2018-03-23 10:42:39

by Jiri Olsa

[permalink] [raw]
Subject: [PATCH 0/2] bpf: Change print_bpf_insn interface

hi,
this patchset removes struct bpf_verifier_env argument
from print_bpf_insn function (patch 1) and changes user
space bpftool user to use it that way (patch 2).

thanks,
jirka

---
Jiri Olsa (2):
bpf: Remove struct bpf_verifier_env argument from print_bpf_insn
bpftool: Adjust to new print_bpf_insn interface

kernel/bpf/disasm.c | 52 ++++++++++++++++++++++++++--------------------------
kernel/bpf/disasm.h | 5 +----
kernel/bpf/verifier.c | 44 +++++++++++++++++++++++++++-----------------
tools/bpf/bpftool/xlated_dumper.c | 12 ++++++------
4 files changed, 60 insertions(+), 53 deletions(-)


2018-03-23 10:42:57

by Jiri Olsa

[permalink] [raw]
Subject: [PATCH 2/2] bpftool: Adjust to new print_bpf_insn interface

Change bpftool to skip the removed struct bpf_verifier_env
argument in print_bpf_insn. It was passed as NULL anyway.

No functional change intended.

Signed-off-by: Jiri Olsa <[email protected]>
---
tools/bpf/bpftool/xlated_dumper.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 20da835e9e38..7a3173b76c16 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -114,7 +114,7 @@ static struct kernel_sym *kernel_syms_search(struct dump_data *dd,
sizeof(*dd->sym_mapping), kernel_syms_cmp) : NULL;
}

-static void print_insn(struct bpf_verifier_env *env, const char *fmt, ...)
+static void print_insn(void *private_data, const char *fmt, ...)
{
va_list args;

@@ -124,7 +124,7 @@ static void print_insn(struct bpf_verifier_env *env, const char *fmt, ...)
}

static void
-print_insn_for_graph(struct bpf_verifier_env *env, const char *fmt, ...)
+print_insn_for_graph(void *private_data, const char *fmt, ...)
{
char buf[64], *p;
va_list args;
@@ -154,7 +154,7 @@ print_insn_for_graph(struct bpf_verifier_env *env, const char *fmt, ...)
printf("%s", buf);
}

-static void print_insn_json(struct bpf_verifier_env *env, const char *fmt, ...)
+static void print_insn_json(void *private_data, const char *fmt, ...)
{
unsigned int l = strlen(fmt);
char chomped_fmt[l];
@@ -248,7 +248,7 @@ void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len,

jsonw_start_object(json_wtr);
jsonw_name(json_wtr, "disasm");
- print_bpf_insn(&cbs, NULL, insn + i, true);
+ print_bpf_insn(&cbs, insn + i, true);

if (opcodes) {
jsonw_name(json_wtr, "opcodes");
@@ -302,7 +302,7 @@ void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len,
double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);

printf("% 4d: ", i);
- print_bpf_insn(&cbs, NULL, insn + i, true);
+ print_bpf_insn(&cbs, insn + i, true);

if (opcodes) {
printf(" ");
@@ -331,7 +331,7 @@ void dump_xlated_for_graph(struct dump_data *dd, void *buf_start, void *buf_end,

for (; cur <= insn_end; cur++) {
printf("% 4d: ", (int)(cur - insn_start + start_idx));
- print_bpf_insn(&cbs, NULL, cur, true);
+ print_bpf_insn(&cbs, cur, true);
if (cur != insn_end)
printf(" | ");
}
--
2.13.6


2018-03-23 10:43:20

by Jiri Olsa

[permalink] [raw]
Subject: [PATCH 1/2] bpf: Remove struct bpf_verifier_env argument from print_bpf_insn

We use print_bpf_insn in user space (bpftool and soon perf),
so it'd be nice to keep it generic and strip it off the kernel
struct bpf_verifier_env argument.

This argument can be safely removed, because its users can
use the struct bpf_insn_cbs::private_data to pass it.

By changing the argument type we can no longer have clean
'verbose' alias to 'bpf_verifier_log_write' in verifier.c.
Instead we're adding the 'verbose' cb_print callback and
removing the alias.

This way we have new cb_print callback in place, and all
the 'verbose(env, ...) calls in verifier.c will cleanly
cast to 'verbose(void *, ...)' so no other change is
needed.

