| Message ID | 1f64c8daa2a98f0808d7f834013cb36fe2eb2bff.1553085664.git.dcaratti@redhat.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | net/sched: validate the control action with all the other parameters | expand |
diff --git a/include/net/tc_act/tc_gact.h b/include/net/tc_act/tc_gact.h index ee8d005f56fc..eb8f01c819e6 100644 --- a/include/net/tc_act/tc_gact.h +++ b/include/net/tc_act/tc_gact.h @@ -56,7 +56,7 @@ static inline bool is_tcf_gact_goto_chain(const struct tc_action *a) static inline u32 tcf_gact_goto_chain_index(const struct tc_action *a) { - return a->goto_chain->index; + return READ_ONCE(a->tcfa_action) & TC_ACT_EXT_VAL_MASK; } #endif /* __NET_TC_GACT_H */
callers of tcf_gact_goto_chain_index() can potentially read an old value of the chain index, or even dereference a NULL 'goto_chain' pointer, because 'goto_chain' and 'tcfa_action' are read in the traffic path without caring of concurrent write in the control path. The most recent value of chain index can be read also from a->tcfa_action (it's encoded there together with TC_ACT_GOTO_CHAIN bits), so we don't really need to dereference 'goto_chain': just read the chain id from the control action. Fixes: e457d86ada27 ("net: sched: add couple of goto_chain helpers") Signed-off-by: Davide Caratti <dcaratti@redhat.com> --- include/net/tc_act/tc_gact.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)