The 'nr_pages' attribute of the 'msc' subdevices parses a comma-separated
list of window sizes, passed from userspace. However, there is a bug in
the string parsing logic wherein it doesn't exclude the comma character
from the range of characters as it consumes them. This leads to an
out-of-bounds access given a sufficiently long list. For example:
> # echo 8,8,8,8 > /sys/bus/intel_th/devices/0-msc0/nr_pages
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in memchr+0x1e/0x40
> Read of size 1 at addr ffff8803ffcebcd1 by task sh/825
>
> CPU: 3 PID: 825 Comm: npktest.sh Tainted: G W 4.20.0-rc1+
> Call Trace:
> dump_stack+0x7c/0xc0
> print_address_description+0x6c/0x23c
> ? memchr+0x1e/0x40
> kasan_report.cold.5+0x241/0x308
> memchr+0x1e/0x40
> nr_pages_store+0x203/0xd00 [intel_th_msu]
Fix this by accounting for the comma character.
Signed-off-by: Alexander Shishkin <alexander.shishkin(a)linux.intel.com>
Fixes: ba82664c134ef ("intel_th: Add Memory Storage Unit driver")
Cc: stable(a)vger.kernel.org # v4.4+
---
drivers/hwtracing/intel_th/msu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
index d293e55553bd..ba7aaf421f36 100644
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -1423,7 +1423,8 @@ nr_pages_store(struct device *dev, struct device_attribute *attr,
if (!end)
break;
- len -= end - p;
+ /* consume the number and the following comma, hence +1 */
+ len -= end - p + 1;
p = end + 1;
} while (len);
--
2.19.2
If CONFIG_GPOILIB is not set, the stub of gpio_to_desc() should return
the same type of error as regular version: NULL. All the callers
compare the return value of gpio_to_desc() against NULL, so returned
ERR_PTR would be treated as non-error case leading to dereferencing of
error value.
Fixes: 79a9becda894 ("gpiolib: export descriptor-based GPIO interface")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk(a)kernel.org>
---
include/linux/gpio/consumer.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index ed070512b40e..3b01fbcafc94 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -505,7 +505,7 @@ static inline int gpiod_set_consumer_name(struct gpio_desc *desc,
static inline struct gpio_desc *gpio_to_desc(unsigned gpio)
{
- return ERR_PTR(-EINVAL);
+ return NULL;
}
static inline int desc_to_gpio(const struct gpio_desc *desc)
--
2.7.4