Signed-off-by: Jiri Olsa <[email protected]>
---
kernel/bpf/disasm.c | 52 +++++++++++++++++++++++++--------------------------
kernel/bpf/disasm.h | 5 +----
kernel/bpf/verifier.c | 44 ++++++++++++++++++++++++++-----------------
3 files changed, 54 insertions(+), 47 deletions(-)

diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c
index 8740406df2cd..d6b76377cb6e 100644
--- a/kernel/bpf/disasm.c
+++ b/kernel/bpf/disasm.c
@@ -113,16 +113,16 @@ static const char *const bpf_jmp_string[16] = {
};

static void print_bpf_end_insn(bpf_insn_print_t verbose,
- struct bpf_verifier_env *env,
+ void *private_data,
const struct bpf_insn *insn)
{
- verbose(env, "(%02x) r%d = %s%d r%d\n", insn->code, insn->dst_reg,
+ verbose(private_data, "(%02x) r%d = %s%d r%d\n",
+ insn->code, insn->dst_reg,
BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
insn->imm, insn->dst_reg);
}

void print_bpf_insn(const struct bpf_insn_cbs *cbs,
- struct bpf_verifier_env *env,
const struct bpf_insn *insn,
bool allow_ptr_leaks)
{
@@ -132,23 +132,23 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
if (class == BPF_ALU || class == BPF_ALU64) {
if (BPF_OP(insn->code) == BPF_END) {
if (class == BPF_ALU64)
- verbose(env, "BUG_alu64_%02x\n", insn->code);
+ verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
else
- print_bpf_end_insn(verbose, env, insn);
+ print_bpf_end_insn(verbose, cbs->private_data, insn);
} else if (BPF_OP(insn->code) == BPF_NEG) {
- verbose(env, "(%02x) r%d = %s-r%d\n",
+ verbose(cbs->private_data, "(%02x) r%d = %s-r%d\n",
insn->code, insn->dst_reg,
class == BPF_ALU ? "(u32) " : "",
insn->dst_reg);
} else if (BPF_SRC(insn->code) == BPF_X) {
- verbose(env, "(%02x) %sr%d %s %sr%d\n",
+ verbose(cbs->private_data, "(%02x) %sr%d %s %sr%d\n",
insn->code, class == BPF_ALU ? "(u32) " : "",
insn->dst_reg,
bpf_alu_string[BPF_OP(insn->code) >> 4],
class == BPF_ALU ? "(u32) " : "",
insn->src_reg);
} else {
- verbose(env, "(%02x) %sr%d %s %s%d\n",
+ verbose(cbs->private_data, "(%02x) %sr%d %s %s%d\n",
insn->code, class == BPF_ALU ? "(u32) " : "",
insn->dst_reg,
bpf_alu_string[BPF_OP(insn->code) >> 4],
@@ -157,46 +157,46 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
}
} else if (class == BPF_STX) {
if (BPF_MODE(insn->code) == BPF_MEM)
- verbose(env, "(%02x) *(%s *)(r%d %+d) = r%d\n",
+ verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
insn->code,
bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
insn->dst_reg,
insn->off, insn->src_reg);
else if (BPF_MODE(insn->code) == BPF_XADD)
- verbose(env, "(%02x) lock *(%s *)(r%d %+d) += r%d\n",
+ verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) += r%d\n",
insn->code,
bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
insn->dst_reg, insn->off,
insn->src_reg);
else
- verbose(env, "BUG_%02x\n", insn->code);
+ verbose(cbs->private_data, "BUG_%02x\n", insn->code);
} else if (class == BPF_ST) {
if (BPF_MODE(insn->code) != BPF_MEM) {
- verbose(env, "BUG_st_%02x\n", insn->code);
+ verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
return;
}
- verbose(env, "(%02x) *(%s *)(r%d %+d) = %d\n",
+ verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
insn->code,
bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
insn->dst_reg,
insn->off, insn->imm);
} else if (class == BPF_LDX) {
if (BPF_MODE(insn->code) != BPF_MEM) {
- verbose(env, "BUG_ldx_%02x\n", insn->code);
+ verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
return;
}
- verbose(env, "(%02x) r%d = *(%s *)(r%d %+d)\n",
+ verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
insn->code, insn->dst_reg,
bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
insn->src_reg, insn->off);
} else if (class == BPF_LD) {
if (BPF_MODE(insn->code) == BPF_ABS) {
- verbose(env, "(%02x) r0 = *(%s *)skb[%d]\n",
+ verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
insn->code,
bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
insn->imm);
} else if (BPF_MODE(insn->code) == BPF_IND) {
- verbose(env, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
+ verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
insn->code,
bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
insn->src_reg, insn->imm);
@@ -212,12 +212,12 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
if (map_ptr && !allow_ptr_leaks)
imm = 0;

