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author | Lu Shuaibing <shuaibinglu@126.com> | 2019-06-20 13:46:16 +1000 |
---|---|---|
committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2019-06-20 13:46:16 +1000 |
commit | e5feb4f77aac5b909e16312172f675e463bc78ed (patch) | |
tree | e4d40f6ba5a30dd848a624086939bfb00828d262 | |
parent | 14a4ee98cf3fcb816b77015ef7c563226cd5f3ea (diff) | |
download | linux-e5feb4f77aac5b909e16312172f675e463bc78ed.tar.gz linux-e5feb4f77aac5b909e16312172f675e463bc78ed.tar.xz |
ipc/msg.c: consolidate all xxxctl_down() functions
A use of uninitialized memory in msgctl_down() because msqid64 in
ksys_msgctl hasn't been initialized. The local | msqid64 | is created in
ksys_msgctl() and then passed into msgctl_down(). Along the way msqid64
is never initialized before msgctl_down() checks msqid64->msg_qbytes.
KUMSAN(KernelUninitializedMemorySantizer, a new error detection tool)
reports:
==================================================================
BUG: KUMSAN: use of uninitialized memory in msgctl_down+0x94/0x300
Read of size 8 at addr ffff88806bb97eb8 by task syz-executor707/2022
CPU: 0 PID: 2022 Comm: syz-executor707 Not tainted 5.2.0-rc4+ #63
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
dump_stack+0x75/0xae
__kumsan_report+0x17c/0x3e6
kumsan_report+0xe/0x20
msgctl_down+0x94/0x300
ksys_msgctl.constprop.14+0xef/0x260
do_syscall_64+0x7e/0x1f0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4400e9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd869e0598 EFLAGS: 00000246 ORIG_RAX: 0000000000000047
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400e9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000401970
R13: 0000000000401a00 R14: 0000000000000000 R15: 0000000000000000
The buggy address belongs to the page:
page:ffffea0001aee5c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x100000000000000()
raw: 0100000000000000 0000000000000000 ffffffff01ae0101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kumsan: bad access detected
==================================================================
Syzkaller reproducer:
msgctl$IPC_RMID(0x0, 0x0)
C reproducer:
// autogenerated by syzkaller (https://github.com/google/syzkaller)
int main(void)
{
syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
syscall(__NR_msgctl, 0, 0, 0);
return 0;
}
Link: http://lkml.kernel.org/r/20190613014044.24234-1-shuaibinglu@126.com
Signed-off-by: Lu Shuaibing <shuaibinglu@126.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: NeilBrown <neilb@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
-rw-r--r-- | ipc/msg.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/ipc/msg.c b/ipc/msg.c index 8dec945fa030..3fe7400b9c43 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -377,7 +377,7 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) * NOTE: no locks must be held, the rwsem is taken inside this function. */ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, - struct msqid64_ds *msqid64) + struct ipc64_perm *perm, int msg_qbytes) { struct kern_ipc_perm *ipcp; struct msg_queue *msq; @@ -387,7 +387,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, rcu_read_lock(); ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd, - &msqid64->msg_perm, msqid64->msg_qbytes); + perm, msg_qbytes); if (IS_ERR(ipcp)) { err = PTR_ERR(ipcp); goto out_unlock1; @@ -409,18 +409,18 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, { DEFINE_WAKE_Q(wake_q); - if (msqid64->msg_qbytes > ns->msg_ctlmnb && + if (msg_qbytes > ns->msg_ctlmnb && !capable(CAP_SYS_RESOURCE)) { err = -EPERM; goto out_unlock1; } ipc_lock_object(&msq->q_perm); - err = ipc_update_perm(&msqid64->msg_perm, ipcp); + err = ipc_update_perm(perm, ipcp); if (err) goto out_unlock0; - msq->q_qbytes = msqid64->msg_qbytes; + msq->q_qbytes = msg_qbytes; msq->q_ctime = ktime_get_real_seconds(); /* @@ -601,9 +601,9 @@ static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int ver case IPC_SET: if (copy_msqid_from_user(&msqid64, buf, version)) return -EFAULT; - /* fallthru */ + return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes); case IPC_RMID: - return msgctl_down(ns, msqid, cmd, &msqid64); + return msgctl_down(ns, msqid, cmd, NULL, 0); default: return -EINVAL; } @@ -735,9 +735,9 @@ static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int versio case IPC_SET: if (copy_compat_msqid_from_user(&msqid64, uptr, version)) return -EFAULT; - /* fallthru */ + return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes); case IPC_RMID: - return msgctl_down(ns, msqid, cmd, &msqid64); + return msgctl_down(ns, msqid, cmd, NULL, 0); default: return -EINVAL; } |