net: sched: Annotate struct tc_pedit with __counted_by

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 <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kees Cook 2024-02-16 15:27:44 -08:00 committed by David S. Miller
parent da4a154ca2
commit 1e63e5a813
2 changed files with 2 additions and 2 deletions

View File

@ -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

View File

@ -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;