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.
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <[email protected]>
---
Cc: Jakub Kicinski <[email protected]>
Cc: Jamal Hadi Salim <[email protected]>
Cc: Cong Wang <[email protected]>
Cc: Jiri Pirko <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: "Gustavo A. R. Silva" <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
include/uapi/linux/tc_act/tc_pedit.h | 2 +-
net/sched/act_pedit.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/tc_act/tc_pedit.h b/include/uapi/linux/tc_act/tc_pedit.h
index f3e61b04fa01..f5cab7fc96ab 100644
--- a/include/uapi/linux/tc_act/tc_pedit.h
+++ b/include/uapi/linux/tc_act/tc_pedit.h
@@ -62,7 +62,7 @@ struct tc_pedit_sel {
tc_gen;
unsigned char nkeys;
unsigned char flags;
- struct tc_pedit_key keys[0];
+ struct tc_pedit_key keys[] __counted_by(nkeys);
};
#define tc_pedit tc_pedit_sel
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 2ef22969f274..21e863d2898c 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
On 2/16/24 17:27, 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.
>
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <[email protected]>
> ---
> Cc: Jakub Kicinski <[email protected]>
> Cc: Jamal Hadi Salim <[email protected]>
> Cc: Cong Wang <[email protected]>
> Cc: Jiri Pirko <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Eric Dumazet <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: "Gustavo A. R. Silva" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
`opt->nkeys` updated before `memcpy()`, looks good to me:
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Thanks!
--
Gustavo
> ---
> include/uapi/linux/tc_act/tc_pedit.h | 2 +-
> net/sched/act_pedit.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/tc_act/tc_pedit.h b/include/uapi/linux/tc_act/tc_pedit.h
> index f3e61b04fa01..f5cab7fc96ab 100644
> --- a/include/uapi/linux/tc_act/tc_pedit.h
> +++ b/include/uapi/linux/tc_act/tc_pedit.h
> @@ -62,7 +62,7 @@ struct tc_pedit_sel {
> tc_gen;
> unsigned char nkeys;
> unsigned char flags;
> - struct tc_pedit_key keys[0];
> + struct tc_pedit_key keys[] __counted_by(nkeys);
> };
>
> #define tc_pedit tc_pedit_sel
> diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> index 2ef22969f274..21e863d2898c 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;
On Fri, Feb 16, 2024 at 7:04 PM Gustavo A. R. Silva
<[email protected]> wrote:
>
>
>
> On 2/16/24 17:27, 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.
> >
> > Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> > Signed-off-by: Kees Cook <[email protected]>
> > ---
> > Cc: Jakub Kicinski <[email protected]>
> > Cc: Jamal Hadi Salim <[email protected]>
> > Cc: Cong Wang <[email protected]>
> > Cc: Jiri Pirko <[email protected]>
> > Cc: "David S. Miller" <[email protected]>
> > Cc: Eric Dumazet <[email protected]>
> > Cc: Paolo Abeni <[email protected]>
> > Cc: "Gustavo A. R. Silva" <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
>
> `opt->nkeys` updated before `memcpy()`, looks good to me:
>
> Reviewed-by: Gustavo A. R. Silva <[email protected]>
Looks good to me.
Acked-by: Jamal Hadi Salim <[email protected]>
cheers,
jamal
> Thanks!
> --
> Gustavo
>
> > ---
> > include/uapi/linux/tc_act/tc_pedit.h | 2 +-
> > net/sched/act_pedit.c | 2 +-
> > 2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/uapi/linux/tc_act/tc_pedit.h b/include/uapi/linux/tc_act/tc_pedit.h
> > index f3e61b04fa01..f5cab7fc96ab 100644
> > --- a/include/uapi/linux/tc_act/tc_pedit.h
> > +++ b/include/uapi/linux/tc_act/tc_pedit.h
> > @@ -62,7 +62,7 @@ struct tc_pedit_sel {
> > tc_gen;
> > unsigned char nkeys;
> > unsigned char flags;
> > - struct tc_pedit_key keys[0];
> > + struct tc_pedit_key keys[] __counted_by(nkeys);
> > };
> >
> > #define tc_pedit tc_pedit_sel
> > diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> > index 2ef22969f274..21e863d2898c 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;
Hello:
This patch was applied to netdev/net-next.git (main)
by David S. Miller <[email protected]>:
On Fri, 16 Feb 2024 15:27:44 -0800 you 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.
>
> [...]
Here is the summary with links:
- net: sched: Annotate struct tc_pedit with __counted_by
https://git.kernel.org/netdev/net-next/c/1e63e5a813fa
You are awesome, thank you!
--
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