Commit 79741b3b authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller

bpf: refactor fixup_bpf_calls()

reduce indent and make it iterate over instructions similar to
convert_ctx_accesses(). Also convert hard BUG_ON into soft verifier error.
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e245c5c6
......@@ -3233,29 +3233,21 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
return 0;
}
/* fixup insn->imm field of bpf_call instructions:
* if (insn->imm == BPF_FUNC_map_lookup_elem)
* insn->imm = bpf_map_lookup_elem - __bpf_call_base;
* else if (insn->imm == BPF_FUNC_map_update_elem)
* insn->imm = bpf_map_update_elem - __bpf_call_base;
* else ...
/* fixup insn->imm field of bpf_call instructions
*
* this function is called after eBPF program passed verification
*/
static void fixup_bpf_calls(struct bpf_prog *prog)
static int fixup_bpf_calls(struct bpf_verifier_env *env)
{
struct bpf_prog *prog = env->prog;
struct bpf_insn *insn = prog->insnsi;
const struct bpf_func_proto *fn;
const int insn_cnt = prog->len;
int i;
for (i = 0; i < prog->len; i++) {
struct bpf_insn *insn = &prog->insnsi[i];
if (insn->code == (BPF_JMP | BPF_CALL)) {
/* we reach here when program has bpf_call instructions
* and it passed bpf_check(), means that
* ops->get_func_proto must have been supplied, check it
*/
BUG_ON(!prog->aux->ops->get_func_proto);
for (i = 0; i < insn_cnt; i++, insn++) {
if (insn->code != (BPF_JMP | BPF_CALL))
continue;
if (insn->imm == BPF_FUNC_get_route_realm)
prog->dst_needed = 1;
......@@ -3264,12 +3256,10 @@ static void fixup_bpf_calls(struct bpf_prog *prog)
if (insn->imm == BPF_FUNC_xdp_adjust_head)
prog->xdp_adjust_head = 1;
if (insn->imm == BPF_FUNC_tail_call) {
/* mark bpf_tail_call as different opcode
* to avoid conditional branch in
* interpeter for every normal call
* and to prevent accidental JITing by
* JIT compiler that doesn't support
* bpf_tail_call yet
/* mark bpf_tail_call as different opcode to avoid
* conditional branch in the interpeter for every normal
* call and to prevent accidental JITing by JIT compiler
* that doesn't support bpf_tail_call yet
*/
insn->imm = 0;
insn->code |= BPF_X;
......@@ -3280,12 +3270,16 @@ static void fixup_bpf_calls(struct bpf_prog *prog)
/* all functions that have prototype and verifier allowed
* programs to call them, must be real in-kernel functions
*/
BUG_ON(!fn->func);
insn->imm = fn->func - __bpf_call_base;
if (!fn->func) {
verbose("kernel subsystem misconfigured func %s#%d\n",
func_id_name(insn->imm), insn->imm);
return -EFAULT;
}
insn->imm = fn->func - __bpf_call_base;
}
}
return 0;
}
static void free_states(struct bpf_verifier_env *env)
{
......@@ -3383,7 +3377,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
ret = convert_ctx_accesses(env);
if (ret == 0)
fixup_bpf_calls(env->prog);
ret = fixup_bpf_calls(env);
if (log_level && log_len >= log_size - 1) {
BUG_ON(log_len >= log_size);
......
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