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Groups > linux.kernel > #1626219

[PATCH 4.10 69/69] virtio-console: avoid DMA from stack

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 4.10 69/69] virtio-console: avoid DMA from stack
Date 2017-04-19 16:50 +0200
Message-ID <txZ5G-4CC-63@gated-at.bofh.it> (permalink)
References <txYVX-4yJ-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Omar Sandoval <osandov@fb.com>

commit c4baad50297d84bde1a7ad45e50c73adae4a2192 upstream.

put_chars() stuffs the buffer it gets into an sg, but that buffer may be
on the stack. This breaks with CONFIG_VMAP_STACK=y (for me, it
manifested as printks getting turned into NUL bytes).

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/char/virtio_console.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1136,6 +1136,8 @@ static int put_chars(u32 vtermno, const
 {
 	struct port *port;
 	struct scatterlist sg[1];
+	void *data;
+	int ret;
 
 	if (unlikely(early_put_chars))
 		return early_put_chars(vtermno, buf, count);
@@ -1144,8 +1146,14 @@ static int put_chars(u32 vtermno, const
 	if (!port)
 		return -EPIPE;
 
-	sg_init_one(sg, buf, count);
-	return __send_to_port(port, sg, 1, count, (void *)buf, false);
+	data = kmemdup(buf, count, GFP_ATOMIC);
+	if (!data)
+		return -ENOMEM;
+
+	sg_init_one(sg, data, count);
+	ret = __send_to_port(port, sg, 1, count, data, false);
+	kfree(data);
+	return ret;
 }
 
 /*

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[PATCH 4.10 00/69] 4.10.12-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 18/69] CIFS: store results of cifs_reopen_file to avoid infinite wait Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 20/69] perf annotate s390: Fix perf annotate error -95 (4.10 regression) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 48/69] cpufreq: Bring CPUs up even if cpufreq_online() failed Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 35/69] scsi: sr: Sanity check returned mode data Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 15/69] drm/etnaviv: fix missing unlock on error in etnaviv_gpu_submit() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 08/69] zsmalloc: expand class bit Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 11/69] drm/nouveau/mmu/nv4a: use nv04 mmu rather than the nv44 one Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 26/69] x86/vdso: Ensure vdso32_enabled gets set to valid values only Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200
  [PATCH 4.10 42/69] make skb_copy_datagram_msg() et.al. preserve ->msg_iter on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 67/69] mm: Tighten x86 /dev/mem with zeroing reads Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 39/69] target: Avoid mappedlun symlink creation during lun shutdown Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 52/69] char: lack of bool string made CONFIG_DEVPORT always on Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 34/69] iscsi-target: Drop work-around for legacy GlobalSAN initiator Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 43/69] libnvdimm: fix blk free space accounting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 40/69] xen, fbfront: fix connecting to backend Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 69/69] virtio-console: avoid DMA from stack Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 65/69] ACPI / EC: Use busy polling mode when GPE is not enabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 66/69] rtc: tegra: Implement clock handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 41/69] [iov_iter] new privimitive: iov_iter_revert() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 37/69] scsi: qla2xxx: Add fix to read correct register value for ISP82xx. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:50 +0200
  [PATCH 4.10 56/69] crypto: algif_aead - Fix bogus request dereference in completion function Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 54/69] zram: do not use copy_page with non-page aligned address Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 58/69] crypto: ahash - Fix EINPROGRESS notification callback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 61/69] [media] dvb-usb-v2: avoid use-after-free Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 36/69] scsi: sd: Consider max_xfer_blocks if opt_xfer_blocks is unusable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 59/69] crypto: lrw - Fix use-after-free on EINPROGRESS Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 38/69] scsi: sd: Fix capacity calculation with 32-bit sector_t Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 57/69] crypto: xts - Fix use-after-free on EINPROGRESS Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 64/69] x86/xen: Fix APIC id mismatch warning on Intel Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 62/69] ASoC: Intel: select DW_DMAC_CORE since its mandatory Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:20 +0200
  [PATCH 4.10 55/69] ftrace: Fix function pid filter on instances Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 06/69] thp: fix MADV_DONTNEED vs. MADV_FREE race Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 23/69] x86/signals: Fix lower/upper bound reporting in compat siginfo Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 45/69] libnvdimm: band aid btt vs clear poison locking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 07/69] thp: fix MADV_DONTNEED vs clear soft dirty race Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 50/69] ftrace: Fix removing of second function probe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 49/69] irqchip/irq-imx-gpcv2: Fix spinlock initialization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 51/69] drm/i915/gvt: set the correct default value of CTX STATUS PTR Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 46/69] can: ifi: use correct register to read rx status Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 31/69] efi/libstub: Skip GOP with PIXEL_BLT_ONLY format Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 22/69] x86/efi: Dont try to reserve runtime regions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 25/69] x86, pmem: fix broken __copy_user_nocache cache-bypass assumptions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 28/69] acpi, nfit, libnvdimm: fix interleave set cookie calculation (64-bit comparison) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 27/69] x86/vdso: Plug race between mapping and ELF header setup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 53/69] Revert "MIPS: Lantiq: Fix cascaded IRQ setup" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 32/69] efi/fb: Avoid reconfiguration of BAR that covers the framebuffer Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 09/69] orangefs: free superblock when mount fails Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 03/69] tcmu: Fix possible overwrite of t_data_sgs last iov[] Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 04/69] tcmu: Fix wrongly calculating of the base_command_size Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 29/69] ACPI / scan: Set the visited flag for all enumerated devices Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 47/69] pwm: rockchip: State of PWM clock should synchronize with PWM enabled state Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 05/69] tcmu: Skip Data-Out blocks before gathering Data-In buffer for BIDI case Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 60/69] parisc: Fix get_user() for 64-bit value on 32-bit kernel Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 44/69] libnvdimm: fix reconfig_mutex, mmap_sem, and jbd2_handle lockdep splat Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:30 +0200
  [PATCH 4.10 19/69] Input: xpad - add support for Razer Wildcat gamepad Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:40 +0200
  [PATCH 4.10 17/69] CIFS: reconnect thread reschedule itself Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:40 +0200
  [PATCH 4.10 13/69] drm/nouveau/kms/nv50: fix double dma_fence_put() when destroying plane state Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:40 +0200
  [PATCH 4.10 02/69] audit: make sure we dont let the retry queue grow without bounds Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:40 +0200
  [PATCH 4.10 01/69] cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:40 +0200
  [PATCH 4.10 10/69] drm/nouveau/mpeg: mthd returns true on success now Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:40 +0200
  [PATCH 4.10 12/69] drm/nouveau/kms/nv50: fix setting of HeadSetRasterVertBlankDmi method Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:40 +0200
  Re: [PATCH 4.10 00/69] 4.10.12-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-04-19 22:40 +0200
    Re: [PATCH 4.10 00/69] 4.10.12-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-20 08:40 +0200
  Re: [PATCH 4.10 00/69] 4.10.12-stable review Guenter Roeck <linux@roeck-us.net> - 2017-04-20 01:30 +0200
    Re: [PATCH 4.10 00/69] 4.10.12-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-20 08:40 +0200

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