On 8/12/22 12:18 PM, Roberto Sassu wrote:
Allow the bpf_dynptr_kern parameter to be specified in kfuncs. Also, ensure
that the dynamic pointer is valid and initialized.
Cc: Joanne Koong <joannelkoong@xxxxxxxxx>
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
---
include/linux/bpf_verifier.h | 3 +++
kernel/bpf/btf.c | 22 ++++++++++++++++++++++
kernel/bpf/verifier.c | 4 ++--
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 2e3bad8640dc..55876fbdbae2 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -560,6 +560,9 @@ int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state
u32 regno);
int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
u32 regno, u32 mem_size);
+bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ enum bpf_arg_type arg_type);
/* this lives here instead of in bpf.h because it needs to dereference tgt_prog */
static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog,
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index e49b3b6d48ad..86e63f2ee5da 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -195,6 +195,10 @@
i < btf_type_vlen(struct_type); \
i++, member++)
+#define stringify_struct(x) \
+ ({ BUILD_BUG_ON(sizeof(struct x) < 0); \
+ __stringify(x); })
+
I'd say lets move this to include/linux/btf.h with a comment explaining the BUILD_BUG_ON()
which ensures the struct actually exits.
If there's ever use outside of BTF, it could be relocated to include/linux/stringify.h.
DEFINE_IDR(btf_idr);
DEFINE_SPINLOCK(btf_idr_lock);
