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| author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2018-12-19 17:19:22 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-19 20:21:06 +0100 |
| commit | ec5b5ad6e272d8d6b92d1007f79574919862a2d2 (patch) | |
| tree | 3d2973f90448c4ba3c36b5945642960425dd8d0a /drivers/hwtracing/intel_th/msu.c | |
| parent | 4cdd41585c5196f75e1e496c4f64345b2c700e0b (diff) | |
intel_th: msu: Fix an off-by-one in attribute store
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@linux.intel.com>
Fixes: ba82664c134ef ("intel_th: Add Memory Storage Unit driver")
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hwtracing/intel_th/msu.c')
| -rw-r--r-- | drivers/hwtracing/intel_th/msu.c | 3 |
1 files changed, 2 insertions, 1 deletions
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); |