Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1691654 > unrolled thread

[PATCH 8/8] x86: intel-mid: fix a format string overflow warning

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH 8/8] x86: intel-mid: fix a format string overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-19 15:00 +0200
    [tip:x86/urgent] x86/platform/intel-mid: Fix a format string  overflow warning tip-bot for Arnd Bergmann <tipbot@zytor.com> - 2017-07-20 12:40 +0200

#1691654 — [PATCH 8/8] x86: 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>
---
Originally submitted on July 14, this is the same patch with slightly
improved changelog.
---
 arch/x86/platform/intel-mid/device_libs/platform_max7315.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/platform/intel-mid/device_libs/platform_max7315.c b/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
index 6e075afa7877..58337b2bc682 100644
--- a/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
+++ b/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
@@ -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");
-- 
2.9.0

[toc] | [next] | [standalone]

#1692778 — [tip:x86/urgent] x86/platform/intel-mid: Fix a format string overflow warning

Commit-ID:  0bc73048d7baecf94117d1a948853a627e6ba5c8
Gitweb:     http://git.kernel.org/tip/0bc73048d7baecf94117d1a948853a627e6ba5c8
Author:     Arnd Bergmann <arnd@arndb.de>
AuthorDate: Wed, 19 Jul 2017 14:53:06 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 20 Jul 2017 10:46:25 +0200

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>
---
 arch/x86/platform/intel-mid/device_libs/platform_max7315.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/platform/intel-mid/device_libs/platform_max7315.c b/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
index 6e075af..58337b2 100644
--- a/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
+++ b/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
@@ -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");

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web