BPF_LOG_KERNEL is only used internally, so disallow bpf_btf_load()
to set log level as BPF_LOG_KERNEL. The same checking has already
been done in bpf_check(), so factor out a helper to check the
validity of log attributes and use it in both places.
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
include/linux/bpf_verifier.h | 6 ++++++
kernel/bpf/btf.c | 3 +--
kernel/bpf/verifier.c | 6 +++---
3 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index c8a78e830fca..b36a0da8d5cf 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -396,6 +396,12 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
log->level == BPF_LOG_KERNEL);
}
+static inline bool bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log)
+{
+ return (log->len_total >= 128 && log->len_total <= UINT_MAX >> 2 &&
+ log->level && log->ubuf && !(log->level & ~BPF_LOG_MASK));
+}
+
#define BPF_MAX_SUBPROGS 256
struct bpf_subprog_info {
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index dbc3ad07e21b..ea8874eaedac 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4460,8 +4460,7 @@ static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
log->len_total = log_size;
/* log attributes have to be sane */
- if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
- !log->level || !log->ubuf) {
+ if (!bpf_verifier_log_attr_valid(log)) {
err = -EINVAL;
goto errout;
}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 22f0d2292c2c..47ad91cea7e9 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13935,11 +13935,11 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr)
log->ubuf = (char __user *) (unsigned long) attr->log_buf;
log->len_total = attr->log_size;
- ret = -EINVAL;
/* log attributes have to be sane */
- if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 ||
- !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK)
+ if (!bpf_verifier_log_attr_valid(log)) {
+ ret = -EINVAL;
goto err_unlock;
+ }
}
if (IS_ERR(btf_vmlinux)) {
--
2.29.2
