kernel/drivers/usb/gadget/function/f_mass_storage.c, branch linux-5.1.y

Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2018-10-24T10:22:39Z

Pull siginfo updates from Eric Biederman: "I have been slowly sorting out siginfo and this is the culmination of that work. The primary result is in several ways the signal infrastructure has been made less error prone. The code has been updated so that manually specifying SEND_SIG_FORCED is never necessary. The conversion to the new siginfo sending functions is now complete, which makes it difficult to send a signal without filling in the proper siginfo fields. At the tail end of the patchset comes the optimization of decreasing the size of struct siginfo in the kernel from 128 bytes to about 48 bytes on 64bit. The fundamental observation that enables this is by definition none of the known ways to use struct siginfo uses the extra bytes. This comes at the cost of a small user space observable difference. For the rare case of siginfo being injected into the kernel only what can be copied into kernel_siginfo is delivered to the destination, the rest of the bytes are set to 0. For cases where the signal and the si_code are known this is safe, because we know those bytes are not used. For cases where the signal and si_code combination is unknown the bits that won't fit into struct kernel_siginfo are tested to verify they are zero, and the send fails if they are not. I made an extensive search through userspace code and I could not find anything that would break because of the above change. If it turns out I did break something it will take just the revert of a single change to restore kernel_siginfo to the same size as userspace siginfo. Testing did reveal dependencies on preferring the signo passed to sigqueueinfo over si->signo, so bit the bullet and added the complexity necessary to handle that case. Testing also revealed bad things can happen if a negative signal number is passed into the system calls. Something no sane application will do but something a malicious program or a fuzzer might do. So I have fixed the code that performs the bounds checks to ensure negative signal numbers are handled" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits) signal: Guard against negative signal numbers in copy_siginfo_from_user32 signal: Guard against negative signal numbers in copy_siginfo_from_user signal: In sigqueueinfo prefer sig not si_signo signal: Use a smaller struct siginfo in the kernel signal: Distinguish between kernel_siginfo and siginfo signal: Introduce copy_siginfo_from_user and use it's return value signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE signal: Fail sigqueueinfo if si_signo != sig signal/sparc: Move EMT_TAGOVF into the generic siginfo.h signal/unicore32: Use force_sig_fault where appropriate signal/unicore32: Generate siginfo in ucs32_notify_die signal/unicore32: Use send_sig_fault where appropriate signal/arc: Use force_sig_fault where appropriate signal/arc: Push siginfo generation into unhandled_exception signal/ia64: Use force_sig_fault where appropriate signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn signal/ia64: Use the generic force_sigsegv in setup_frame signal/arm/kvm: Use send_sig_mceerr signal/arm: Use send_sig_fault where appropriate signal/arm: Use force_sig_fault where appropriate ...

usb: gadget: storage: Fix Spectre v1 vulnerability

2018-10-17T18:57:55Z

num can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/usb/gadget/function/f_mass_storage.c:3177 fsg_lun_make() warn: potential spectre issue 'fsg_opts->common->luns' [r] (local cap) Fix this by sanitizing num before using it to index fsg_opts->common->luns Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva Acked-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman

signal: Don't send siginfo to kthreads.

2018-09-11T19:19:22Z

Today kernel threads never dequeue siginfo so it is pointless to enqueue siginfo for them. The usb gadget mass storage driver goes one farther and uses SEND_SIG_FORCED to guarantee that no siginfo is even enqueued. Generalize the optimization of the usb mass storage driver and never perform an unnecessary allocation when delivering signals to kthreads. Switch the mass storage driver from sending signals with SEND_SIG_FORCED to SEND_SIG_PRIV. As using SEND_SIG_FORCED is now unnecessary. Reviewed-by: Thomas Gleixner Signed-off-by: "Eric W. Biederman"

signal: Remove the siginfo paramater from kernel_dqueue_signal

2018-09-11T19:19:14Z

None of the callers use the it so remove it. Reviewed-by: Thomas Gleixner Signed-off-by: "Eric W. Biederman"

usb: gadget: storage: Remove reference counting

2018-07-26T10:55:39Z

The kref used to be needed because sharing of fsg_common among multiple USB function instances was handled by fsg. Now this is managed by configfs, we don't need it anymore. So let's eliminate kref from this driver. Acked-by: Alan Stern Acked-by: Michal Nazarewicz Signed-off-by: Jaejoong Kim Signed-off-by: Felipe Balbi

usb: gadget: storage: Add error handling for no memory

2018-07-26T10:55:17Z

fsg_common_set_num_buffers() may fail due to ENOMEM. So add error handling for fail case. Acked-by: Alan Stern Acked-by: Michal Nazarewicz Signed-off-by: Jaejoong Kim Signed-off-by: Felipe Balbi

Merge tag 'configfs-for-4.15' of git://git.infradead.org/users/hch/configfs

2017-11-14T22:44:04Z

Pull configfs updates from Christoph Hellwig: "A couple of configfs cleanups: - proper use of the bool type (Thomas Meyer) - constification of struct config_item_type (Bhumika Goyal)" * tag 'configfs-for-4.15' of git://git.infradead.org/users/hch/configfs: RDMA/cma: make config_item_type const stm class: make config_item_type const ACPI: configfs: make config_item_type const nvmet: make config_item_type const usb: gadget: configfs: make config_item_type const PCI: endpoint: make config_item_type const iio: make function argument and some structures const usb: gadget: make config_item_type structures const dlm: make config_item_type const netconsole: make config_item_type const nullb: make config_item_type const ocfs2/cluster: make config_item_type const target: make config_item_type const configfs: make ci_type field, some pointers and function arguments const configfs: make config_item_type const configfs: Fix bool initialization/comparison

