diff mbox series

[14/14] net: sched: Annotate struct tc_pedit with __counted_by

Message ID 20230922172858.3822653-14-keescook@chromium.org (mailing list archive)
State Changes Requested
Headers show
Series Batch 1: Annotate structs with __counted_by | expand

Commit Message

Kees Cook Sept. 22, 2023, 5:28 p.m. UTC 
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct tc_pedit.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 net/sched/act_pedit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kees Cook Sept. 22, 2023, 6:18 p.m. UTC | #1 
On Fri, Sep 22, 2023 at 10:28:56AM -0700, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct tc_pedit.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Jamal Hadi Salim <jhs@mojatatu.com>
> Cc: Cong Wang <xiyou.wangcong@gmail.com>
> Cc: Jiri Pirko <jiri@resnulli.us>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  net/sched/act_pedit.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> index 1ef8fcfa9997..77c407eff3b0 100644
> --- a/net/sched/act_pedit.c
> +++ b/net/sched/act_pedit.c
> @@ -515,11 +515,11 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
>  		spin_unlock_bh(&p->tcf_lock);
>  		return -ENOBUFS;
>  	}
> +	opt->nkeys = parms->tcfp_nkeys;
>  
>  	memcpy(opt->keys, parms->tcfp_keys,
>  	       flex_array_size(opt, keys, parms->tcfp_nkeys));
>  	opt->index = p->tcf_index;
> -	opt->nkeys = parms->tcfp_nkeys;
>  	opt->flags = parms->tcfp_flags;
>  	opt->action = p->tcf_action;
>  	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
> -- 
> 2.34.1

Gustavo pointed out that the annotation half of this patch in missing.
My mistake! I will figure out where it went. :P Ah, the joys of
splitting up a treewide patch series...
Kees Cook Sept. 22, 2023, 6:23 p.m. UTC | #2 
On Fri, Sep 22, 2023 at 10:28:56AM -0700, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct tc_pedit.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Jamal Hadi Salim <jhs@mojatatu.com>
> Cc: Cong Wang <xiyou.wangcong@gmail.com>
> Cc: Jiri Pirko <jiri@resnulli.us>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  net/sched/act_pedit.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> index 1ef8fcfa9997..77c407eff3b0 100644
> --- a/net/sched/act_pedit.c
> +++ b/net/sched/act_pedit.c
> @@ -515,11 +515,11 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
>  		spin_unlock_bh(&p->tcf_lock);
>  		return -ENOBUFS;
>  	}
> +	opt->nkeys = parms->tcfp_nkeys;
>  
>  	memcpy(opt->keys, parms->tcfp_keys,
>  	       flex_array_size(opt, keys, parms->tcfp_nkeys));
>  	opt->index = p->tcf_index;
> -	opt->nkeys = parms->tcfp_nkeys;
>  	opt->flags = parms->tcfp_flags;
>  	opt->action = p->tcf_action;
>  	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
> -- 
> 2.34.1
> 

Coccinelle was not happy about the #define ...

struct tc_pedit_sel {
	tc_gen;
	unsigned char           nkeys;
	unsigned char           flags;
	struct tc_pedit_key     keys[0];
};

#define tc_pedit tc_pedit_sel

Also, it's not been converted to a proper flexible array...
Gustavo A. R. Silva Sept. 23, 2023, 2:06 a.m. UTC | #3 
On 9/22/23 11:28, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct tc_pedit.

I think the annotation for struct tc_pedit_sel is missing.

Thanks
--
Gustavo

> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Jamal Hadi Salim <jhs@mojatatu.com>
> Cc: Cong Wang <xiyou.wangcong@gmail.com>
> Cc: Jiri Pirko <jiri@resnulli.us>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>   net/sched/act_pedit.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> index 1ef8fcfa9997..77c407eff3b0 100644
> --- a/net/sched/act_pedit.c
> +++ b/net/sched/act_pedit.c
> @@ -515,11 +515,11 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
>   		spin_unlock_bh(&p->tcf_lock);
>   		return -ENOBUFS;
>   	}
> +	opt->nkeys = parms->tcfp_nkeys;
>   
>   	memcpy(opt->keys, parms->tcfp_keys,
>   	       flex_array_size(opt, keys, parms->tcfp_nkeys));
>   	opt->index = p->tcf_index;
> -	opt->nkeys = parms->tcfp_nkeys;
>   	opt->flags = parms->tcfp_flags;
>   	opt->action = p->tcf_action;
>   	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
diff mbox series

Patch

diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 1ef8fcfa9997..77c407eff3b0 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -515,11 +515,11 @@  static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 		spin_unlock_bh(&p->tcf_lock);
 		return -ENOBUFS;
 	}
+	opt->nkeys = parms->tcfp_nkeys;
 
 	memcpy(opt->keys, parms->tcfp_keys,
 	       flex_array_size(opt, keys, parms->tcfp_nkeys));
 	opt->index = p->tcf_index;
-	opt->nkeys = parms->tcfp_nkeys;
 	opt->flags = parms->tcfp_flags;
 	opt->action = p->tcf_action;
 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;