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From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Mon, 9 Oct 2017 10:30:10 -0700
Subject: bpf: encapsulate verifier log state into a structure
Origin: https://git.kernel.org/linus/e7bf8249e8f1bac64885eeccb55bcf6111901a81
Put the loose log_* variables into a structure. This will make
it simpler to remove the global verifier state in following patches.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/linux/bpf_verifier.h | 13 ++++++++++
kernel/bpf/verifier.c | 57 +++++++++++++++++++++++---------------------
2 files changed, 43 insertions(+), 27 deletions(-)
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -115,6 +115,19 @@ struct bpf_insn_aux_data {
#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
+struct bpf_verifer_log {
+ u32 level;
+ char *kbuf;
+ char __user *ubuf;
+ u32 len_used;
+ u32 len_total;
+};
+
+static inline bool bpf_verifier_log_full(const struct bpf_verifer_log *log)
+{
+ return log->len_used >= log->len_total - 1;
+}
+
struct bpf_verifier_env;
struct bpf_ext_analyzer_ops {
int (*insn_hook)(struct bpf_verifier_env *env,
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -156,8 +156,7 @@ struct bpf_call_arg_meta {
/* verbose verifier prints what it's seeing
* bpf_check() is called under lock, so no race to access these global vars
*/
-static u32 log_level, log_size, log_len;
-static char *log_buf;
+static struct bpf_verifer_log verifier_log;
static DEFINE_MUTEX(bpf_verifier_lock);
@@ -167,13 +166,15 @@ static DEFINE_MUTEX(bpf_verifier_lock);
*/
static __printf(1, 2) void verbose(const char *fmt, ...)
{
+ struct bpf_verifer_log *log = &verifier_log;
va_list args;
- if (log_level == 0 || log_len >= log_size - 1)
+ if (!log->level || bpf_verifier_log_full(log))
return;
va_start(args, fmt);
- log_len += vscnprintf(log_buf + log_len, log_size - log_len, fmt, args);
+ log->len_used += vscnprintf(log->kbuf + log->len_used,
+ log->len_total - log->len_used, fmt, args);
va_end(args);
}
@@ -834,7 +835,7 @@ static int check_map_access(struct bpf_v
* need to try adding each of min_value and max_value to off
* to make sure our theoretical access will be safe.
*/
- if (log_level)
+ if (verifier_log.level)
print_verifier_state(state);
/* The minimum value is only important with signed
* comparisons where we can't assume the floor of a
@@ -2915,7 +2916,7 @@ static int check_cond_jmp_op(struct bpf_
verbose("R%d pointer comparison prohibited\n", insn->dst_reg);
return -EACCES;
}
- if (log_level)
+ if (verifier_log.level)
print_verifier_state(this_branch);
return 0;
}
@@ -3633,7 +3634,7 @@ static int do_check(struct bpf_verifier_
return err;
if (err == 1) {
/* found equivalent state, can prune the search */
- if (log_level) {
+ if (verifier_log.level) {
if (do_print_state)
verbose("\nfrom %d to %d: safe\n",
prev_insn_idx, insn_idx);
@@ -3646,8 +3647,9 @@ static int do_check(struct bpf_verifier_
if (need_resched())
cond_resched();
- if (log_level > 1 || (log_level && do_print_state)) {
- if (log_level > 1)
+ if (verifier_log.level > 1 ||
+ (verifier_log.level && do_print_state)) {
+ if (verifier_log.level > 1)
verbose("%d:", insn_idx);
else
verbose("\nfrom %d to %d:",
@@ -3656,7 +3658,7 @@ static int do_check(struct bpf_verifier_
do_print_state = false;
}
- if (log_level) {
+ if (verifier_log.level) {
verbose("%d: ", insn_idx);
print_bpf_insn(env, insn);
}
@@ -4307,7 +4309,7 @@ static void free_states(struct bpf_verif
int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
{
- char __user *log_ubuf = NULL;
+ struct bpf_verifer_log *log = &verifier_log;
struct bpf_verifier_env *env;
int ret = -EINVAL;
@@ -4332,23 +4334,23 @@ int bpf_check(struct bpf_prog **prog, un
/* user requested verbose verifier output
* and supplied buffer to store the verification trace
*/
- log_level = attr->log_level;
- log_ubuf = (char __user *) (unsigned long) attr->log_buf;
- log_size = attr->log_size;
- log_len = 0;
+ log->level = attr->log_level;
+ log->ubuf = (char __user *) (unsigned long) attr->log_buf;
+ log->len_total = attr->log_size;
+ log->len_used = 0;
ret = -EINVAL;
- /* log_* values have to be sane */
- if (log_size < 128 || log_size > UINT_MAX >> 8 ||
- log_level == 0 || log_ubuf == NULL)
+ /* log attributes have to be sane */
+ if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
+ !log->level || !log->ubuf)
goto err_unlock;
ret = -ENOMEM;
- log_buf = vmalloc(log_size);
- if (!log_buf)
+ log->kbuf = vmalloc(log->len_total);
+ if (!log->kbuf)
goto err_unlock;
} else {
- log_level = 0;
+ log->level = 0;
}
env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
@@ -4385,15 +4387,16 @@ skip_full_check:
if (ret == 0)
ret = fixup_bpf_calls(env);
- if (log_level && log_len >= log_size - 1) {
- BUG_ON(log_len >= log_size);
+ if (log->level && bpf_verifier_log_full(log)) {
+ BUG_ON(log->len_used >= log->len_total);
/* verifier log exceeded user supplied buffer */
ret = -ENOSPC;
/* fall through to return what was recorded */
}
/* copy verifier log back to user space including trailing zero */
- if (log_level && copy_to_user(log_ubuf, log_buf, log_len + 1) != 0) {
+ if (log->level && copy_to_user(log->ubuf, log->kbuf,
+ log->len_used + 1) != 0) {
ret = -EFAULT;
goto free_log_buf;
}
@@ -4420,8 +4423,8 @@ skip_full_check:
}
free_log_buf:
- if (log_level)
- vfree(log_buf);
+ if (log->level)
+ vfree(log->kbuf);
if (!env->prog->aux->used_maps)
/* if we didn't copy map pointers into bpf_prog_info, release
* them now. Otherwise free_bpf_prog_info() will release them.
@@ -4458,7 +4461,7 @@ int bpf_analyzer(struct bpf_prog *prog,
/* grab the mutex to protect few globals used by verifier */
mutex_lock(&bpf_verifier_lock);
- log_level = 0;
+ verifier_log.level = 0;
env->strict_alignment = false;
if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
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