From ade9f91b32b964e83d294f4973d50083b08ef6fc Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 2 Aug 2017 13:32:21 -0700 Subject: [PATCH] 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: 3859a271a003 ("randstruct: Mark various structs for randomization") Signed-off-by: Kees Cook Reported-by: Dominik Brodowski Acked-by: Davidlohr Bueso Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/msg.c | 3 ++- ipc/sem.c | 3 ++- ipc/shm.c | 4 +++- 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/ipc/msg.c b/ipc/msg.c index 5b25e0755656..2c38f10d1483 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -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", diff --git a/ipc/sem.c b/ipc/sem.c index 9e70cd7a17da..38371e93bfa5 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -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; /* diff --git a/ipc/shm.c b/ipc/shm.c index 28a444861a8f..8828b4c3a190 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -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 -- 2.20.1