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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2019-02-21 14:19:17 +0200
committerAlexander Shishkin <alexander.shishkin@linux.intel.com>2019-02-21 17:44:18 +0200
commitbf7cbaae0831252b416f375ca9b1027ecd4642dd (patch)
tree4cb6da8afa3f5081b5e3ab7c2c8e2197c9aa7325 /drivers/hwtracing
parenta1d75dad3a2c689e70a1c4e0214cca9de741d0aa (diff)
downloadlinux-stericsson-bf7cbaae0831252b416f375ca9b1027ecd4642dd.tar.gz
stm class: Prevent division by zero
Using STP_POLICY_ID_SET ioctl command with dummy_stm device, or any STM device that supplies zero mmio channel size, will trigger a division by zero bug in the kernel. Prevent this by disallowing channel widths other than 1 for such devices. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Fixes: 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices") CC: stable@vger.kernel.org # v4.4+
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/stm/core.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index c80b064224f6..c7ba8acfd4d5 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -735,7 +735,7 @@ static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg)
struct stm_device *stm = stmf->stm;
struct stp_policy_id *id;
char *ids[] = { NULL, NULL };
- int ret = -EINVAL;
+ int ret = -EINVAL, wlimit = 1;
u32 size;
if (stmf->output.nr_chans)
@@ -763,8 +763,10 @@ static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg)
if (id->__reserved_0 || id->__reserved_1)
goto err_free;
- if (id->width < 1 ||
- id->width > PAGE_SIZE / stm->data->sw_mmiosz)
+ if (stm->data->sw_mmiosz)
+ wlimit = PAGE_SIZE / stm->data->sw_mmiosz;
+
+ if (id->width < 1 || id->width > wlimit)
goto err_free;
ids[0] = id->id;