From: Hou Tao houtao1@huawei.com
[ Upstream commit 866de407444398bc8140ea70de1dba5f91cc34ac ]
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.
Fixes: 8580ac9404f6 ("bpf: Process in-kernel BTF") Signed-off-by: Hou Tao houtao1@huawei.com Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Yonghong Song yhs@fb.com Acked-by: Martin KaFai Lau kafai@fb.com Link: https://lore.kernel.org/bpf/20211203053001.740945-1-houtao1@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/bpf_verifier.h | 7 +++++++ kernel/bpf/btf.c | 3 +-- kernel/bpf/verifier.c | 6 +++--- 3 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 6e330ff2f28df..391bc1480dfb1 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -367,6 +367,13 @@ 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 72534a6f4b96e..dc497eaf22663 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4135,8 +4135,7 @@ static struct btf *btf_parse(void __user *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 >> 2 || - !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 b43c9de34a2c2..c623c3e549210 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -12349,11 +12349,11 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, 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)) {