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bpf: change logging calls from verbose() to bpf_log() and use log poi…
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…nter

In preparation for moving code around, change a bunch of references to
env->log (and the verbose() logging helper) to use bpf_log() and a direct
pointer to struct bpf_verifier_log. While we're touching the function
signature, mark the 'prog' argument to bpf_check_type_match() as const.

Also enhance the bpf_verifier_log_needed() check to handle NULL pointers
for the log struct so we can re-use the code with logging disabled.

Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Toke Høiland-Jørgensen authored and Alexei Starovoitov committed Sep 29, 2020
1 parent 1af9270 commit efc6815
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Showing 4 changed files with 32 additions and 31 deletions.
2 changes: 1 addition & 1 deletion include/linux/bpf.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1420,7 +1420,7 @@ int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog,
struct bpf_reg_state *regs);
int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
struct bpf_reg_state *reg);
int btf_check_type_match(struct bpf_verifier_env *env, struct bpf_prog *prog,
int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
struct btf *btf, const struct btf_type *t);

struct bpf_prog *bpf_prog_by_id(u32 id);
Expand Down
5 changes: 3 additions & 2 deletions include/linux/bpf_verifier.h
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Original file line number Diff line number Diff line change
Expand Up @@ -347,8 +347,9 @@ static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log)

static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
{
return (log->level && log->ubuf && !bpf_verifier_log_full(log)) ||
log->level == BPF_LOG_KERNEL;
return log &&
((log->level && log->ubuf && !bpf_verifier_log_full(log)) ||
log->level == BPF_LOG_KERNEL);
}

#define BPF_MAX_SUBPROGS 256
Expand Down
6 changes: 3 additions & 3 deletions kernel/bpf/btf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4388,15 +4388,15 @@ static int btf_check_func_type_match(struct bpf_verifier_log *log,
}

/* Compare BTFs of given program with BTF of target program */
int btf_check_type_match(struct bpf_verifier_env *env, struct bpf_prog *prog,
int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
struct btf *btf2, const struct btf_type *t2)
{
struct btf *btf1 = prog->aux->btf;
const struct btf_type *t1;
u32 btf_id = 0;

if (!prog->aux->func_info) {
bpf_log(&env->log, "Program extension requires BTF\n");
bpf_log(log, "Program extension requires BTF\n");
return -EINVAL;
}

Expand All @@ -4408,7 +4408,7 @@ int btf_check_type_match(struct bpf_verifier_env *env, struct bpf_prog *prog,
if (!t1 || !btf_type_is_func(t1))
return -EFAULT;

return btf_check_func_type_match(&env->log, btf1, t1, btf2, t2);
return btf_check_func_type_match(log, btf1, t1, btf2, t2);
}

/* Compare BTF of a function with given bpf_reg_state.
Expand Down
50 changes: 25 additions & 25 deletions kernel/bpf/verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11249,6 +11249,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
struct bpf_prog *prog = env->prog;
bool prog_extension = prog->type == BPF_PROG_TYPE_EXT;
struct bpf_prog *tgt_prog = prog->aux->linked_prog;
struct bpf_verifier_log *log = &env->log;
u32 btf_id = prog->aux->attach_btf_id;
const char prefix[] = "btf_trace_";
struct btf_func_model fmodel;
Expand Down Expand Up @@ -11276,23 +11277,23 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
return 0;

