From 2b73bc65e2771372c818db7955709c8caedbf8b9 Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Fri, 10 Feb 2012 05:43:38 +0000 Subject: [PATCH] netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m When the netprio_cgroup module is not loaded, net_prio_subsys_id is -1, and so sock_update_prioidx() accesses cgroup_subsys array with negative index subsys[-1]. Make the code resembles cls_cgroup code, which is bug free. Origionally-authored-by: Li Zefan Signed-off-by: Li Zefan Signed-off-by: Neil Horman CC: "David S. Miller" Signed-off-by: David S. Miller --- include/net/netprio_cgroup.h | 48 ++++++++++++++++++++++++++++++------ net/core/sock.c | 7 ++---- 2 files changed, 42 insertions(+), 13 deletions(-) diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h index 7b2d43139c8e..d58fdec47597 100644 --- a/include/net/netprio_cgroup.h +++ b/include/net/netprio_cgroup.h @@ -37,19 +37,51 @@ extern int net_prio_subsys_id; extern void sock_update_netprioidx(struct sock *sk); -static inline struct cgroup_netprio_state - *task_netprio_state(struct task_struct *p) +#if IS_BUILTIN(CONFIG_NETPRIO_CGROUP) + +static inline u32 task_netprioidx(struct task_struct *p) { -#if IS_ENABLED(CONFIG_NETPRIO_CGROUP) - return container_of(task_subsys_state(p, net_prio_subsys_id), - struct cgroup_netprio_state, css); -#else - return NULL; -#endif + struct cgroup_netprio_state *state; + u32 idx; + + rcu_read_lock(); + state = container_of(task_subsys_state(p, net_prio_subsys_id), + struct cgroup_netprio_state, css); + idx = state->prioidx; + rcu_read_unlock(); + return idx; +} + +#elif IS_MODULE(CONFIG_NETPRIO_CGROUP) + +static inline u32 task_netprioidx(struct task_struct *p) +{ + struct cgroup_netprio_state *state; + int subsys_id; + u32 idx = 0; + + rcu_read_lock(); + subsys_id = rcu_dereference_index_check(net_prio_subsys_id, + rcu_read_lock_held()); + if (subsys_id >= 0) { + state = container_of(task_subsys_state(p, subsys_id), + struct cgroup_netprio_state, css); + idx = state->prioidx; + } + rcu_read_unlock(); + return idx; } #else +static inline u32 task_netprioidx(struct task_struct *p) +{ + return 0; +} + +#endif /* CONFIG_NETPRIO_CGROUP */ + +#else #define sock_update_netprioidx(sk) #endif diff --git a/net/core/sock.c b/net/core/sock.c index 3e81fd2e3c75..02f8dfe320b7 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1171,13 +1171,10 @@ EXPORT_SYMBOL(sock_update_classid); void sock_update_netprioidx(struct sock *sk) { - struct cgroup_netprio_state *state; if (in_interrupt()) return; - rcu_read_lock(); - state = task_netprio_state(current); - sk->sk_cgrp_prioidx = state ? state->prioidx : 0; - rcu_read_unlock(); + + sk->sk_cgrp_prioidx = task_netprioidx(current); } EXPORT_SYMBOL_GPL(sock_update_netprioidx); #endif -- 2.20.1