USB: add SPDX identifiers to all remaining files in drivers/usb/

2017-11-04T10:48:02Z

It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/usb/ and include/linux/usb* files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner Cc: Kate Stewart Cc: Philippe Ombredanne Signed-off-by: Greg Kroah-Hartman Acked-by: Felipe Balbi Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

usb: gadget: make config_item_type structures const

2017-10-19T14:15:23Z

Make these structures const as they are only passed to the const argument of the functions config_{group/item}_init_type_name. Signed-off-by: Bhumika Goyal Acked-by: Felipe Balbi Signed-off-by: Christoph Hellwig

USB: g_mass_storage: Fix deadlock when driver is unbound

2017-09-22T16:29:00Z

As a holdover from the old g_file_storage gadget, the g_mass_storage legacy gadget driver attempts to unregister itself when its main operating thread terminates (if it hasn't been unregistered already). This is not strictly necessary; it was never more than an attempt to have the gadget fail cleanly if something went wrong and the main thread was killed. However, now that the UDC core manages gadget drivers independently of UDC drivers, this scheme doesn't work any more. A simple test: modprobe dummy-hcd modprobe g-mass-storage file=... rmmod dummy-hcd ends up in a deadlock with the following backtrace: sysrq: SysRq : Show Blocked State task PC stack pid father file-storage D 0 1130 2 0x00000000 Call Trace: __schedule+0x53e/0x58c schedule+0x6e/0x77 schedule_preempt_disabled+0xd/0xf __mutex_lock.isra.1+0x129/0x224 ? _raw_spin_unlock_irqrestore+0x12/0x14 __mutex_lock_slowpath+0x12/0x14 mutex_lock+0x28/0x2b usb_gadget_unregister_driver+0x29/0x9b [udc_core] usb_composite_unregister+0x10/0x12 [libcomposite] msg_cleanup+0x1d/0x20 [g_mass_storage] msg_thread_exits+0xd/0xdd7 [g_mass_storage] fsg_main_thread+0x1395/0x13d6 [usb_f_mass_storage] ? __schedule+0x573/0x58c kthread+0xd9/0xdb ? do_set_interface+0x25c/0x25c [usb_f_mass_storage] ? init_completion+0x1e/0x1e ret_from_fork+0x19/0x24 rmmod D 0 1155 683 0x00000000 Call Trace: __schedule+0x53e/0x58c schedule+0x6e/0x77 schedule_timeout+0x26/0xbc ? __schedule+0x573/0x58c do_wait_for_common+0xb3/0x128 ? usleep_range+0x81/0x81 ? wake_up_q+0x3f/0x3f wait_for_common+0x2e/0x45 wait_for_completion+0x17/0x19 fsg_common_put+0x34/0x81 [usb_f_mass_storage] fsg_free_inst+0x13/0x1e [usb_f_mass_storage] usb_put_function_instance+0x1a/0x25 [libcomposite] msg_unbind+0x2a/0x42 [g_mass_storage] __composite_unbind+0x4a/0x6f [libcomposite] composite_unbind+0x12/0x14 [libcomposite] usb_gadget_remove_driver+0x4f/0x77 [udc_core] usb_del_gadget_udc+0x52/0xcc [udc_core] dummy_udc_remove+0x27/0x2c [dummy_hcd] platform_drv_remove+0x1d/0x31 device_release_driver_internal+0xe9/0x16d device_release_driver+0x11/0x13 bus_remove_device+0xd2/0xe2 device_del+0x19f/0x221 ? selinux_capable+0x22/0x27 platform_device_del+0x21/0x63 platform_device_unregister+0x10/0x1a cleanup+0x20/0x817 [dummy_hcd] SyS_delete_module+0x10c/0x197 ? ____fput+0xd/0xf ? task_work_run+0x55/0x62 ? prepare_exit_to_usermode+0x65/0x75 do_fast_syscall_32+0x86/0xc3 entry_SYSENTER_32+0x4e/0x7c What happens is that removing the dummy-hcd driver causes the UDC core to unbind the gadget driver, which it does while holding the udc_lock mutex. The unbind routine in g_mass_storage tells the main thread to exit and waits for it to terminate. But as mentioned above, when the main thread exits it tries to unregister the mass-storage function driver. Via the composite framework this ends up calling usb_gadget_unregister_driver(), which tries to acquire the udc_lock mutex. The result is deadlock. The simplest way to fix the problem is not to be so clever: The main thread doesn't have to unregister the function driver. The side effects won't be so terrible; if the gadget is still attached to a USB host when the main thread is killed, it will appear to the host as though the gadget's firmware has crashed -- a reasonably accurate interpretation, and an all-too-common occurrence for USB mass-storage devices. In fact, the code to unregister the driver when the main thread exits is specific to g-mass-storage; it is not used when f-mass-storage is included as a function in a larger composite device. Therefore the entire mechanism responsible for this (the fsg_operations structure with its ->thread_exits method, the fsg_common_set_ops() routine, and the msg_thread_exits() callback routine) can all be eliminated. Even the msg_registered bitflag can be removed, because now the driver is unregistered in only one place rather than in two places. Signed-off-by: Alan Stern CC: Acked-by: Felipe Balbi Acked-by: Michal Nazarewicz Signed-off-by: Greg Kroah-Hartman