| Message ID | 20170714120720.906842-18-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | gcc-7 -Wformat-* warnings | expand |
> -----Original Message----- > From: Arnd Bergmann [mailto:arnd@arndb.de] > Sent: Friday, July 14, 2017 7:07 AM > To: linux-kernel@vger.kernel.org; Darren Hart <dvhart@infradead.org>; Andy > Shevchenko <andy@infradead.org> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Linus Torvalds > <torvalds@linux-foundation.org>; Guenter Roeck <linux@roeck-us.net>; > akpm@linux-foundation.org; netdev@vger.kernel.org; David S . Miller > <davem@davemloft.net>; James E . J . Bottomley <jejb@linux.vnet.ibm.com>; > Martin K . Petersen <martin.petersen@oracle.com>; linux-scsi@vger.kernel.org; > x86@kernel.org; Arnd Bergmann <arnd@arndb.de>; Limonciello, Mario > <Mario_Limonciello@Dell.com>; Arvind Yadav <arvind.yadav.cs@gmail.com>; > platform-driver-x86@vger.kernel.org > Subject: [PATCH 17/22] platform/x86: alienware-wmi: fix format string overflow > warning > > gcc points out a possible format string overflow for a large value of 'zone': > > drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init': > drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing > between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=] > sprintf(buffer, "zone%02X", i); > ^~~~ > drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the > range [0, 2147483646] > sprintf(buffer, "zone%02X", i); > ^~~~~~~~~~ > drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and > 13 bytes into a destination of size 10 > > While the zone should never be that large, it's easy to make the > buffer a few bytes longer so gcc can prove this to be safe. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/platform/x86/alienware-wmi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/platform/x86/alienware-wmi.c > b/drivers/platform/x86/alienware-wmi.c > index 0831b428c217..acc01242da82 100644 > --- a/drivers/platform/x86/alienware-wmi.c > +++ b/drivers/platform/x86/alienware-wmi.c > @@ -421,7 +421,7 @@ static DEVICE_ATTR(lighting_control_state, 0644, > show_control_state, > static int alienware_zone_init(struct platform_device *dev) > { > int i; > - char buffer[10]; > + char buffer[13]; > char *name; > > if (interface == WMAX) { > -- > 2.9.0 LGTM, Thanks. Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
On Fri, Jul 14, 2017 at 3:07 PM, Arnd Bergmann <arnd@arndb.de> wrote: > gcc points out a possible format string overflow for a large value of 'zone': > > drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init': > drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=] > sprintf(buffer, "zone%02X", i); > ^~~~ > drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646] > sprintf(buffer, "zone%02X", i); > ^~~~~~~~~~ > drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10 > > While the zone should never be that large, it's easy to make the > buffer a few bytes longer so gcc can prove this to be safe. Please, be a bit smarter on such fixes. Here we need to convert int i; to u8 i; I will take it after addressing above. P.S. You may do this change across the file. > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/platform/x86/alienware-wmi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/platform/x86/alienware-wmi.c b/drivers/platform/x86/alienware-wmi.c > index 0831b428c217..acc01242da82 100644 > --- a/drivers/platform/x86/alienware-wmi.c > +++ b/drivers/platform/x86/alienware-wmi.c > @@ -421,7 +421,7 @@ static DEVICE_ATTR(lighting_control_state, 0644, show_control_state, > static int alienware_zone_init(struct platform_device *dev) > { > int i; > - char buffer[10]; > + char buffer[13]; > char *name; > > if (interface == WMAX) { > -- > 2.9.0 > -- With Best Regards, Andy Shevchenko
On Fri, Jul 14, 2017 at 9:18 PM, Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > On Fri, Jul 14, 2017 at 3:07 PM, Arnd Bergmann <arnd@arndb.de> wrote: >> gcc points out a possible format string overflow for a large value of 'zone': >> >> drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init': >> drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=] >> sprintf(buffer, "zone%02X", i); >> ^~~~ >> drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646] >> sprintf(buffer, "zone%02X", i); >> ^~~~~~~~~~ >> drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10 >> >> While the zone should never be that large, it's easy to make the >> buffer a few bytes longer so gcc can prove this to be safe. > > Please, be a bit smarter on such fixes. > > Here we need to convert > > int i; > > to > > u8 i; That was my first impulse, but then I decided not to change the idiomatic 'int i' for the index variable to 'u8' as that would be less idiomatic. > I will take it after addressing above. > > P.S. You may do this change across the file. How about changing it to 'u8 zone'? Arnd
On Fri, Jul 14, 2017 at 10:37 PM, Arnd Bergmann <arnd@arndb.de> wrote: > On Fri, Jul 14, 2017 at 9:18 PM, Andy Shevchenko > <andy.shevchenko@gmail.com> wrote: >> On Fri, Jul 14, 2017 at 3:07 PM, Arnd Bergmann <arnd@arndb.de> wrote: >>> gcc points out a possible format string overflow for a large value of 'zone': >> Here we need to convert >> >> int i; >> >> to >> >> u8 i; > > That was my first impulse, but then I decided not to change the > idiomatic 'int i' for the index variable to 'u8' as that would be > less idiomatic. > >> I will take it after addressing above. >> >> P.S. You may do this change across the file. > > How about changing it to 'u8 zone'? I'm ultimately fine with that (just gentle reminder you might fix all 3 occurrences of it in that driver). -- With Best Regards, Andy Shevchenko
diff --git a/drivers/platform/x86/alienware-wmi.c b/drivers/platform/x86/alienware-wmi.c index 0831b428c217..acc01242da82 100644 --- a/drivers/platform/x86/alienware-wmi.c +++ b/drivers/platform/x86/alienware-wmi.c @@ -421,7 +421,7 @@ static DEVICE_ATTR(lighting_control_state, 0644, show_control_state, static int alienware_zone_init(struct platform_device *dev) { int i; - char buffer[10]; + char buffer[13]; char *name; if (interface == WMAX) {
gcc points out a possible format string overflow for a large value of 'zone': drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init': drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=] sprintf(buffer, "zone%02X", i); ^~~~ drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646] sprintf(buffer, "zone%02X", i); ^~~~~~~~~~ drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10 While the zone should never be that large, it's easy to make the buffer a few bytes longer so gcc can prove this to be safe. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/platform/x86/alienware-wmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.9.0