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Taehee Yoo c83d7f2add netdevsim: fix using uninitialized resources 
commit f5cd21605e upstream.

When module is being initialized, __init() calls bus_register() and
driver_register().
These functions internally create various resources and sysfs files.
The sysfs files are used for basic operations(add/del device).
/sys/bus/netdevsim/new_device
/sys/bus/netdevsim/del_device

These sysfs files use netdevsim resources, they are mostly allocated
and initialized in ->probe() function, which is nsim_dev_probe().
But, sysfs files could be executed before ->probe() is finished.
So, accessing uninitialized data would occur.

Another problem is very similar.
/sys/bus/netdevsim/new_device internally creates sysfs files.
/sys/devices/netdevsim<id>/new_port
/sys/devices/netdevsim<id>/del_port

These sysfs files also use netdevsim resources, they are mostly allocated
and initialized in creating device routine, which is nsim_bus_dev_new().
But they also could be executed before nsim_bus_dev_new() is finished.
So, accessing uninitialized data would occur.

To fix these problems, this patch adds flags, which means whether the
operation is finished or not.
The flag variable 'nsim_bus_enable' means whether netdevsim bus was
initialized or not.
This is protected by nsim_bus_dev_list_lock.
The flag variable 'nsim_bus_dev->init' means whether nsim_bus_dev was
initialized or not.
This could be used in {new/del}_port_store() with no lock.

Test commands:
    #SHELL1
    modprobe netdevsim
    while :
    do
        echo "1 1" > /sys/bus/netdevsim/new_device
        echo "1 1" > /sys/bus/netdevsim/del_device
    done

    #SHELL2
    while :
    do
        echo 1 > /sys/devices/netdevsim1/new_port
        echo 1 > /sys/devices/netdevsim1/del_port
    done

Splat looks like:
[   47.508954][ T1008] general protection fault, probably for non-canonical address 0xdffffc0000000021: 0000 I
[   47.510793][ T1008] KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f]
[   47.511963][ T1008] CPU: 2 PID: 1008 Comm: bash Not tainted 5.5.0+ #322
[   47.512823][ T1008] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[   47.514041][ T1008] RIP: 0010:__mutex_lock+0x10a/0x14b0
[   47.514699][ T1008] Code: 08 84 d2 0f 85 7f 12 00 00 44 8b 0d 10 23 65 02 45 85 c9 75 29 49 8d 7f 68 48 b8 00 00 00 0f
[   47.517163][ T1008] RSP: 0018:ffff888059b4fbb0 EFLAGS: 00010206
[   47.517802][ T1008] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   47.518941][ T1008] RDX: 0000000000000021 RSI: ffffffff85926440 RDI: 0000000000000108
[   47.519732][ T1008] RBP: ffff888059b4fd30 R08: ffffffffc073fad0 R09: 0000000000000000
[   47.520729][ T1008] R10: ffff888059b4fd50 R11: ffff88804bb38040 R12: 0000000000000000
[   47.521702][ T1008] R13: dffffc0000000000 R14: ffffffff871976c0 R15: 00000000000000a0
[   47.522760][ T1008] FS:  00007fd4be05a740(0000) GS:ffff88806c800000(0000) knlGS:0000000000000000
[   47.523877][ T1008] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   47.524627][ T1008] CR2: 0000561c82b69cf0 CR3: 0000000065dd6004 CR4: 00000000000606e0
[   47.527662][ T1008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   47.528604][ T1008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   47.529531][ T1008] Call Trace:
[   47.529874][ T1008]  ? nsim_dev_port_add+0x50/0x150 [netdevsim]
[   47.530470][ T1008]  ? mutex_lock_io_nested+0x1380/0x1380
[   47.531018][ T1008]  ? _kstrtoull+0x76/0x160
[   47.531449][ T1008]  ? _parse_integer+0xf0/0xf0
[   47.531874][ T1008]  ? kernfs_fop_write+0x1cf/0x410
[   47.532330][ T1008]  ? sysfs_file_ops+0x160/0x160
[   47.532773][ T1008]  ? kstrtouint+0x86/0x110
[   47.533168][ T1008]  ? nsim_dev_port_add+0x50/0x150 [netdevsim]
[   47.533721][ T1008]  nsim_dev_port_add+0x50/0x150 [netdevsim]
[   47.534336][ T1008]  ? sysfs_file_ops+0x160/0x160
[   47.534858][ T1008]  new_port_store+0x99/0xb0 [netdevsim]
[   47.535439][ T1008]  ? del_port_store+0xb0/0xb0 [netdevsim]
[   47.536035][ T1008]  ? sysfs_file_ops+0x112/0x160
[   47.536544][ T1008]  ? sysfs_kf_write+0x3b/0x180
[   47.537029][ T1008]  kernfs_fop_write+0x276/0x410
[   47.537548][ T1008]  ? __sb_start_write+0x215/0x2e0
[   47.538110][ T1008]  vfs_write+0x197/0x4a0
[ ... ]

Fixes: f9d9db47d3 ("netdevsim: add bus attributes to add new and delete devices")
Fixes: 794b2c05ca ("netdevsim: extend device attrs to support port addition and deletion")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2020-02-14 16:53:00 -05:00
arch x86/boot: Handle malformed SRAT tables during early ACPI parsing 2020-02-14 16:52:59 -05:00
block compat: scsi: sg: fix v3 compat read/write interface 2020-02-11 04:37:17 -08:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto crypto: api - Fix race condition in crypto_spawn_alg 2020-02-11 04:37:01 -08:00
Documentation PM / devfreq: Add new name attribute for sysfs 2020-02-04 18:18:01 +00:00
drivers netdevsim: fix using uninitialized resources 2020-02-14 16:53:00 -05:00
fs NFSv4.0: nfs4_do_fsinfo() should not do implicit lease renewals 2020-02-14 16:52:59 -05:00
include RDMA/uverbs: Verify MR access flags 2020-02-14 16:52:56 -05:00
init Revert "um: Enable CONFIG_CONSTRUCTORS" 2020-02-01 09:33:00 +00:00
ipc ipc/msg.c: consolidate all xxxctl_down() functions 2020-02-11 04:36:39 -08:00
kernel perf/cgroups: Install cgroup events to correct cpuctx 2020-02-11 04:37:28 -08:00
lib lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more() 2020-02-11 04:36:45 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush 2020-02-11 04:37:14 -08:00
net bpf, sockmap: Check update requirements after locking 2020-02-14 16:53:00 -05:00
samples samples/bpf: Reintroduce missed build targets 2020-02-11 04:37:00 -08:00
scripts scripts/find-unused-docs: Fix massive false positives 2020-02-11 04:36:53 -08:00
security broken ping to ipv6 linklocal addresses on debian buster 2020-02-11 04:37:16 -08:00
sound ASoC: Intel: skl_hda_dsp_common: Fix global-out-of-bounds bug 2020-02-11 04:37:21 -08:00
tools selftests/bpf: Test freeing sockmap/sockhash with a socket in it 2020-02-14 16:52:59 -05:00
usr gen_initramfs_list.sh: fix 'bad variable name' error 2020-01-04 00:00:48 +09:00
virt KVM: Play nice with read-only memslots when querying host page size 2020-02-11 04:37:29 -08:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap MAINTAINERS: update my email address 2020-01-11 14:33:39 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: correct entries for ISDN/mISDN section 2020-02-11 04:36:38 -08:00
Makefile Linux 5.5.3 2020-02-11 04:37:31 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.