All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH bpf-next v1] bpf: verifier cleanups
@ 2022-08-02 21:46 Joanne Koong
  2022-08-03  8:15 ` Jiri Olsa
  2022-08-08 16:00 ` patchwork-bot+netdevbpf
  0 siblings, 2 replies; 3+ messages in thread
From: Joanne Koong @ 2022-08-02 21:46 UTC (permalink / raw)
  To: bpf; +Cc: andrii, daniel, ast, Joanne Koong

This patch cleans up a few things in the verifier:
  * type_is_pkt_pointer():
    Future work (skb + xdp dynptrs [0]) will be using the reg type
    PTR_TO_PACKET | PTR_MAYBE_NULL. type_is_pkt_pointer() should return
    true for any type whose base type is PTR_TO_PACKET, regardless of
    flags attached to it.

  * reg_type_may_be_refcounted_or_null():
    Get the base type at the start of the function to avoid
    having to recompute it / improve readability

  * check_func_proto(): remove unnecessary 'meta' arg

  * check_helper_call():
    Use switch casing on the base type of return value instead of
    nested ifs on the full type

There are no functional behavior changes.

[0] https://lore.kernel.org/bpf/20220726184706.954822-1-joannelkoong@gmail.com/

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 kernel/bpf/verifier.c | 50 +++++++++++++++++++++++++++----------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 096fdac70165..843a966cd02b 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -427,6 +427,7 @@ static void verbose_invalid_scalar(struct bpf_verifier_env *env,
 
 static bool type_is_pkt_pointer(enum bpf_reg_type type)
 {
+	type = base_type(type);
 	return type == PTR_TO_PACKET ||
 	       type == PTR_TO_PACKET_META;
 }
@@ -456,10 +457,9 @@ static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
 
 static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
 {
-	return base_type(type) == PTR_TO_SOCKET ||
-		base_type(type) == PTR_TO_TCP_SOCK ||
-		base_type(type) == PTR_TO_MEM ||
-		base_type(type) == PTR_TO_BTF_ID;
+	type = base_type(type);
+	return type == PTR_TO_SOCKET || type == PTR_TO_TCP_SOCK ||
+		type == PTR_TO_MEM || type == PTR_TO_BTF_ID;
 }
 
 static bool type_is_rdonly_mem(u32 type)
@@ -6498,8 +6498,7 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn)
 	return true;
 }
 
-static int check_func_proto(const struct bpf_func_proto *fn, int func_id,
-			    struct bpf_call_arg_meta *meta)
+static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
 {
 	return check_raw_mode_ok(fn) &&
 	       check_arg_pair_ok(fn) &&
@@ -7218,7 +7217,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 	memset(&meta, 0, sizeof(meta));
 	meta.pkt_access = fn->pkt_access;
 
-	err = check_func_proto(fn, func_id, &meta);
+	err = check_func_proto(fn, func_id);
 	if (err) {
 		verbose(env, "kernel subsystem misconfigured func %s#%d\n",
 			func_id_name(func_id), func_id);
@@ -7359,13 +7358,17 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 
 	/* update return register (already marked as written above) */
 	ret_type = fn->ret_type;
-	ret_flag = type_flag(fn->ret_type);
-	if (ret_type == RET_INTEGER) {
+	ret_flag = type_flag(ret_type);
+
+	switch (base_type(ret_type)) {
+	case RET_INTEGER:
 		/* sets type to SCALAR_VALUE */
 		mark_reg_unknown(env, regs, BPF_REG_0);
-	} else if (ret_type == RET_VOID) {
+		break;
+	case RET_VOID:
 		regs[BPF_REG_0].type = NOT_INIT;
-	} else if (base_type(ret_type) == RET_PTR_TO_MAP_VALUE) {
+		break;
+	case RET_PTR_TO_MAP_VALUE:
 		/* There is no offset yet applied, variable or fixed */
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		/* remember map_ptr, so that check_map_access()
@@ -7384,20 +7387,26 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 		    map_value_has_spin_lock(meta.map_ptr)) {
 			regs[BPF_REG_0].id = ++env->id_gen;
 		}
-	} else if (base_type(ret_type) == RET_PTR_TO_SOCKET) {
+		break;
+	case RET_PTR_TO_SOCKET:
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
-	} else if (base_type(ret_type) == RET_PTR_TO_SOCK_COMMON) {
+		break;
+	case RET_PTR_TO_SOCK_COMMON:
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
-	} else if (base_type(ret_type) == RET_PTR_TO_TCP_SOCK) {
+		break;
+	case RET_PTR_TO_TCP_SOCK:
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
-	} else if (base_type(ret_type) == RET_PTR_TO_ALLOC_MEM) {
+		break;
+	case RET_PTR_TO_ALLOC_MEM:
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
 		regs[BPF_REG_0].mem_size = meta.mem_size;
-	} else if (base_type(ret_type) == RET_PTR_TO_MEM_OR_BTF_ID) {
+		break;
+	case RET_PTR_TO_MEM_OR_BTF_ID:
+	{
 		const struct btf_type *t;
 
