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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
scx200_gpio.h 
u32 scx200_gpio_configure(unsigned index, u32 set, u32 clear);

extern unsigned scx200_gpio_base;
extern unsigned long scx200_gpio_shadow[2];
extern struct nsc_gpio_ops scx200_gpio_ops;

#define scx200_gpio_present() (scx200_gpio_base!=0)

/* Definitions to make sure I do the same thing in all functions */
#define __SCx200_GPIO_BANK unsigned bank = index>>5
#define __SCx200_GPIO_IOADDR unsigned short ioaddr = scx200_gpio_base+0x10*bank
#define __SCx200_GPIO_SHADOW unsigned long *shadow = scx200_gpio_shadow+bank
#define __SCx200_GPIO_INDEX index &= 31

#define __SCx200_GPIO_OUT __asm__ __volatile__("outsl":"=mS" (shadow):"d" (ioaddr), "0" (shadow))

/* returns the value of the GPIO pin */

static inline int scx200_gpio_get(unsigned index) {
	__SCx200_GPIO_BANK;
	__SCx200_GPIO_IOADDR + 0x04;
	__SCx200_GPIO_INDEX;
		
	return (inl(ioaddr) & (1<<index)) ? 1 : 0;
}

/* return the value driven on the GPIO signal (the value that will be
   driven if the GPIO is configured as an output, it might not be the
   state of the GPIO right now if the GPIO is configured as an input) */

static inline int scx200_gpio_current(unsigned index) {
        __SCx200_GPIO_BANK;
	__SCx200_GPIO_INDEX;
		
	return (scx200_gpio_shadow[bank] & (1<<index)) ? 1 : 0;
}

/* drive the GPIO signal high */

static inline void scx200_gpio_set_high(unsigned index) {
	__SCx200_GPIO_BANK;
	__SCx200_GPIO_IOADDR;
	__SCx200_GPIO_SHADOW;
	__SCx200_GPIO_INDEX;
	set_bit(index, shadow);	/* __set_bit()? */
	__SCx200_GPIO_OUT;
}

/* drive the GPIO signal low */

static inline void scx200_gpio_set_low(unsigned index) {
	__SCx200_GPIO_BANK;
	__SCx200_GPIO_IOADDR;
	__SCx200_GPIO_SHADOW;
	__SCx200_GPIO_INDEX;
	clear_bit(index, shadow); /* __clear_bit()? */
	__SCx200_GPIO_OUT;
}

/* drive the GPIO signal to state */

static inline void scx200_gpio_set(unsigned index, int state) {
	__SCx200_GPIO_BANK;
	__SCx200_GPIO_IOADDR;
	__SCx200_GPIO_SHADOW;
	__SCx200_GPIO_INDEX;
	if (state)
		set_bit(index, shadow);
	else
		clear_bit(index, shadow);
	__SCx200_GPIO_OUT;
}

/* toggle the GPIO signal */
static inline void scx200_gpio_change(unsigned index) {
	__SCx200_GPIO_BANK;
	__SCx200_GPIO_IOADDR;
	__SCx200_GPIO_SHADOW;
	__SCx200_GPIO_INDEX;
	change_bit(index, shadow);
	__SCx200_GPIO_OUT;
}

#undef __SCx200_GPIO_BANK
#undef __SCx200_GPIO_IOADDR
#undef __SCx200_GPIO_SHADOW
#undef __SCx200_GPIO_INDEX
#undef __SCx200_GPIO_OUT
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