Commit 26662d73 authored by Joanne Koong's avatar Joanne Koong Committed by Daniel Borkmann
Browse files

bpf: Add bpf_dynptr_size 



bpf_dynptr_size returns the number of usable bytes in a dynptr.

Signed-off-by: default avatarJoanne Koong <joannelkoong@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230420071414.570108-4-joannelkoong@gmail.com
parent 540ccf96

include/linux/bpf.h

+1 −1
Original line number Diff line number Diff line
@@ -1197,7 +1197,7 @@ enum bpf_dynptr_type { 
};



int bpf_dynptr_check_size(u32 size);

u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr);

u32 __bpf_dynptr_size(const struct bpf_dynptr_kern *ptr);



#ifdef CONFIG_BPF_JIT

int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr);

kernel/bpf/helpers.c

+12 −3
Original line number Diff line number Diff line
@@ -1443,7 +1443,7 @@ static enum bpf_dynptr_type bpf_dynptr_get_type(const struct bpf_dynptr_kern *pt 
	return (ptr->size & ~(DYNPTR_RDONLY_BIT)) >> DYNPTR_TYPE_SHIFT;

}



u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr)

u32 __bpf_dynptr_size(const struct bpf_dynptr_kern *ptr)

{

	return ptr->size & DYNPTR_SIZE_MASK;

}
@@ -1476,7 +1476,7 @@ void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr) 


static int bpf_dynptr_check_off_len(const struct bpf_dynptr_kern *ptr, u32 offset, u32 len)

{

	u32 size = bpf_dynptr_get_size(ptr);

	u32 size = __bpf_dynptr_size(ptr);



	if (len > size || offset > size - len)

		return -E2BIG;
@@ -2311,7 +2311,7 @@ __bpf_kfunc int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 en 
	if (!ptr->data || start > end)

		return -EINVAL;



	size = bpf_dynptr_get_size(ptr);

	size = __bpf_dynptr_size(ptr);



	if (start > size || end > size)

		return -ERANGE;
@@ -2335,6 +2335,14 @@ __bpf_kfunc bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr) 
	return __bpf_dynptr_is_rdonly(ptr);

}



__bpf_kfunc __u32 bpf_dynptr_size(const struct bpf_dynptr_kern *ptr)

{

	if (!ptr->data)

		return -EINVAL;



	return __bpf_dynptr_size(ptr);

}



__bpf_kfunc void *bpf_cast_to_kern_ctx(void *obj)

{

	return obj;
@@ -2410,6 +2418,7 @@ BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY) 
BTF_ID_FLAGS(func, bpf_dynptr_adjust)

BTF_ID_FLAGS(func, bpf_dynptr_is_null)

BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly)

BTF_ID_FLAGS(func, bpf_dynptr_size)

BTF_SET8_END(common_btf_ids)



static const struct btf_kfunc_id_set common_kfunc_set = {

kernel/trace/bpf_trace.c

+2 −2
Original line number Diff line number Diff line
@@ -1349,9 +1349,9 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr, 
	}



	return verify_pkcs7_signature(data_ptr->data,

				      bpf_dynptr_get_size(data_ptr),

				      __bpf_dynptr_size(data_ptr),

				      sig_ptr->data,

				      bpf_dynptr_get_size(sig_ptr),

				      __bpf_dynptr_size(sig_ptr),

				      trusted_keyring->key,

				      VERIFYING_UNSPECIFIED_SIGNATURE, NULL,

				      NULL);