 		mark_reg_known_zero(env, regs, BPF_REG_0);
@@ -7429,7 +7438,10 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 			regs[BPF_REG_0].btf = meta.ret_btf;
 			regs[BPF_REG_0].btf_id = meta.ret_btf_id;
 		}
-	} else if (base_type(ret_type) == RET_PTR_TO_BTF_ID) {
+		break;
+	}
+	case RET_PTR_TO_BTF_ID:
+	{
 		struct btf *ret_btf;
 		int ret_btf_id;
 
@@ -7450,7 +7462,9 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 		}
 		regs[BPF_REG_0].btf = ret_btf;
 		regs[BPF_REG_0].btf_id = ret_btf_id;
-	} else {
+		break;
+	}
+	default:
 		verbose(env, "unknown return type %u of func %s#%d\n",
 			base_type(ret_type), func_id_name(func_id), func_id);
 		return -EINVAL;
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v1] bpf: verifier cleanups
  2022-08-02 21:46 [PATCH bpf-next v1] bpf: verifier cleanups Joanne Koong
@ 2022-08-03  8:15 ` Jiri Olsa
  2022-08-08 16:00 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: Jiri Olsa @ 2022-08-03  8:15 UTC (permalink / raw)
  To: Joanne Koong; +Cc: bpf, andrii, daniel, ast

On Tue, Aug 02, 2022 at 02:46:38PM -0700, Joanne Koong wrote:
> This patch cleans up a few things in the verifier:
>   * type_is_pkt_pointer():
>     Future work (skb + xdp dynptrs [0]) will be using the reg type
>     PTR_TO_PACKET | PTR_MAYBE_NULL. type_is_pkt_pointer() should return
>     true for any type whose base type is PTR_TO_PACKET, regardless of
>     flags attached to it.
> 
>   * reg_type_may_be_refcounted_or_null():
>     Get the base type at the start of the function to avoid
>     having to recompute it / improve readability
> 
>   * check_func_proto(): remove unnecessary 'meta' arg
> 
>   * check_helper_call():
>     Use switch casing on the base type of return value instead of
>     nested ifs on the full type
> 
> There are no functional behavior changes.
> 
> [0] https://lore.kernel.org/bpf/20220726184706.954822-1-joannelkoong@gmail.com/
> 
> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>

