| Message ID | 20210920095556.1175269-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | platform/x86: lg-laptop: Fix possible NULL pointer derefence | expand |
On Mon, Sep 20, 2021 at 11:55:50AM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > When CONFIG_DMI is disabled, dmi_get_system_info() returns a NULL > pointer, which is now caught by a warning: > > In function 'strlen', > inlined from 'acpi_add.part.0' at drivers/platform/x86/lg-laptop.c:658:6: > include/linux/fortify-string.h:25:33: error: argument 1 null where non-null expected [-Werror=nonnull] > 25 | #define __underlying_strlen __builtin_strlen > | ^ > include/linux/fortify-string.h:60:24: note: in expansion of macro '__underlying_strlen' > 60 | return __underlying_strlen(p); > | ^~~~~~~~~~~~~~~~~~~ > drivers/platform/x86/lg-laptop.c: In function 'acpi_add.part.0': > include/linux/fortify-string.h:25:33: note: in a call to built-in function '__builtin_strlen' > 25 | #define __underlying_strlen __builtin_strlen > | ^ > include/linux/fortify-string.h:60:24: note: in expansion of macro '__underlying_strlen' > 60 | return __underlying_strlen(p); > | ^~~~~~~~~~~~~~~~~~~ > > The code in there does not appear essential, so an explicit > NULL check should be sufficient. The string is also printed > to the console, but printk() is able to handle NULL pointer > arguments gracefully. > > Fixes: 8983bfd58d61 ("platform/x86: lg-laptop: Support for battery charge limit on newer models") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/platform/x86/lg-laptop.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/platform/x86/lg-laptop.c b/drivers/platform/x86/lg-laptop.c > index 3e520d5bca07..88b551caeaaf 100644 > --- a/drivers/platform/x86/lg-laptop.c > +++ b/drivers/platform/x86/lg-laptop.c > @@ -655,7 +655,7 @@ static int acpi_add(struct acpi_device *device) > goto out_platform_registered; > } > product = dmi_get_system_info(DMI_PRODUCT_NAME); > - if (strlen(product) > 4) > + if (product && strlen(product) > 4) seems appropriate. --mark > switch (product[4]) { > case '5': > case '6': > -- > 2.29.2 >
Hi Arnd, On 9/20/21 11:55 AM, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > When CONFIG_DMI is disabled, dmi_get_system_info() returns a NULL > pointer, which is now caught by a warning: > > In function 'strlen', > inlined from 'acpi_add.part.0' at drivers/platform/x86/lg-laptop.c:658:6: > include/linux/fortify-string.h:25:33: error: argument 1 null where non-null expected [-Werror=nonnull] > 25 | #define __underlying_strlen __builtin_strlen > | ^ > include/linux/fortify-string.h:60:24: note: in expansion of macro '__underlying_strlen' > 60 | return __underlying_strlen(p); > | ^~~~~~~~~~~~~~~~~~~ > drivers/platform/x86/lg-laptop.c: In function 'acpi_add.part.0': > include/linux/fortify-string.h:25:33: note: in a call to built-in function '__builtin_strlen' > 25 | #define __underlying_strlen __builtin_strlen > | ^ > include/linux/fortify-string.h:60:24: note: in expansion of macro '__underlying_strlen' > 60 | return __underlying_strlen(p); > | ^~~~~~~~~~~~~~~~~~~ > > The code in there does not appear essential, so an explicit > NULL check should be sufficient. The string is also printed > to the console, but printk() is able to handle NULL pointer > arguments gracefully. > > Fixes: 8983bfd58d61 ("platform/x86: lg-laptop: Support for battery charge limit on newer models") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thank you for the patch, but this is already fixed in the pdx86 fixes branch: https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/commit/?h=fixes&id=4c4a3d7cffb42da21ea8891fc7e6808ae05dbcb5 Regards, Hans > --- > drivers/platform/x86/lg-laptop.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/platform/x86/lg-laptop.c b/drivers/platform/x86/lg-laptop.c > index 3e520d5bca07..88b551caeaaf 100644 > --- a/drivers/platform/x86/lg-laptop.c > +++ b/drivers/platform/x86/lg-laptop.c > @@ -655,7 +655,7 @@ static int acpi_add(struct acpi_device *device) > goto out_platform_registered; > } > product = dmi_get_system_info(DMI_PRODUCT_NAME); > - if (strlen(product) > 4) > + if (product && strlen(product) > 4) > switch (product[4]) { > case '5': > case '6': >
diff --git a/drivers/platform/x86/lg-laptop.c b/drivers/platform/x86/lg-laptop.c index 3e520d5bca07..88b551caeaaf 100644 --- a/drivers/platform/x86/lg-laptop.c +++ b/drivers/platform/x86/lg-laptop.c @@ -655,7 +655,7 @@ static int acpi_add(struct acpi_device *device) goto out_platform_registered; } product = dmi_get_system_info(DMI_PRODUCT_NAME); - if (strlen(product) > 4) + if (product && strlen(product) > 4) switch (product[4]) { case '5': case '6':