kernel/linux.git, branch v4.9.148

Linux 4.9.148

2018-12-29T12:40:16+00:00

drm/ioctl: Fix Spectre v1 vulnerabilities

2018-12-29T12:40:16+00:00

commit 505b5240329b922f21f91d5b5d1e535c805eca6d upstream. nr is 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/gpu/drm/drm_ioctl.c:805 drm_ioctl() warn: potential spectre issue 'dev->driver->ioctls' [r] drivers/gpu/drm/drm_ioctl.c:810 drm_ioctl() warn: potential spectre issue 'drm_ioctls' [r] (local cap) drivers/gpu/drm/drm_ioctl.c:892 drm_ioctl_flags() warn: potential spectre issue 'drm_ioctls' [r] (local cap) Fix this by sanitizing nr before using it to index dev->driver->ioctls and drm_ioctls. 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 Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20181220000015.GA18973@embeddedor Signed-off-by: Greg Kroah-Hartman

proc/sysctl: don't return ENOMEM on lookup when a table is unregistering

2018-12-29T12:40:16+00:00

commit ea5751ccd665a2fd1b24f9af81f6167f0718c5f6 upstream. proc_sys_lookup can fail with ENOMEM instead of ENOENT when the corresponding sysctl table is being unregistered. In our case we see this upon opening /proc/sys/net/*/conf files while network interfaces are being deleted, which confuses our configuration daemon. The problem was successfully reproduced and this fix tested on v4.9.122 and v4.20-rc6. v2: return ERR_PTRs in all cases when proc_sys_make_inode fails instead of mixing them with NULL. Thanks Al Viro for the feedback. Fixes: ace0c791e6c3 ("proc/sysctl: Don't grab i_lock under sysctl_lock.") Cc: stable@vger.kernel.org Signed-off-by: Ivan Delalande Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

panic: avoid deadlocks in re-entrant console drivers

2018-12-29T12:40:16+00:00

commit c7c3f05e341a9a2bd1a92993d4f996cfd6e7348e upstream. From printk()/serial console point of view panic() is special, because it may force CPU to re-enter printk() or/and serial console driver. Therefore, some of serial consoles drivers are re-entrant. E.g. 8250: serial8250_console_write() { if (port->sysrq) locked = 0; else if (oops_in_progress) locked = spin_trylock_irqsave(&port->lock, flags); else spin_lock_irqsave(&port->lock, flags); ... } panic() does set oops_in_progress via bust_spinlocks(1), so in theory we should be able to re-enter serial console driver from panic(): CPU0 uart_console_write() serial8250_console_write() // if (oops_in_progress) // spin_trylock_irqsave() call_console_drivers() console_unlock() console_flush_on_panic() bust_spinlocks(1) // oops_in_progress++ panic() spin_lock_irqsave(&port->lock, flags) // spin_lock_irqsave() serial8250_console_write() call_console_drivers() console_unlock() printk() ... However, this does not happen and we deadlock in serial console on port->lock spinlock. And the problem is that console_flush_on_panic() called after bust_spinlocks(0): void panic(const char *fmt, ...) { bust_spinlocks(1); ... bust_spinlocks(0); console_flush_on_panic(); ... } bust_spinlocks(0) decrements oops_in_progress, so oops_in_progress can go back to zero. Thus even re-entrant console drivers will simply spin on port->lock spinlock. Given that port->lock may already be locked either by a stopped CPU, or by the very same CPU we execute panic() on (for instance, NMI panic() on printing CPU) the system deadlocks and does not reboot. Fix this by removing bust_spinlocks(0), so oops_in_progress is always set in panic() now and, thus, re-entrant console drivers will trylock the port->lock instead of spinning on it forever, when we call them from console_flush_on_panic(). Link: http://lkml.kernel.org/r/20181025101036.6823-1-sergey.senozhatsky@gmail.com Cc: Steven Rostedt Cc: Daniel Wang Cc: Peter Zijlstra Cc: Andrew Morton Cc: Linus Torvalds Cc: Greg Kroah-Hartman Cc: Alan Cox Cc: Jiri Slaby Cc: Peter Feiner Cc: linux-serial@vger.kernel.org Cc: Sergey Senozhatsky Cc: stable@vger.kernel.org Signed-off-by: Sergey Senozhatsky Signed-off-by: Petr Mladek Signed-off-by: Greg Kroah-Hartman

ubifs: Handle re-linking of inodes correctly while recovery

2018-12-29T12:40:16+00:00

commit e58725d51fa8da9133f3f1c54170aa2e43056b91 upstream. UBIFS's recovery code strictly assumes that a deleted inode will never come back, therefore it removes all data which belongs to that inode as soon it faces an inode with link count 0 in the replay list. Before O_TMPFILE this assumption was perfectly fine. With O_TMPFILE it can lead to data loss upon a power-cut. Consider a journal with entries like: 0: inode X (nlink = 0) /* O_TMPFILE was created */ 1: data for inode X /* Someone writes to the temp file */ 2: inode X (nlink = 0) /* inode was changed, xattr, chmod, … */ 3: inode X (nlink = 1) /* inode was re-linked via linkat() */ Upon replay of entry #2 UBIFS will drop all data that belongs to inode X, this will lead to an empty file after mounting. As solution for this problem, scan the replay list for a re-link entry before dropping data. Fixes: 474b93704f32 ("ubifs: Implement O_TMPFILE") Cc: stable@vger.kernel.org # 4.9-4.18 Cc: Russell Senior Cc: Rafał Miłecki Reported-by: Russell Senior Reported-by: Rafał Miłecki Tested-by: Rafał Miłecki Signed-off-by: Richard Weinberger [rmilecki: update ubifs_assert() calls to compile with 4.18 and older] Signed-off-by: Rafał Miłecki (cherry picked from commit e58725d51fa8da9133f3f1c54170aa2e43056b91) Signed-off-by: Sasha Levin