LGTM

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

> ---
>  kernel/bpf/verifier.c | 50 +++++++++++++++++++++++++++----------------
>  1 file changed, 32 insertions(+), 18 deletions(-)
> 
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 096fdac70165..843a966cd02b 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -427,6 +427,7 @@ static void verbose_invalid_scalar(struct bpf_verifier_env *env,
>  
>  static bool type_is_pkt_pointer(enum bpf_reg_type type)
>  {
> +	type = base_type(type);
>  	return type == PTR_TO_PACKET ||
>  	       type == PTR_TO_PACKET_META;
>  }
> @@ -456,10 +457,9 @@ static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
>  
>  static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
>  {
> -	return base_type(type) == PTR_TO_SOCKET ||
> -		base_type(type) == PTR_TO_TCP_SOCK ||
> -		base_type(type) == PTR_TO_MEM ||
> -		base_type(type) == PTR_TO_BTF_ID;
> +	type = base_type(type);
> +	return type == PTR_TO_SOCKET || type == PTR_TO_TCP_SOCK ||
> +		type == PTR_TO_MEM || type == PTR_TO_BTF_ID;
>  }
>  
>  static bool type_is_rdonly_mem(u32 type)
> @@ -6498,8 +6498,7 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn)
>  	return true;
>  }
>  
> -static int check_func_proto(const struct bpf_func_proto *fn, int func_id,
> -			    struct bpf_call_arg_meta *meta)
> +static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
>  {
>  	return check_raw_mode_ok(fn) &&
>  	       check_arg_pair_ok(fn) &&
> @@ -7218,7 +7217,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
>  	memset(&meta, 0, sizeof(meta));
>  	meta.pkt_access = fn->pkt_access;
>  
> -	err = check_func_proto(fn, func_id, &meta);
> +	err = check_func_proto(fn, func_id);
>  	if (err) {
>  		verbose(env, "kernel subsystem misconfigured func %s#%d\n",
>  			func_id_name(func_id), func_id);
> @@ -7359,13 +7358,17 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
>  
>  	/* update return register (already marked as written above) */
>  	ret_type = fn->ret_type;
> -	ret_flag = type_flag(fn->ret_type);
> -	if (ret_type == RET_INTEGER) {
> +	ret_flag = type_flag(ret_type);
> +
> +	switch (base_type(ret_type)) {
> +	case RET_INTEGER:
>  		/* sets type to SCALAR_VALUE */
>  		mark_reg_unknown(env, regs, BPF_REG_0);
> -	} else if (ret_type == RET_VOID) {
> +		break;
> +	case RET_VOID:
>  		regs[BPF_REG_0].type = NOT_INIT;
> -	} else if (base_type(ret_type) == RET_PTR_TO_MAP_VALUE) {
> +		break;
> +	case RET_PTR_TO_MAP_VALUE:
>  		/* There is no offset yet applied, variable or fixed */
>  		mark_reg_known_zero(env, regs, BPF_REG_0);
>  		/* remember map_ptr, so that check_map_access()
> @@ -7384,20 +7387,26 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
>  		    map_value_has_spin_lock(meta.map_ptr)) {
>  			regs[BPF_REG_0].id = ++env->id_gen;
>  		}
> -	} else if (base_type(ret_type) == RET_PTR_TO_SOCKET) {
> +		break;
> +	case RET_PTR_TO_SOCKET:
>  		mark_reg_known_zero(env, regs, BPF_REG_0);
>  		regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
> -	} else if (base_type(ret_type) == RET_PTR_TO_SOCK_COMMON) {
> +		break;
> +	case RET_PTR_TO_SOCK_COMMON:
>  		mark_reg_known_zero(env, regs, BPF_REG_0);
>  		regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
> -	} else if (base_type(ret_type) == RET_PTR_TO_TCP_SOCK) {
> +		break;
> +	case RET_PTR_TO_TCP_SOCK:
>  		mark_reg_known_zero(env, regs, BPF_REG_0);
>  		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
> -	} else if (base_type(ret_type) == RET_PTR_TO_ALLOC_MEM) {
> +		break;
> +	case RET_PTR_TO_ALLOC_MEM:
>  		mark_reg_known_zero(env, regs, BPF_REG_0);
>  		regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
>  		regs[BPF_REG_0].mem_size = meta.mem_size;
> -	} else if (base_type(ret_type) == RET_PTR_TO_MEM_OR_BTF_ID) {
> +		break;
> +	case RET_PTR_TO_MEM_OR_BTF_ID:
> +	{
>  		const struct btf_type *t;
>  
>  		mark_reg_known_zero(env, regs, BPF_REG_0);
> @@ -7429,7 +7438,10 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
>  			regs[BPF_REG_0].btf = meta.ret_btf;
>  			regs[BPF_REG_0].btf_id = meta.ret_btf_id;
>  		}
> -	} else if (base_type(ret_type) == RET_PTR_TO_BTF_ID) {
> +		break;
> +	}
> +	case RET_PTR_TO_BTF_ID:
> +	{
>  		struct btf *ret_btf;
>  		int ret_btf_id;
>  
> @@ -7450,7 +7462,9 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
>  		}
>  		regs[BPF_REG_0].btf = ret_btf;
>  		regs[BPF_REG_0].btf_id = ret_btf_id;
> -	} else {
> +		break;
> +	}
> +	default:
>  		verbose(env, "unknown return type %u of func %s#%d\n",
>  			base_type(ret_type), func_id_name(func_id), func_id);
>  		return -EINVAL;
> -- 
> 2.30.2
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v1] bpf: verifier cleanups
  2022-08-02 21:46 [PATCH bpf-next v1] bpf: verifier cleanups Joanne Koong
  2022-08-03  8:15 ` Jiri Olsa
@ 2022-08-08 16:00 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-08-08 16:00 UTC (permalink / raw)
  To: Joanne Koong; +Cc: bpf, andrii, daniel, ast

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Tue,  2 Aug 2022 14:46:38 -0700 you wrote:
> This patch cleans up a few things in the verifier:
>   * type_is_pkt_pointer():
>     Future work (skb + xdp dynptrs [0]) will be using the reg type
>     PTR_TO_PACKET | PTR_MAYBE_NULL. type_is_pkt_pointer() should return
>     true for any type whose base type is PTR_TO_PACKET, regardless of
>     flags attached to it.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v1] bpf: verifier cleanups
    https://git.kernel.org/bpf/bpf-next/c/0c9a7a7e2049

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-08-08 16:00 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-08-02 21:46 [PATCH bpf-next v1] bpf: verifier cleanups Joanne Koong
2022-08-03  8:15 ` Jiri Olsa
2022-08-08 16:00 ` patchwork-bot+netdevbpf

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.