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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
smc91x.h 
#ifndef __SMC91X_H__
#define __SMC91X_H__

/*
 * These bits define which access sizes a platform can support, rather
 * than the maximal access size.  So, if your platform can do 16-bit
 * and 32-bit accesses to the SMC91x device, but not 8-bit, set both
 * SMC91X_USE_16BIT and SMC91X_USE_32BIT.
 *
 * The SMC91x driver requires at least one of SMC91X_USE_8BIT or
 * SMC91X_USE_16BIT to be supported - just setting SMC91X_USE_32BIT is
 * an invalid configuration.
 */
#define SMC91X_USE_8BIT (1 << 0)
#define SMC91X_USE_16BIT (1 << 1)
#define SMC91X_USE_32BIT (1 << 2)

#define SMC91X_NOWAIT		(1 << 3)

/* two bits for IO_SHIFT, let's hope later designs will keep this sane */
#define SMC91X_IO_SHIFT_0	(0 << 4)
#define SMC91X_IO_SHIFT_1	(1 << 4)
#define SMC91X_IO_SHIFT_2	(2 << 4)
#define SMC91X_IO_SHIFT_3	(3 << 4)
#define SMC91X_IO_SHIFT(x)	(((x) >> 4) & 0x3)

#define SMC91X_USE_DMA		(1 << 6)

#define RPC_LED_100_10	(0x00)	/* LED = 100Mbps OR's with 10Mbps link detect */
#define RPC_LED_RES	(0x01)	/* LED = Reserved */
#define RPC_LED_10	(0x02)	/* LED = 10Mbps link detect */
#define RPC_LED_FD	(0x03)	/* LED = Full Duplex Mode */
#define RPC_LED_TX_RX	(0x04)	/* LED = TX or RX packet occurred */
#define RPC_LED_100	(0x05)	/* LED = 100Mbps link detect */
#define RPC_LED_TX	(0x06)	/* LED = TX packet occurred */
#define RPC_LED_RX	(0x07)	/* LED = RX packet occurred */

struct smc91x_platdata {
	unsigned long flags;
	unsigned char leda;
	unsigned char ledb;
	bool pxa_u16_align4;	/* PXA buggy u16 writes on 4*n+2 addresses */
};

#endif /* __SMC91X_H__ */
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