> -----Original Message----- > From: sathyanarayanan kuppuswamy > [mailto:sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx] > Sent: Wednesday, November 8, 2017 12:23 PM > To: Arnd Bergmann <arnd@xxxxxxxx>; Pali Rohár <pali.rohar@xxxxxxxxx>; > Limonciello, Mario <Mario_Limonciello@xxxxxxxx>; Darren Hart > <dvhart@xxxxxxxxxxxxx>; Andy Shevchenko <andy@xxxxxxxxxxxxx> > Cc: Edward O'Callaghan <quasisec@xxxxxxxxxx>; Hans de Goede > <hdegoede@xxxxxxxxxx>; platform-driver-x86@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] dell-smbios: fix string overflow > > Hi, > > I recommend using "platform/x86: dell-smbios:" in commit header. > > On 11/08/2017 04:08 AM, Arnd Bergmann wrote: > > The new sysfs code overwrites two fixed-length character arrays > > that are each one byte shorter than they need to be, to hold > > the trailing \0: > > > > drivers/platform/x86/dell-smbios.c: In function 'build_tokens_sysfs': > > drivers/platform/x86/dell-smbios.c:494:42: error: 'sprintf' writing a terminating > nul past the end of the destination [-Werror=format-overflow=] > > sprintf(buffer_location, "%04x_location", > > drivers/platform/x86/dell-smbios.c:494:3: note: 'sprintf' output 14 bytes into a > destination of size 13 > > drivers/platform/x86/dell-smbios.c:506:36: error: 'sprintf' writing a terminating > nul past the end of the destination [-Werror=format-overflow=] > > sprintf(buffer_value, "%04x_value", > > drivers/platform/x86/dell-smbios.c:506:3: note: 'sprintf' output 11 bytes into a > destination of size 10 > Don't need to include the error log in commit message. Just explaining > the issue is good enough. > > > > This changes it to just use kasprintf(), which always gets it right. > > > > Fixes: 33b9ca1e53b4 ("platform/x86: dell-smbios: Add a sysfs interface for > SMBIOS tokens") > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > > --- > > drivers/platform/x86/dell-smbios.c | 12 ++++-------- > > 1 file changed, 4 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/platform/x86/dell-smbios.c b/drivers/platform/x86/dell- > smbios.c > > index d99edd803c19..6a60db515bda 100644 > > --- a/drivers/platform/x86/dell-smbios.c > > +++ b/drivers/platform/x86/dell-smbios.c > > @@ -463,8 +463,6 @@ static struct platform_driver platform_driver = { > > > > static int build_tokens_sysfs(struct platform_device *dev) > > { > > - char buffer_location[13]; > > - char buffer_value[10]; > > char *location_name; > > char *value_name; > > size_t size; > > @@ -491,9 +489,8 @@ static int build_tokens_sysfs(struct platform_device > *dev) > > if (da_tokens[i].tokenID == 0) > > continue; > > /* add location */ > > - sprintf(buffer_location, "%04x_location", > > - da_tokens[i].tokenID); > > - location_name = kstrdup(buffer_location, GFP_KERNEL); > > + location_name = kasprintf(GFP_KERNEL, "%04x_location", > > + da_tokens[i].tokenID); > > if (location_name == NULL) > > goto out_unwind_strings; > > sysfs_attr_init(&token_location_attrs[i].attr); > > @@ -503,9 +500,8 @@ static int build_tokens_sysfs(struct platform_device > *dev) > > token_attrs[j++] = &token_location_attrs[i].attr; > > > > /* add value */ > > - sprintf(buffer_value, "%04x_value", > > - da_tokens[i].tokenID); > > - value_name = kstrdup(buffer_value, GFP_KERNEL); > > + value_name = kasprintf(GFP_KERNEL, "%04x_value", > > + da_tokens[i].tokenID); > > if (value_name == NULL) > > goto loop_fail_create_value; > > sysfs_attr_init(&token_value_attrs[i].attr); > > -- Arnd, Assuming Darren will do the fixup for title and message as recommended by Sathyanarayanan before committing: Acked-by: Mario Limonciello <mario.limonciello@xxxxxxxx> Thanks, for the fix. For my own information and improvement, would you share how you caught that? Just added "-Werror=format-overflow=" to CFLAGS? I wasn't seeing the compile errors with default flags in my own testing, so I'd like to make sure I'm doing better testing in the future.
