -EINVAL;
}