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Commit ade9f91b authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds
Browse files

ipc: add missing container_of()s for randstruct 

When building with the randstruct gcc plugin, the layout of the IPC
structs will be randomized, which requires any sub-structure accesses to
use container_of().  The proc display handlers were missing the needed
container_of()s since the iterator is passing in the top-level struct
kern_ipc_perm.

This would lead to crashes when running the "lsipc" program after the
system had IPC registered (e.g. after starting up Gnome):

  general protection fault: 0000 [#1] PREEMPT SMP
  ...
  RIP: 0010:shm_add_rss_swap.isra.1+0x13/0xa0
  ...
  Call Trace:
    sysvipc_shm_proc_show+0x5e/0x150
    sysvipc_proc_show+0x1a/0x30
    seq_read+0x2e9/0x3f0
  ...

Link: http://lkml.kernel.org/r/20170730205950.GA55841@beast


Fixes: 3859a271 ("randstruct: Mark various structs for randomization")
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reported-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Acked-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Acked-by: default avatarManfred Spraul <manfred@colorfullife.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 89affbf5

ipc/msg.c

+2 −1
Original line number Diff line number Diff line
@@ -1034,7 +1034,8 @@ void msg_exit_ns(struct ipc_namespace *ns) 
static int sysvipc_msg_proc_show(struct seq_file *s, void *it)

{

	struct user_namespace *user_ns = seq_user_ns(s);

	struct msg_queue *msq = it;

	struct kern_ipc_perm *ipcp = it;

	struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);



	seq_printf(s,

		   "%10d %10d  %4o  %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",

ipc/sem.c

+2 −1
Original line number Diff line number Diff line
@@ -2179,7 +2179,8 @@ void exit_sem(struct task_struct *tsk) 
static int sysvipc_sem_proc_show(struct seq_file *s, void *it)

{

	struct user_namespace *user_ns = seq_user_ns(s);

	struct sem_array *sma = it;

	struct kern_ipc_perm *ipcp = it;

	struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm);

	time_t sem_otime;



	/*

ipc/shm.c

+3 −1
Original line number Diff line number Diff line
@@ -1380,9 +1380,11 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) 
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)

{

	struct user_namespace *user_ns = seq_user_ns(s);

	struct shmid_kernel *shp = it;

	struct kern_ipc_perm *ipcp = it;

	struct shmid_kernel *shp;

	unsigned long rss = 0, swp = 0;



	shp = container_of(ipcp, struct shmid_kernel, shm_perm);

	shm_add_rss_swap(shp, &rss, &swp);



#if BITS_PER_LONG <= 32