Commit cce4c40b authored by Daniel Xu's avatar Daniel Xu Committed by Alexei Starovoitov
Browse files

bpf: treewide: Align kfunc signatures to prog point-of-view 



Previously, kfunc declarations in bpf_kfuncs.h (and others) used "user
facing" types for kfuncs prototypes while the actual kfunc definitions
used "kernel facing" types. More specifically: bpf_dynptr vs
bpf_dynptr_kern, __sk_buff vs sk_buff, and xdp_md vs xdp_buff.

It wasn't an issue before, as the verifier allows aliased types.
However, since we are now generating kfunc prototypes in vmlinux.h (in
addition to keeping bpf_kfuncs.h around), this conflict creates
compilation errors.

Fix this conflict by using "user facing" types in kfunc definitions.
This results in more casts, but otherwise has no additional runtime
cost.

Note, similar to 5b268d1e ("bpf: Have bpf_rdonly_cast() take a const
pointer"), we also make kfuncs take const arguments where appropriate in
order to make the kfunc more permissive.

Signed-off-by: default avatarDaniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/b58346a63a0e66bc9b7504da751b526b0b189a67.1718207789.git.dxu@dxuuu.xyz


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ec209ad8

fs/verity/measure.c

+3 −2
Original line number Diff line number Diff line
@@ -111,14 +111,15 @@ __bpf_kfunc_start_defs(); 
/**

 * bpf_get_fsverity_digest: read fsverity digest of file

 * @file: file to get digest from

 * @digest_ptr: (out) dynptr for struct fsverity_digest

 * @digest_p: (out) dynptr for struct fsverity_digest

 *

 * Read fsverity_digest of *file* into *digest_ptr*.

 *

 * Return: 0 on success, a negative value on error.

 */

__bpf_kfunc int bpf_get_fsverity_digest(struct file *file, struct bpf_dynptr_kern *digest_ptr)

__bpf_kfunc int bpf_get_fsverity_digest(struct file *file, struct bpf_dynptr *digest_p)

{

	struct bpf_dynptr_kern *digest_ptr = (struct bpf_dynptr_kern *)digest_p;

	const struct inode *inode = file_inode(file);

	u32 dynptr_sz = __bpf_dynptr_size(digest_ptr);

	struct fsverity_digest *arg;

include/linux/bpf.h

+4 −4
Original line number Diff line number Diff line
@@ -3265,8 +3265,8 @@ u32 bpf_sock_convert_ctx_access(enum bpf_access_type type, 
				struct bpf_insn *insn_buf,

				struct bpf_prog *prog,

				u32 *target_size);

int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags,

			       struct bpf_dynptr_kern *ptr);

int bpf_dynptr_from_skb_rdonly(struct __sk_buff *skb, u64 flags,

			       struct bpf_dynptr *ptr);

#else

static inline bool bpf_sock_common_is_valid_access(int off, int size,

						   enum bpf_access_type type,
@@ -3288,8 +3288,8 @@ static inline u32 bpf_sock_convert_ctx_access(enum bpf_access_type type, 
{

	return 0;

}

static inline int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags,

					     struct bpf_dynptr_kern *ptr)

static inline int bpf_dynptr_from_skb_rdonly(struct __sk_buff *skb, u64 flags,

					     struct bpf_dynptr *ptr)

{

	return -EOPNOTSUPP;

}

kernel/bpf/crypto.c

+16 −8
Original line number Diff line number Diff line
@@ -311,11 +311,15 @@ static int bpf_crypto_crypt(const struct bpf_crypto_ctx *ctx, 
 * Decrypts provided buffer using IV data and the crypto context. Crypto context must be configured.

 */

__bpf_kfunc int bpf_crypto_decrypt(struct bpf_crypto_ctx *ctx,

				   const struct bpf_dynptr_kern *src,

				   const struct bpf_dynptr_kern *dst,

				   const struct bpf_dynptr_kern *siv)

				   const struct bpf_dynptr *src,

				   const struct bpf_dynptr *dst,

				   const struct bpf_dynptr *siv)

{

	return bpf_crypto_crypt(ctx, src, dst, siv, true);

	const struct bpf_dynptr_kern *src_kern = (struct bpf_dynptr_kern *)src;

	const struct bpf_dynptr_kern *dst_kern = (struct bpf_dynptr_kern *)dst;

	const struct bpf_dynptr_kern *siv_kern = (struct bpf_dynptr_kern *)siv;



	return bpf_crypto_crypt(ctx, src_kern, dst_kern, siv_kern, true);

}



/**
@@ -328,11 +332,15 @@ __bpf_kfunc int bpf_crypto_decrypt(struct bpf_crypto_ctx *ctx, 
 * Encrypts provided buffer using IV data and the crypto context. Crypto context must be configured.

 */

__bpf_kfunc int bpf_crypto_encrypt(struct bpf_crypto_ctx *ctx,

				   const struct bpf_dynptr_kern *src,

				   const struct bpf_dynptr_kern *dst,

				   const struct bpf_dynptr_kern *siv)

				   const struct bpf_dynptr *src,

				   const struct bpf_dynptr *dst,

				   const struct bpf_dynptr *siv)

{

	return bpf_crypto_crypt(ctx, src, dst, siv, false);

	const struct bpf_dynptr_kern *src_kern = (struct bpf_dynptr_kern *)src;

	const struct bpf_dynptr_kern *dst_kern = (struct bpf_dynptr_kern *)dst;

	const struct bpf_dynptr_kern *siv_kern = (struct bpf_dynptr_kern *)siv;



	return bpf_crypto_crypt(ctx, src_kern, dst_kern, siv_kern, false);

}



__bpf_kfunc_end_defs();

kernel/bpf/helpers.c

+27 −12
Original line number Diff line number Diff line
@@ -2459,9 +2459,10 @@ __bpf_kfunc struct task_struct *bpf_task_from_pid(s32 pid) 
 * provided buffer, with its contents containing the data, if unable to obtain

 * direct pointer)

 */

__bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset,

__bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr *p, u32 offset,

				   void *buffer__opt, u32 buffer__szk)

{

	const struct bpf_dynptr_kern *ptr = (struct bpf_dynptr_kern *)p;

	enum bpf_dynptr_type type;

	u32 len = buffer__szk;

	int err;
@@ -2543,9 +2544,11 @@ __bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset 
 * provided buffer, with its contents containing the data, if unable to obtain

 * direct pointer)

 */

__bpf_kfunc void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr_kern *ptr, u32 offset,

__bpf_kfunc void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr *p, u32 offset,

					void *buffer__opt, u32 buffer__szk)

{

	const struct bpf_dynptr_kern *ptr = (struct bpf_dynptr_kern *)p;



	if (!ptr->data || __bpf_dynptr_is_rdonly(ptr))

		return NULL;
@@ -2571,11 +2574,12 @@ __bpf_kfunc void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr_kern *ptr, u32 o 
	 * will be copied out into the buffer and the user will need to call

	 * bpf_dynptr_write() to commit changes.

	 */

	return bpf_dynptr_slice(ptr, offset, buffer__opt, buffer__szk);

	return bpf_dynptr_slice(p, offset, buffer__opt, buffer__szk);

}



__bpf_kfunc int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 end)

__bpf_kfunc int bpf_dynptr_adjust(const struct bpf_dynptr *p, u32 start, u32 end)

{

	struct bpf_dynptr_kern *ptr = (struct bpf_dynptr_kern *)p;

	u32 size;



	if (!ptr->data || start > end)
@@ -2592,36 +2596,45 @@ __bpf_kfunc int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 en 
	return 0;

}



__bpf_kfunc bool bpf_dynptr_is_null(struct bpf_dynptr_kern *ptr)

__bpf_kfunc bool bpf_dynptr_is_null(const struct bpf_dynptr *p)

{

	struct bpf_dynptr_kern *ptr = (struct bpf_dynptr_kern *)p;



	return !ptr->data;

}



__bpf_kfunc bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr)

__bpf_kfunc bool bpf_dynptr_is_rdonly(const struct bpf_dynptr *p)

{

	struct bpf_dynptr_kern *ptr = (struct bpf_dynptr_kern *)p;



	if (!ptr->data)

		return false;



	return __bpf_dynptr_is_rdonly(ptr);

}



__bpf_kfunc __u32 bpf_dynptr_size(const struct bpf_dynptr_kern *ptr)

__bpf_kfunc __u32 bpf_dynptr_size(const struct bpf_dynptr *p)

{

	struct bpf_dynptr_kern *ptr = (struct bpf_dynptr_kern *)p;



	if (!ptr->data)

		return -EINVAL;



	return __bpf_dynptr_size(ptr);

}



__bpf_kfunc int bpf_dynptr_clone(struct bpf_dynptr_kern *ptr,

				 struct bpf_dynptr_kern *clone__uninit)

__bpf_kfunc int bpf_dynptr_clone(const struct bpf_dynptr *p,

				 struct bpf_dynptr *clone__uninit)

{

	struct bpf_dynptr_kern *clone = (struct bpf_dynptr_kern *)clone__uninit;

	struct bpf_dynptr_kern *ptr = (struct bpf_dynptr_kern *)p;



	if (!ptr->data) {

		bpf_dynptr_set_null(clone__uninit);

		bpf_dynptr_set_null(clone);

		return -EINVAL;

	}



	*clone__uninit = *ptr;

	*clone = *ptr;



	return 0;

}
@@ -2986,7 +2999,9 @@ late_initcall(kfunc_init); 
 */

const void *__bpf_dynptr_data(const struct bpf_dynptr_kern *ptr, u32 len)

{

	return bpf_dynptr_slice(ptr, 0, NULL, len);

	const struct bpf_dynptr *p = (struct bpf_dynptr *)ptr;



	return bpf_dynptr_slice(p, 0, NULL, len);

}



/* Get a pointer to dynptr data up to len bytes for read write access. If

kernel/bpf/verifier.c

+1 −1
Original line number Diff line number Diff line
@@ -10914,7 +10914,7 @@ enum { 
};









BTF_ID_LIST(kf_arg_btf_ids)









BTF_ID(struct, bpf_dynptr_kern)









BTF_ID(struct, bpf_dynptr)









BTF_ID(struct, bpf_list_head)









BTF_ID(struct, bpf_list_node)









BTF_ID(struct, bpf_rb_root)