- verbose(env, "(%02x) r%d = %s\n",
+ verbose(cbs->private_data, "(%02x) r%d = %s\n",
insn->code, insn->dst_reg,
__func_imm_name(cbs, insn, imm,
tmp, sizeof(tmp)));
} else {
- verbose(env, "BUG_ld_%02x\n", insn->code);
+ verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
return;
}
} else if (class == BPF_JMP) {
@@ -227,35 +227,35 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
char tmp[64];

if (insn->src_reg == BPF_PSEUDO_CALL) {
- verbose(env, "(%02x) call pc%s\n",
+ verbose(cbs->private_data, "(%02x) call pc%s\n",
insn->code,
__func_get_name(cbs, insn,
tmp, sizeof(tmp)));
} else {
strcpy(tmp, "unknown");
- verbose(env, "(%02x) call %s#%d\n", insn->code,
+ verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
__func_get_name(cbs, insn,
tmp, sizeof(tmp)),
insn->imm);
}
} else if (insn->code == (BPF_JMP | BPF_JA)) {
- verbose(env, "(%02x) goto pc%+d\n",
+ verbose(cbs->private_data, "(%02x) goto pc%+d\n",
insn->code, insn->off);
} else if (insn->code == (BPF_JMP | BPF_EXIT)) {
- verbose(env, "(%02x) exit\n", insn->code);
+ verbose(cbs->private_data, "(%02x) exit\n", insn->code);
} else if (BPF_SRC(insn->code) == BPF_X) {
- verbose(env, "(%02x) if r%d %s r%d goto pc%+d\n",
+ verbose(cbs->private_data, "(%02x) if r%d %s r%d goto pc%+d\n",
insn->code, insn->dst_reg,
bpf_jmp_string[BPF_OP(insn->code) >> 4],
insn->src_reg, insn->off);
} else {
- verbose(env, "(%02x) if r%d %s 0x%x goto pc%+d\n",
+ verbose(cbs->private_data, "(%02x) if r%d %s 0x%x goto pc%+d\n",
insn->code, insn->dst_reg,
bpf_jmp_string[BPF_OP(insn->code) >> 4],
insn->imm, insn->off);
}
} else {
- verbose(env, "(%02x) %s\n",
+ verbose(cbs->private_data, "(%02x) %s\n",
insn->code, bpf_class_string[class]);
}
}
diff --git a/kernel/bpf/disasm.h b/kernel/bpf/disasm.h
index 266fe8ee542b..e1324a834a24 100644
--- a/kernel/bpf/disasm.h
+++ b/kernel/bpf/disasm.h
@@ -22,14 +22,12 @@
#include <string.h>
#endif

-struct bpf_verifier_env;
-
extern const char *const bpf_alu_string[16];
extern const char *const bpf_class_string[8];

const char *func_id_name(int id);

-typedef __printf(2, 3) void (*bpf_insn_print_t)(struct bpf_verifier_env *env,
+typedef __printf(2, 3) void (*bpf_insn_print_t)(void *private_data,
const char *, ...);
typedef const char *(*bpf_insn_revmap_call_t)(void *private_data,
const struct bpf_insn *insn);
@@ -45,7 +43,6 @@ struct bpf_insn_cbs {
};

void print_bpf_insn(const struct bpf_insn_cbs *cbs,
- struct bpf_verifier_env *env,
const struct bpf_insn *insn,
bool allow_ptr_leaks);
#endif
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e9f7c20691c1..e93a6e48641b 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -168,23 +168,16 @@ struct bpf_call_arg_meta {

static DEFINE_MUTEX(bpf_verifier_lock);

-/* log_level controls verbosity level of eBPF verifier.
- * bpf_verifier_log_write() is used to dump the verification trace to the log,
- * so the user can figure out what's wrong with the program
- */
-__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
- const char *fmt, ...)
+static void log_write(struct bpf_verifier_env *env, const char *fmt,
+ va_list args)
{
struct bpf_verifer_log *log = &env->log;
unsigned int n;
- va_list args;

if (!log->level || !log->ubuf || bpf_verifier_log_full(log))
return;

