diff mbox series

[bpf-next,v3,2/2] bpf: disallow BPF_LOG_KERNEL log level for bpf(BPF_BTF_LOAD)

Message ID 20211102101536.2958763-3-houtao1@huawei.com (mailing list archive)
State New, archived
Delegated to: BPF
Headers show
Series clean-up for BPF_LOG_KERNEL log level | expand

Checks

Context Check Description
netdev/cover_letter success Series has a cover letter
netdev/fixes_present success Fixes tag not required for -next series
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for bpf-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 3 maintainers not CCed: songliubraving@fb.com john.fastabend@gmail.com kpsingh@kernel.org
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 40 this patch: 40
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Fixes tag looks correct
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 36 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 40 this patch: 40
netdev/header_inline success No static functions without inline keyword in header files
bpf/vmtest-bpf-next fail VM_Test
bpf/vmtest-bpf-next-PR fail PR summary

Commit Message

Hou Tao Nov. 2, 2021, 10:15 a.m. UTC
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>
---
 include/linux/bpf_verifier.h | 7 +++++++
 kernel/bpf/btf.c             | 3 +--
 kernel/bpf/verifier.c        | 6 +++---
 3 files changed, 11 insertions(+), 5 deletions(-)

Comments

Yonghong Song Nov. 2, 2021, 5:38 p.m. UTC | #1
On 11/2/21 3:15 AM, Hou Tao wrote:
> 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>

Acked-by: Yonghong Song <yhs@fb.com>
diff mbox series

Patch

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index c8a78e830fca..a3d17601a5a7 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -396,6 +396,13 @@  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, u32 max_total)
+{
+	return log->len_total >= 128 && log->len_total <= max_total &&
+	       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..657c6b48c616 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, UINT_MAX >> 8)) {
 			err = -EINVAL;
 			goto errout;
 		}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 77beaa46329a..19a52ff384ec 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, UINT_MAX >> 2)) {
+			ret = -EINVAL;
 			goto err_unlock;
+		}
 	}
 
 	if (IS_ERR(btf_vmlinux)) {