| Message ID | 20230925-strncpy-drivers-hwmon-acpi_power_meter-c-v4-1-3bac7534f10f@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v4] hwmon: (acpi_power_meter) replace open-coded kmemdup_nul | expand |
On Mon, Sep 25, 2023 at 03:43:23AM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > Let's refactor this kcalloc() + strncpy() into a kmemdup_nul() which has > more obvious behavior and is less error prone. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> > --- > Changes in v4: > - drop +1 from length arg (thanks Kees) > - reword subject line (thanks Kees) > - rebase onto 6465e260f4879080 > - Link to v3: https://lore.kernel.org/r/20230921-strncpy-drivers-hwmon-acpi_power_meter-c-v3-1-307552c6ec3f@google.com > > Changes in v3: > - refactor to use kmemdup_nul() (thanks Thomas and Kees) > - change commit msg to reflect ^ > - rebase onto 2cf0f71562387282 > - Link to v2: https://lore.kernel.org/r/20230919-strncpy-drivers-hwmon-acpi_power_meter-c-v2-1-8348432d6442@google.com > > Changes in v2: > - use memcpy over strscpy (thanks Kees) > - Link to v1: https://lore.kernel.org/r/20230914-strncpy-drivers-hwmon-acpi_power_meter-c-v1-1-905297479fe8@google.com > --- > drivers/hwmon/acpi_power_meter.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c > index fa28d447f0df..c13b5c8a0433 100644 > --- a/drivers/hwmon/acpi_power_meter.c > +++ b/drivers/hwmon/acpi_power_meter.c > @@ -796,14 +796,13 @@ static int read_capabilities(struct acpi_power_meter_resource *resource) > goto error; > } > > - *str = kcalloc(element->string.length + 1, sizeof(u8), > - GFP_KERNEL); > + *str = kmemdup_nul(element->string.pointer, element->string.length, > + GFP_KERNEL); This whitespace looks weird -- I'd expect this to line up with "element", like this: > + *str = kmemdup_nul(element->string.pointer, element->string.length, > + GFP_KERNEL); Otherwise, yes, looks correct.
diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c index fa28d447f0df..c13b5c8a0433 100644 --- a/drivers/hwmon/acpi_power_meter.c +++ b/drivers/hwmon/acpi_power_meter.c @@ -796,14 +796,13 @@ static int read_capabilities(struct acpi_power_meter_resource *resource) goto error; } - *str = kcalloc(element->string.length + 1, sizeof(u8), - GFP_KERNEL); + *str = kmemdup_nul(element->string.pointer, element->string.length, + GFP_KERNEL); if (!*str) { res = -ENOMEM; goto error; } - strncpy(*str, element->string.pointer, element->string.length); str++; }
`strncpy` is deprecated for use on NUL-terminated destination strings [1]. Let's refactor this kcalloc() + strncpy() into a kmemdup_nul() which has more obvious behavior and is less error prone. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- Changes in v4: - drop +1 from length arg (thanks Kees) - reword subject line (thanks Kees) - rebase onto 6465e260f4879080 - Link to v3: https://lore.kernel.org/r/20230921-strncpy-drivers-hwmon-acpi_power_meter-c-v3-1-307552c6ec3f@google.com Changes in v3: - refactor to use kmemdup_nul() (thanks Thomas and Kees) - change commit msg to reflect ^ - rebase onto 2cf0f71562387282 - Link to v2: https://lore.kernel.org/r/20230919-strncpy-drivers-hwmon-acpi_power_meter-c-v2-1-8348432d6442@google.com Changes in v2: - use memcpy over strscpy (thanks Kees) - Link to v1: https://lore.kernel.org/r/20230914-strncpy-drivers-hwmon-acpi_power_meter-c-v1-1-905297479fe8@google.com --- drivers/hwmon/acpi_power_meter.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- base-commit: 6465e260f48790807eef06b583b38ca9789b6072 change-id: 20230914-strncpy-drivers-hwmon-acpi_power_meter-c-c9f2d8053bef Best regards, -- Justin Stitt <justinstitt@google.com>