- va_start(args, fmt);
n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args);
- va_end(args);

WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1,
"verifier log line truncated - local buffer too short\n");
@@ -197,14 +190,30 @@ __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
else
log->ubuf = NULL;
}
-EXPORT_SYMBOL_GPL(bpf_verifier_log_write);
-/* Historically bpf_verifier_log_write was called verbose, but the name was too
- * generic for symbol export. The function was renamed, but not the calls in
- * the verifier to avoid complicating backports. Hence the alias below.
+
+/* log_level controls verbosity level of eBPF verifier.
+ * bpf_verifier_log_write() is used to dump the verification trace to the log,
+ * so the user can figure out what's wrong with the program
*/
-static __printf(2, 3) void verbose(struct bpf_verifier_env *env,
- const char *fmt, ...)
- __attribute__((alias("bpf_verifier_log_write")));
+__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
+ const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ log_write(env, fmt, args);
+ va_end(args);
+}
+EXPORT_SYMBOL_GPL(bpf_verifier_log_write);
+
+__printf(2, 3) static void verbose(void *private_data, const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ log_write(private_data, fmt, args);
+ va_end(args);
+}

static bool type_is_pkt_pointer(enum bpf_reg_type type)
{
@@ -4600,10 +4609,11 @@ static int do_check(struct bpf_verifier_env *env)
if (env->log.level) {
const struct bpf_insn_cbs cbs = {
.cb_print = verbose,
+ .private_data = env,
};

verbose(env, "%d: ", insn_idx);
- print_bpf_insn(&cbs, env, insn, env->allow_ptr_leaks);
+ print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
}

if (bpf_prog_is_dev_bound(env->prog->aux)) {
--
2.13.6


2018-03-23 13:35:28

by Quentin Monnet

[permalink] [raw]
Subject: Re: [PATCH 0/2] bpf: Change print_bpf_insn interface

2018-03-23 11:41 UTC+0100 ~ Jiri Olsa <[email protected]>
> hi,
> this patchset removes struct bpf_verifier_env argument
> from print_bpf_insn function (patch 1) and changes user
> space bpftool user to use it that way (patch 2).
>
> thanks,
> jirka
>
> ---
> Jiri Olsa (2):
> bpf: Remove struct bpf_verifier_env argument from print_bpf_insn
> bpftool: Adjust to new print_bpf_insn interface
>
> kernel/bpf/disasm.c | 52 ++++++++++++++++++++++++++--------------------------
> kernel/bpf/disasm.h | 5 +----
> kernel/bpf/verifier.c | 44 +++++++++++++++++++++++++++-----------------
> tools/bpf/bpftool/xlated_dumper.c | 12 ++++++------
> 4 files changed, 60 insertions(+), 53 deletions(-)
>

Thanks, this version looks good to me. Please keep the "Reviewed-by"
tags when resubmitting new versions of your patch sets :)

For the series:
Reviewed-by: Quentin Monnet <[email protected]>

2018-03-23 16:48:50

by Daniel Borkmann

[permalink] [raw]
Subject: Re: [PATCH 0/2] bpf: Change print_bpf_insn interface

On 03/23/2018 02:34 PM, Quentin Monnet wrote:
> 2018-03-23 11:41 UTC+0100 ~ Jiri Olsa <[email protected]>
>> hi,
>> this patchset removes struct bpf_verifier_env argument
>> from print_bpf_insn function (patch 1) and changes user
>> space bpftool user to use it that way (patch 2).
>>
>> thanks,
>> jirka
>>
>> ---
>> Jiri Olsa (2):
>> bpf: Remove struct bpf_verifier_env argument from print_bpf_insn
>> bpftool: Adjust to new print_bpf_insn interface
>>
>> kernel/bpf/disasm.c | 52 ++++++++++++++++++++++++++--------------------------
>> kernel/bpf/disasm.h | 5 +----
>> kernel/bpf/verifier.c | 44 +++++++++++++++++++++++++++-----------------
>> tools/bpf/bpftool/xlated_dumper.c | 12 ++++++------
>> 4 files changed, 60 insertions(+), 53 deletions(-)
>>
>
> Thanks, this version looks good to me. Please keep the "Reviewed-by"
> tags when resubmitting new versions of your patch sets :)
>
> For the series:
> Reviewed-by: Quentin Monnet <[email protected]>

Applied to bpf-next, thanks everyone!