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x86/platform/intel-mid: Fix a format string overflow warning 

We have space for exactly three characters for the index in "max7315_%d_base",
but as GCC points out having more would cause an string overflow:

  arch/x86/platform/intel-mid/device_libs/platform_max7315.c: In function 'max7315_platform_data':
  arch/x86/platform/intel-mid/device_libs/platform_max7315.c:41:26: error: '%d' directive writing between 1 and 11 bytes into a region of size 9 [-Werror=format-overflow=]
     sprintf(base_pin_name, "max7315_%d_base", nr);
                          ^~~~~~~~~~~~~~~~~
  arch/x86/platform/intel-mid/device_libs/platform_max7315.c:41:26: note: directive argument in the range [-2147483647, 2147483647]
  arch/x86/platform/intel-mid/device_libs/platform_max7315.c:41:3: note: 'sprintf' output between 15 and 25 bytes into a destination of size 17
     sprintf(base_pin_name, "max7315_%d_base", nr);

This makes it use an snprintf() to truncate the string if that happened
rather than overflowing the stack. In practice, this is safe, because
there won't be a large number of max7315 devices in the systems, and
both the format and the length are defined by the firmware interface.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170719125310.2487451-9-arnd@arndb.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Arnd Bergmann 2017-07-19 14:53:06 +02:00 committed by Ingo Molnar
parent d689c64d18
commit 0bc73048d7
1 changed files with 4 additions and 2 deletions
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6
arch/x86/platform/intel-mid/device_libs/platform_max7315.c
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@ -38,8 +38,10 @@ static void __init *max7315_platform_data(void *info)
*/
strcpy(i2c_info->type, "max7315");
if (nr++) {
sprintf(base_pin_name, "max7315_%d_base", nr);
sprintf(intr_pin_name, "max7315_%d_int", nr);
snprintf(base_pin_name, sizeof(base_pin_name),
"max7315_%d_base", nr);
snprintf(intr_pin_name, sizeof(intr_pin_name),
"max7315_%d_int", nr);
} else {
strcpy(base_pin_name, "max7315_base");
strcpy(intr_pin_name, "max7315_int");