x86/fpu: Disable bottom halves while loading FPU registers

2018-12-29T12:40:15+00:00

commit 68239654acafe6aad5a3c1dc7237e60accfebc03 upstream. The sequence fpu->initialized = 1; /* step A */ preempt_disable(); /* step B */ fpu__restore(fpu); preempt_enable(); in __fpu__restore_sig() is racy in regard to a context switch. For 32bit frames, __fpu__restore_sig() prepares the FPU state within fpu->state. To ensure that a context switch (switch_fpu_prepare() in particular) does not modify fpu->state it uses fpu__drop() which sets fpu->initialized to 0. After fpu->initialized is cleared, the CPU's FPU state is not saved to fpu->state during a context switch. The new state is loaded via fpu__restore(). It gets loaded into fpu->state from userland and ensured it is sane. fpu->initialized is then set to 1 in order to avoid fpu__initialize() doing anything (overwrite the new state) which is part of fpu__restore(). A context switch between step A and B above would save CPU's current FPU registers to fpu->state and overwrite the newly prepared state. This looks like a tiny race window but the Kernel Test Robot reported this back in 2016 while we had lazy FPU support. Borislav Petkov made the link between that report and another patch that has been posted. Since the removal of the lazy FPU support, this race goes unnoticed because the warning has been removed. Disable bottom halves around the restore sequence to avoid the race. BH need to be disabled because BH is allowed to run (even with preemption disabled) and might invoke kernel_fpu_begin() by doing IPsec. [ bp: massage commit message a bit. ] Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Borislav Petkov Acked-by: Ingo Molnar Acked-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: "Jason A. Donenfeld" Cc: kvm ML Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Rik van Riel Cc: stable@vger.kernel.org Cc: x86-ml Link: http://lkml.kernel.org/r/20181120102635.ddv3fvavxajjlfqk@linutronix.de Link: https://lkml.kernel.org/r/20160226074940.GA28911@pd.tnic Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman

x86/mtrr: Don't copy uninitialized gentry fields back to userspace

2018-12-29T12:40:15+00:00

commit 32043fa065b51e0b1433e48d118821c71b5cd65d upstream. Currently the copy_to_user of data in the gentry struct is copying uninitiaized data in field _pad from the stack to userspace. Fix this by explicitly memset'ing gentry to zero, this also will zero any compiler added padding fields that may be in struct (currently there are none). Detected by CoverityScan, CID#200783 ("Uninitialized scalar variable") Fixes: b263b31e8ad6 ("x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls") Signed-off-by: Colin Ian King Signed-off-by: Thomas Gleixner Reviewed-by: Tyler Hicks Cc: security@kernel.org Link: https://lkml.kernel.org/r/20181218172956.1440-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: Return -EINVAL for the sys files for unopened channels

2018-12-29T12:40:15+00:00

commit fc96df16a1ce80cbb3c316ab7d4dc8cd5c2852ce upstream. Before 98f4c651762c, we returned zeros for unopened channels. With 98f4c651762c, we started to return random on-stack values. We'd better return -EINVAL instead. Fixes: 98f4c651762c ("hv: move ringbuffer bus attributes to dev_groups") Cc: stable@vger.kernel.org Cc: K. Y. Srinivasan Cc: Haiyang Zhang Cc: Stephen Hemminger Signed-off-by: Dexuan Cui Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

gpio: max7301: fix driver for use with CONFIG_VMAP_STACK

2018-12-29T12:40:15+00:00

commit abf221d2f51b8ce7b9959a8953f880a8b0a1400d upstream. spi_read() and spi_write() require DMA-safe memory. When CONFIG_VMAP_STACK is selected, those functions cannot be used with buffers on stack. This patch replaces calls to spi_read() and spi_write() by spi_write_then_read() which doesn't require DMA-safe buffers. Fixes: 0c36ec314735 ("gpio: gpio driver for max7301 SPI GPIO expander") Cc: Signed-off-by: Christophe Leroy Signed-off-by: Linus Walleij Signed-off-by: Greg Kroah-Hartman

mmc: omap_hsmmc: fix DMA API warning

2018-12-29T12:40:15+00:00

commit 0b479790684192ab7024ce6a621f93f6d0a64d92 upstream. While booting with rootfs on MMC, the following warning is encountered on OMAP4430: omap-dma-engine 4a056000.dma-controller: DMA-API: mapping sg segment longer than device claims to support [len=69632] [max=65536] This is because the DMA engine has a default maximum segment size of 64K but HSMMC sets: mmc->max_blk_size = 512; /* Block Length at max can be 1024 */ mmc->max_blk_count = 0xFFFF; /* No. of Blocks is 16 bits */ mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count; mmc->max_seg_size = mmc->max_req_size; which ends up telling the block layer that we support a maximum segment size of 65535*512, which exceeds the advertised DMA engine capabilities. Fix this by clamping the maximum segment size to the lower of the maximum request size and of the DMA engine device used for either DMA channel. Signed-off-by: Russell King Cc: Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman