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Revision da094e42848e3c36feaa3b5271e53983fd45424f authored by Prakash Gupta on 18 August 2017, 22:16:21 UTC, committed by Linus Torvalds on 18 August 2017, 22:32:02 UTC 
mm/cma_debug.c: fix stack corruption due to sprintf usage
 
name[] in cma_debugfs_add_one() can only accommodate 16 chars including
NULL to store sprintf output.  It's common for cma device name to be
larger than 15 chars.  This can cause stack corrpution.  If the gcc
stack protector is turned on, this can cause a panic due to stack
corruption.

Below is one example trace:

  Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in:
  ffffff8e69a75730
  Call trace:
     dump_backtrace+0x0/0x2c4
     show_stack+0x20/0x28
     dump_stack+0xb8/0xf4
     panic+0x154/0x2b0
     print_tainted+0x0/0xc0
     cma_debugfs_init+0x274/0x290
     do_one_initcall+0x5c/0x168
     kernel_init_freeable+0x1c8/0x280

Fix the short sprintf buffer in cma_debugfs_add_one() by using
scnprintf() instead of sprintf().

Link: http://lkml.kernel.org/r/1502446217-21840-1-git-send-email-guptap@codeaurora.org
Fixes: f318dd083c81 ("cma: Store a name in the cma structure")
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent eb61b59
Raw File
i7300_idle.h 

#ifndef I7300_IDLE_H
#define I7300_IDLE_H

#include <linux/pci.h>

/*
 * I/O AT controls (PCI bus 0 device 8 function 0)
 * DIMM controls (PCI bus 0 device 16 function 1)
 */
#define IOAT_BUS 0
#define IOAT_DEVFN PCI_DEVFN(8, 0)
#define MEMCTL_BUS 0
#define MEMCTL_DEVFN PCI_DEVFN(16, 1)

struct fbd_ioat {
	unsigned int vendor;
	unsigned int ioat_dev;
	unsigned int enabled;
};

/*
 * The i5000 chip-set has the same hooks as the i7300
 * but it is not enabled by default and must be manually
 * manually enabled with "forceload=1" because it is
 * only lightly validated.
 */

static const struct fbd_ioat fbd_ioat_list[] = {
	{PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_CNB, 1},
	{PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT, 0},
	{0, 0}
};

/* table of devices that work with this driver */
static const struct pci_device_id pci_tbl[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_FBD_CNB) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5000_ERR) },
	{ } /* Terminating entry */
};

/* Check for known platforms with I/O-AT */
static inline int i7300_idle_platform_probe(struct pci_dev **fbd_dev,
						struct pci_dev **ioat_dev,
						int enable_all)
{
	int i;
	struct pci_dev *memdev, *dmadev;

	memdev = pci_get_bus_and_slot(MEMCTL_BUS, MEMCTL_DEVFN);
	if (!memdev)
		return -ENODEV;

	for (i = 0; pci_tbl[i].vendor != 0; i++) {
		if (memdev->vendor == pci_tbl[i].vendor &&
		    memdev->device == pci_tbl[i].device) {
			break;
		}
	}
	if (pci_tbl[i].vendor == 0)
		return -ENODEV;

	dmadev = pci_get_bus_and_slot(IOAT_BUS, IOAT_DEVFN);
	if (!dmadev)
		return -ENODEV;

	for (i = 0; fbd_ioat_list[i].vendor != 0; i++) {
		if (dmadev->vendor == fbd_ioat_list[i].vendor &&
		    dmadev->device == fbd_ioat_list[i].ioat_dev) {
			if (!(fbd_ioat_list[i].enabled || enable_all))
				continue;
			if (fbd_dev)
				*fbd_dev = memdev;
			if (ioat_dev)
				*ioat_dev = dmadev;

			return 0;
		}
	}
	return -ENODEV;
}

#endif
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