Skip to main content

Browse the archive

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
mc6821.h 
#ifndef _MC6821_H_
#define _MC6821_H_

/*
 * This file describes the memery mapping of the MC6821 PIA.
 * The unions describe overlayed registers. Which of them is used is
 * determined by bit 2 of the corresponding control register.
 * this files expects the PIA_REG_PADWIDTH to be defined the numeric
 * value of the register spacing.
 *
 * Data came from MFC-31-Developer Kit (from Ralph Seidel,
 * zodiac@darkness.gun.de) and Motorola Data Sheet (from 
 * Richard Hirst, srh@gpt.co.uk)
 *
 * 6.11.95 copyright Joerg Dorchain (dorchain@mpi-sb.mpg.de)
 *
 */

#ifndef PIA_REG_PADWIDTH
#define PIA_REG_PADWIDTH 255
#endif

struct pia {
	union {
		volatile u_char pra;
		volatile u_char ddra;
	} ua;
	u_char pad1[PIA_REG_PADWIDTH];
	volatile u_char cra;
	u_char pad2[PIA_REG_PADWIDTH];
	union {
		volatile u_char prb;
		volatile u_char ddrb;
	} ub;
	u_char pad3[PIA_REG_PADWIDTH];
	volatile u_char crb;
	u_char pad4[PIA_REG_PADWIDTH];
};

#define ppra ua.pra
#define pddra ua.ddra
#define pprb ub.prb
#define pddrb ub.ddrb

#define PIA_C1_ENABLE_IRQ (1<<0)
#define PIA_C1_LOW_TO_HIGH (1<<1)
#define PIA_DDR (1<<2)
#define PIA_IRQ2 (1<<6)
#define PIA_IRQ1 (1<<7)

#endif
back to top