if (!btf_id) {
verbose(env, "Tracing programs must provide btf_id\n");
bpf_log(log, "Tracing programs must provide btf_id\n");
return -EINVAL;
}
btf = bpf_prog_get_target_btf(prog);
if (!btf) {
verbose(env,
bpf_log(log,
"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
return -EINVAL;
}
t = btf_type_by_id(btf, btf_id);
if (!t) {
verbose(env, "attach_btf_id %u is invalid\n", btf_id);
bpf_log(log, "attach_btf_id %u is invalid\n", btf_id);
return -EINVAL;
}
tname = btf_name_by_offset(btf, t->name_off);
if (!tname) {
verbose(env, "attach_btf_id %u doesn't have a name\n", btf_id);
bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id);
return -EINVAL;
}
if (tgt_prog) {
Expand All @@ -11304,34 +11305,34 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
break;
}
if (subprog == -1) {
verbose(env, "Subprog %s doesn't exist\n", tname);
bpf_log(log, "Subprog %s doesn't exist\n", tname);
return -EINVAL;
}
conservative = aux->func_info_aux[subprog].unreliable;
if (prog_extension) {
if (conservative) {
verbose(env,
bpf_log(log,
"Cannot replace static functions\n");
return -EINVAL;
}
if (!prog->jit_requested) {
verbose(env,
bpf_log(log,
"Extension programs should be JITed\n");
return -EINVAL;
}
env->ops = bpf_verifier_ops[tgt_prog->type];
prog->expected_attach_type = tgt_prog->expected_attach_type;
}
if (!tgt_prog->jited) {
verbose(env, "Can attach to only JITed progs\n");
bpf_log(log, "Can attach to only JITed progs\n");
return -EINVAL;
}
if (tgt_prog->type == prog->type) {
/* Cannot fentry/fexit another fentry/fexit program.
* Cannot attach program extension to another extension.
* It's ok to attach fentry/fexit to extension program.
*/
verbose(env, "Cannot recursively attach\n");
bpf_log(log, "Cannot recursively attach\n");
return -EINVAL;
}
if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
Expand All @@ -11353,13 +11354,13 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
* reasonable stack size. Hence extending fentry is not
* allowed.
*/
verbose(env, "Cannot extend fentry/fexit\n");
bpf_log(log, "Cannot extend fentry/fexit\n");
return -EINVAL;
}
key = ((u64)aux->id) << 32 | btf_id;
} else {
if (prog_extension) {
verbose(env, "Cannot replace kernel functions\n");
bpf_log(log, "Cannot replace kernel functions\n");
return -EINVAL;
}
key = btf_id;
Expand All @@ -11368,17 +11369,17 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
switch (prog->expected_attach_type) {
case BPF_TRACE_RAW_TP:
if (tgt_prog) {
verbose(env,
bpf_log(log,
"Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
return -EINVAL;
}
if (!btf_type_is_typedef(t)) {
verbose(env, "attach_btf_id %u is not a typedef\n",
bpf_log(log, "attach_btf_id %u is not a typedef\n",
btf_id);
return -EINVAL;
}
if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
verbose(env, "attach_btf_id %u points to wrong type name %s\n",
bpf_log(log, "attach_btf_id %u points to wrong type name %s\n",
btf_id, tname);
return -EINVAL;
}
Expand All @@ -11401,7 +11402,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
return 0;
case BPF_TRACE_ITER:
if (!btf_type_is_func(t)) {
verbose(env, "attach_btf_id %u is not a function\n",
bpf_log(log, "attach_btf_id %u is not a function\n",
btf_id);
return -EINVAL;
}
Expand All @@ -11412,8 +11413,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
prog->aux->attach_func_proto = t;
if (!bpf_iter_prog_supported(prog))
return -EINVAL;
ret = btf_distill_func_proto(&env->log, btf, t,
tname, &fmodel);
ret = btf_distill_func_proto(log, btf, t, tname, &fmodel);
return ret;
default:
if (!prog_extension)
Expand All @@ -11425,18 +11425,18 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
case BPF_TRACE_FEXIT:
prog->aux->attach_func_name = tname;
if (prog->type == BPF_PROG_TYPE_LSM) {
ret = bpf_lsm_verify_prog(&env->log, prog);
ret = bpf_lsm_verify_prog(log, prog);
if (ret < 0)
return ret;
}

if (!btf_type_is_func(t)) {
verbose(env, "attach_btf_id %u is not a function\n",
bpf_log(log, "attach_btf_id %u is not a function\n",
btf_id);
return -EINVAL;
}
if (prog_extension &&
btf_check_type_match(env, prog, btf, t))
btf_check_type_match(log, prog, btf, t))
return -EINVAL;
t = btf_type_by_id(btf, t->type);
if (!btf_type_is_func_proto(t))
Expand All @@ -11455,7 +11455,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
prog->aux->attach_func_proto = NULL;
t = NULL;
}
ret = btf_distill_func_proto(&env->log, btf, t,
ret = btf_distill_func_proto(log, btf, t,
tname, &tr->func.model);
if (ret < 0)
goto out;
Expand All @@ -11467,7 +11467,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
} else {
addr = kallsyms_lookup_name(tname);
if (!addr) {
verbose(env,
bpf_log(log,
"The address of function %s cannot be found\n",
tname);
ret = -ENOENT;
Expand Down Expand Up @@ -11497,17 +11497,17 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
break;
}
if (ret)
verbose(env, "%s is not sleepable\n",
bpf_log(log, "%s is not sleepable\n",
prog->aux->attach_func_name);
} else if (prog->expected_attach_type == BPF_MODIFY_RETURN) {
if (tgt_prog) {
verbose(env, "can't modify return codes of BPF programs\n");
bpf_log(log, "can't modify return codes of BPF programs\n");
ret = -EINVAL;
goto out;
}
ret = check_attach_modify_return(prog, addr);
if (ret)
verbose(env, "%s() is not modifiable\n",
bpf_log(log, "%s() is not modifiable\n",
prog->aux->attach_func_name);
}
if (ret)
Expand Down

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