From: syzbot <syzbot+17a8efdf800000@syzkaller.appspotmail.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: glider@google.com, gregkh@linuxfoundation.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 4.17 16/46] vt: prevent leaking uninitialized data to userspace via /dev/vcs*
Date: Thu, 05 Jul 2018 22:49:19 -0700 [thread overview]
Message-ID: <0000000000009d986105704e3979@google.com> (raw)
In-Reply-To: <20180706054525.376507928@linuxfoundation.org>
> 4.17-stable review patch. If anyone has any objections, please let me
> know.
> ------------------
> From: Alexander Potapenko <glider@google.com>
> commit 21eff69aaaa0e766ca0ce445b477698dc6a9f55a upstream.
> KMSAN reported an infoleak when reading from /dev/vcs*:
> BUG: KMSAN: kernel-infoleak in vcs_read+0x18ba/0x1cc0
> Call Trace:
> ...
> kmsan_copy_to_user+0x7a/0x160 mm/kmsan/kmsan.c:1253
> copy_to_user ./include/linux/uaccess.h:184
> vcs_read+0x18ba/0x1cc0 drivers/tty/vt/vc_screen.c:352
> __vfs_read+0x1b2/0x9d0 fs/read_write.c:416
> vfs_read+0x36c/0x6b0 fs/read_write.c:452
> ...
> Uninit was created at:
> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279
> kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:189
> kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:315
> __kmalloc+0x13a/0x350 mm/slub.c:3818
> kmalloc ./include/linux/slab.h:517
> vc_allocate+0x438/0x800 drivers/tty/vt/vt.c:787
> con_install+0x8c/0x640 drivers/tty/vt/vt.c:2880
> tty_driver_install_tty drivers/tty/tty_io.c:1224
> tty_init_dev+0x1b5/0x1020 drivers/tty/tty_io.c:1324
> tty_open_by_driver drivers/tty/tty_io.c:1959
> tty_open+0x17b4/0x2ed0 drivers/tty/tty_io.c:2007
> chrdev_open+0xc25/0xd90 fs/char_dev.c:417
> do_dentry_open+0xccc/0x1440 fs/open.c:794
> vfs_open+0x1b6/0x2f0 fs/open.c:908
> ...
> Bytes 0-79 of 240 are uninitialized
> Consistently allocating |vc_screenbuf| with kzalloc() fixes the problem
> Reported-by: syzbot+17a8efdf800000@syzkaller.appspotmail.com
> Signed-off-by: Alexander Potapenko <glider@google.com>
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> drivers/tty/vt/vt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
> --- a/drivers/tty/vt/vt.c
> +++ b/drivers/tty/vt/vt.c
> @@ -784,7 +784,7 @@ int vc_allocate(unsigned int currcons) /
> if (!*vc->vc_uni_pagedir_loc)
> con_set_default_unimap(vc);
> - vc->vc_screenbuf = kmalloc(vc->vc_screenbuf_size, GFP_KERNEL);
> + vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
> if (!vc->vc_screenbuf)
> goto err_free;
> @@ -871,7 +871,7 @@ static int vc_do_resize(struct tty_struc
> if (new_screen_size > (4 << 20))
> return -EINVAL;
> - newscreen = kmalloc(new_screen_size, GFP_USER);
> + newscreen = kzalloc(new_screen_size, GFP_USER);
> if (!newscreen)
> return -ENOMEM;
Can't find the corresponding bug.
next prev parent reply other threads:[~2018-07-06 6:08 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 5:46 [PATCH 4.17 00/46] 4.17.5-stable review Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 01/46] usb: cdc_acm: Add quirk for Uniden UBC125 scanner Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 02/46] USB: serial: cp210x: add CESINEL device ids Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 03/46] USB: serial: cp210x: add Silicon Labs IDs for Windows Update Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 04/46] usb: dwc2: fix the incorrect bitmaps for the ports of multi_tt hub Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 05/46] usb: typec: tcpm: fix logbuffer index is wrong if _tcpm_log is re-entered Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 06/46] acpi: Add helper for deactivating memory region Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 07/46] usb: typec: ucsi: acpi: Workaround for cache mode issue Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 08/46] usb: typec: ucsi: Fix for incorrect status data issue Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 09/46] xhci: Fix kernel oops in trace_xhci_free_virt_device Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 10/46] n_tty: Fix stall at n_tty_receive_char_special() Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 11/46] n_tty: Access echo_* variables carefully Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 12/46] staging: android: ion: Return an ERR_PTR in ion_map_kernel Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 13/46] iio: mma8452: Fix ignoring MMA8452_INT_DRDY Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 14/46] serial: 8250_pci: Remove stalled entries in blacklist Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 15/46] serdev: fix memleak on module unload Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 16/46] vt: prevent leaking uninitialized data to userspace via /dev/vcs* Greg Kroah-Hartman
2018-07-06 5:49 ` syzbot [this message]
2018-07-06 5:46 ` [PATCH 4.17 22/46] drm/sti: Depend on OF rather than selecting it Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 23/46] drm/amd/display: Clear connectors edid pointer Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 25/46] drm/qxl: Call qxl_bo_unref outside atomic context Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 26/46] drm/atmel-hlcdc: check stride values in the first plane Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 27/46] Revert "drm/sun4i: Handle DRM_BUS_FLAG_PIXDATA_*EDGE" Greg Kroah-Hartman
2018-07-06 5:46 ` [PATCH 4.17 28/46] drm/amdgpu: Dont default to DC support for Kaveri and older Greg Kroah-Hartman
2018-07-06 5:47 ` [PATCH 4.17 40/46] drm/i915: Enable provoking vertex fix on Gen9 systems Greg Kroah-Hartman
2018-07-06 5:47 ` [PATCH 4.17 41/46] netfilter: ip6t_rpfilter: provide input interface for route lookup Greg Kroah-Hartman
2018-07-06 5:47 ` [PATCH 4.17 42/46] netfilter: xt_connmark: fix list corruption on rmmod Greg Kroah-Hartman
2018-07-06 5:47 ` [PATCH 4.17 43/46] netfilter: nf_tables: use WARN_ON_ONCE instead of BUG_ON in nft_do_chain() Greg Kroah-Hartman
2018-07-06 5:47 ` [PATCH 4.17 44/46] ARM64: dts: meson-gxl-s905x-p212: Add phy-supply for usb0 Greg Kroah-Hartman
2018-07-06 5:47 ` [PATCH 4.17 45/46] x86/mm: Dont free P4D table when it is folded at runtime Greg Kroah-Hartman
2018-07-06 5:47 ` [PATCH 4.17 46/46] ARM: dts: imx6q: Use correct SDMA script for SPI5 core Greg Kroah-Hartman
2018-07-06 17:51 ` [PATCH 4.17 00/46] 4.17.5-stable review Dan Rue
2018-07-06 18:09 ` Dan Rue
2018-07-07 14:52 ` Greg Kroah-Hartman
2018-07-07 21:40 ` Guenter Roeck
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