Commit 26d6506a authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'Dynptr refactorings' 

Kumar Kartikeya Dwivedi says:

====================

This is part 1 of https://lore.kernel.org/bpf/20221018135920.726360-1-memxor@gmail.com.
This thread also gives some background on why the refactor is being done:
https://lore.kernel.org/bpf/CAEf4Bzb4beTHgVo+G+jehSj8oCeAjRbRcm6MRe=Gr+cajRBwEw@mail.gmail.com

As requested in patch 6 by Alexei, it only includes patches which
refactors the code, on top of which further fixes will be made in part
2. The refactor itself fixes another issue as a side effect. No
functional change is intended (except a few modified log messages).

Changelog:
----------
v1 -> v2
v1: https://lore.kernel.org/bpf/20221115000130.1967465-1-memxor@gmail.com

 * Address feedback from Joanne and David, add acks

Fixes v1 -> v1
Fixes v1: https://lore.kernel.org/bpf/20221018135920.726360-1-memxor@gmail.com



 * Collect acks from Joanne and David
 * Fix misc nits pointed out by Joanne, David
 * Split move of reg->off alignment check for dynptr into separate
   change (Alexei)
====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 6798152b 292064cc

include/linux/bpf.h

+2 −2
Original line number Diff line number Diff line
@@ -775,7 +775,7 @@ enum bpf_reg_type { 
	PTR_TO_MEM,		 /* reg points to valid memory region */

	PTR_TO_BUF,		 /* reg points to a read/write buffer */

	PTR_TO_FUNC,		 /* reg points to a bpf program function */

	PTR_TO_DYNPTR,		 /* reg points to a dynptr */

	CONST_PTR_TO_DYNPTR,	 /* reg points to a const struct bpf_dynptr */

	__BPF_REG_TYPE_MAX,



	/* Extended reg_types. */
@@ -2828,7 +2828,7 @@ void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data, 
		     enum bpf_dynptr_type type, u32 offset, u32 size);

void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr);

int bpf_dynptr_check_size(u32 size);

u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr);

u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr);



#ifdef CONFIG_BPF_LSM

void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype);

include/linux/bpf_verifier.h

+3 −5
Original line number Diff line number Diff line
@@ -615,11 +615,9 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env, 
			   enum bpf_arg_type arg_type);

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);

bool is_dynptr_type_expected(struct bpf_verifier_env *env,

			     struct bpf_reg_state *reg,

			     enum bpf_arg_type arg_type);

struct bpf_call_arg_meta;

int process_dynptr_func(struct bpf_verifier_env *env, int regno,

			enum bpf_arg_type arg_type, struct bpf_call_arg_meta *meta);



/* 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,

include/uapi/linux/bpf.h

+4 −4
Original line number Diff line number Diff line
@@ -5293,7 +5293,7 @@ union bpf_attr { 
 *	Return

 *		Nothing. Always succeeds.

 *

 * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags)

 * long bpf_dynptr_read(void *dst, u32 len, const struct bpf_dynptr *src, u32 offset, u64 flags)

 *	Description

 *		Read *len* bytes from *src* into *dst*, starting from *offset*

 *		into *src*.
@@ -5303,7 +5303,7 @@ union bpf_attr { 
 *		of *src*'s data, -EINVAL if *src* is an invalid dynptr or if

 *		*flags* is not 0.

 *

 * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len, u64 flags)

 * long bpf_dynptr_write(const struct bpf_dynptr *dst, u32 offset, void *src, u32 len, u64 flags)

 *	Description

 *		Write *len* bytes from *src* into *dst*, starting from *offset*

 *		into *dst*.
@@ -5313,7 +5313,7 @@ union bpf_attr { 
 *		of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst*

 *		is a read-only dynptr or if *flags* is not 0.

 *

 * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len)

 * void *bpf_dynptr_data(const struct bpf_dynptr *ptr, u32 offset, u32 len)

 *	Description

 *		Get a pointer to the underlying dynptr data.

 *
@@ -5414,7 +5414,7 @@ union bpf_attr { 
 *		Drain samples from the specified user ring buffer, and invoke

 *		the provided callback for each such sample:

 *

 *		long (\*callback_fn)(struct bpf_dynptr \*dynptr, void \*ctx);

 *		long (\*callback_fn)(const struct bpf_dynptr \*dynptr, void \*ctx);

 *

 *		If **callback_fn** returns 0, the helper will continue to try

 *		and drain the next sample, up to a maximum of

kernel/bpf/helpers.c

+19 −11
Original line number Diff line number Diff line
@@ -1404,7 +1404,7 @@ static const struct bpf_func_proto bpf_kptr_xchg_proto = { 
#define DYNPTR_SIZE_MASK	0xFFFFFF

#define DYNPTR_RDONLY_BIT	BIT(31)



static bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr)

static bool bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr)

{

	return ptr->size & DYNPTR_RDONLY_BIT;

}
@@ -1414,7 +1414,7 @@ static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_typ 
	ptr->size |= type << DYNPTR_TYPE_SHIFT;

}



u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)

u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr)

{

	return ptr->size & DYNPTR_SIZE_MASK;

}
@@ -1438,7 +1438,7 @@ void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr) 
	memset(ptr, 0, sizeof(*ptr));

}



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

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

{

	u32 size = bpf_dynptr_get_size(ptr);
@@ -1483,7 +1483,7 @@ static const struct bpf_func_proto bpf_dynptr_from_mem_proto = { 
	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT,

};



BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, struct bpf_dynptr_kern *, src,

BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src,

	   u32, offset, u64, flags)

{

	int err;
@@ -1495,7 +1495,11 @@ BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, struct bpf_dynptr_kern *, src 
	if (err)

		return err;



	memcpy(dst, src->data + src->offset + offset, len);

	/* Source and destination may possibly overlap, hence use memmove to

	 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr

	 * pointing to overlapping PTR_TO_MAP_VALUE regions.

	 */

	memmove(dst, src->data + src->offset + offset, len);



	return 0;

}
@@ -1506,12 +1510,12 @@ static const struct bpf_func_proto bpf_dynptr_read_proto = { 
	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,

	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,

	.arg3_type	= ARG_PTR_TO_DYNPTR,

	.arg3_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,

	.arg4_type	= ARG_ANYTHING,

	.arg5_type	= ARG_ANYTHING,

};



BPF_CALL_5(bpf_dynptr_write, struct bpf_dynptr_kern *, dst, u32, offset, void *, src,

BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, void *, src,

	   u32, len, u64, flags)

{

	int err;
@@ -1523,7 +1527,11 @@ BPF_CALL_5(bpf_dynptr_write, struct bpf_dynptr_kern *, dst, u32, offset, void *, 
	if (err)

		return err;



	memcpy(dst->data + dst->offset + offset, src, len);

	/* Source and destination may possibly overlap, hence use memmove to

	 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr

	 * pointing to overlapping PTR_TO_MAP_VALUE regions.

	 */

	memmove(dst->data + dst->offset + offset, src, len);



	return 0;

}
@@ -1532,14 +1540,14 @@ static const struct bpf_func_proto bpf_dynptr_write_proto = { 
	.func		= bpf_dynptr_write,

	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_DYNPTR,

	.arg1_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,

	.arg2_type	= ARG_ANYTHING,

	.arg3_type	= ARG_PTR_TO_MEM | MEM_RDONLY,

	.arg4_type	= ARG_CONST_SIZE_OR_ZERO,

	.arg5_type	= ARG_ANYTHING,

};



BPF_CALL_3(bpf_dynptr_data, struct bpf_dynptr_kern *, ptr, u32, offset, u32, len)

BPF_CALL_3(bpf_dynptr_data, const struct bpf_dynptr_kern *, ptr, u32, offset, u32, len)

{

	int err;
@@ -1560,7 +1568,7 @@ static const struct bpf_func_proto bpf_dynptr_data_proto = { 
	.func		= bpf_dynptr_data,

	.gpl_only	= false,

	.ret_type	= RET_PTR_TO_DYNPTR_MEM_OR_NULL,

	.arg1_type	= ARG_PTR_TO_DYNPTR,

	.arg1_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,

	.arg2_type	= ARG_ANYTHING,

	.arg3_type	= ARG_CONST_ALLOC_SIZE_OR_ZERO,

};

kernel/bpf/verifier.c

+285 −147

File changed.

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