| From 3b2710824e00d238554c13b5add347e6c701ab1a Mon Sep 17 00:00:00 2001 |
| From: Namhyung Kim <namhyung@gmail.com> |
| Date: Sat, 28 May 2011 14:44:46 +0200 |
| Subject: nbd: limit module parameters to a sane value |
| |
| From: Namhyung Kim <namhyung@gmail.com> |
| |
| commit 3b2710824e00d238554c13b5add347e6c701ab1a upstream. |
| |
| The 'max_part' parameter controls the number of maximum partition |
| a nbd device can have. However if a user specifies very large |
| value it would exceed the limitation of device minor number and |
| can cause a kernel oops (or, at least, produce invalid device |
| nodes in some cases). |
| |
| In addition, specifying large 'nbds_max' value causes same |
| problem for the same reason. |
| |
| On my desktop, following command results to the kernel bug: |
| |
| $ sudo modprobe nbd max_part=100000 |
| kernel BUG at /media/Linux_Data/project/linux/fs/sysfs/group.c:65! |
| invalid opcode: 0000 [#1] SMP |
| last sysfs file: /sys/devices/virtual/block/nbd4/range |
| CPU 1 |
| Modules linked in: nbd(+) bridge stp llc kvm_intel kvm asus_atk0110 sg sr_mod cdrom |
| |
| Pid: 2522, comm: modprobe Tainted: G W 2.6.39-leonard+ #159 System manufacturer System Product Name/P5G41TD-M PRO |
| RIP: 0010:[<ffffffff8115aa08>] [<ffffffff8115aa08>] internal_create_group+0x2f/0x166 |
| RSP: 0018:ffff8801009f1de8 EFLAGS: 00010246 |
| RAX: 00000000ffffffef RBX: ffff880103920478 RCX: 00000000000a7bd3 |
| RDX: ffffffff81a2dbe0 RSI: 0000000000000000 RDI: ffff880103920478 |
| RBP: ffff8801009f1e38 R08: ffff880103920468 R09: ffff880103920478 |
| R10: ffff8801009f1de8 R11: ffff88011eccbb68 R12: ffffffff81a2dbe0 |
| R13: ffff880103920468 R14: 0000000000000000 R15: ffff880103920400 |
| FS: 00007f3c49de9700(0000) GS:ffff88011f800000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b |
| CR2: 00007f3b7fe7c000 CR3: 00000000cd58d000 CR4: 00000000000406e0 |
| DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 |
| DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 |
| Process modprobe (pid: 2522, threadinfo ffff8801009f0000, task ffff8801009a93a0) |
| Stack: |
| ffff8801009f1e58 ffffffff812e8f6e ffff8801009f1e58 ffffffff812e7a80 |
| ffff880000000010 ffff880103920400 ffff8801002fd0c0 ffff880103920468 |
| 0000000000000011 ffff880103920400 ffff8801009f1e48 ffffffff8115ab6a |
| Call Trace: |
| [<ffffffff812e8f6e>] ? device_add+0x4f1/0x5e4 |
| [<ffffffff812e7a80>] ? dev_set_name+0x41/0x43 |
| [<ffffffff8115ab6a>] sysfs_create_group+0x13/0x15 |
| [<ffffffff810b857e>] blk_trace_init_sysfs+0x14/0x16 |
| [<ffffffff811ee58b>] blk_register_queue+0x4c/0xfd |
| [<ffffffff811f3bdf>] add_disk+0xe4/0x29c |
| [<ffffffffa007e2ab>] nbd_init+0x2ab/0x30d [nbd] |
| [<ffffffffa007e000>] ? 0xffffffffa007dfff |
| [<ffffffff8100020f>] do_one_initcall+0x7f/0x13e |
| [<ffffffff8107ab0a>] sys_init_module+0xa1/0x1e3 |
| [<ffffffff814f3542>] system_call_fastpath+0x16/0x1b |
| Code: 41 57 41 56 41 55 41 54 53 48 83 ec 28 0f 1f 44 00 00 48 89 fb 41 89 f6 49 89 d4 48 85 ff 74 0b 85 f6 75 0b 48 83 |
| 7f 30 00 75 14 <0f> 0b eb fe b9 ea ff ff ff 48 83 7f 30 00 0f 84 09 01 00 00 49 |
| RIP [<ffffffff8115aa08>] internal_create_group+0x2f/0x166 |
| RSP <ffff8801009f1de8> |
| ---[ end trace 753285ffbf72c57c ]--- |
| |
| Signed-off-by: Namhyung Kim <namhyung@gmail.com> |
| Cc: Laurent Vivier <Laurent.Vivier@bull.net> |
| Cc: Paul Clements <Paul.Clements@steeleye.com> |
| Signed-off-by: Jens Axboe <jaxboe@fusionio.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/block/nbd.c | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| --- a/drivers/block/nbd.c |
| +++ b/drivers/block/nbd.c |
| @@ -754,6 +754,12 @@ static int __init nbd_init(void) |
| if (max_part > 0) |
| part_shift = fls(max_part); |
| |
| + if ((1UL << part_shift) > DISK_MAX_PARTS) |
| + return -EINVAL; |
| + |
| + if (nbds_max > 1UL << (MINORBITS - part_shift)) |
| + return -EINVAL; |
| + |
| for (i = 0; i < nbds_max; i++) { |
| struct gendisk *disk = alloc_disk(1 << part_shift); |
| if (!disk) |