From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>,
linux-kernel@vger.kernel.org,
Alexander Shishkin <alexander.shishkin@linux.intel.com>
Subject: [GIT PULL 7/7] stm class: Prevent division by zero
Date: Thu, 21 Feb 2019 15:49:59 +0200 [thread overview]
Message-ID: <20190221134959.15121-8-alexander.shishkin@linux.intel.com> (raw)
In-Reply-To: <20190221134959.15121-1-alexander.shishkin@linux.intel.com>
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>
---
drivers/hwtracing/stm/core.c | 8 +++++---
1 file 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;
--
2.20.1
next prev parent reply other threads:[~2019-02-21 13:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-21 13:49 [GIT PULL 0/7] stm class/intel_th: Updates for v5.1 Alexander Shishkin
2019-02-21 13:49 ` [GIT PULL 1/7] intel_th: Update ABI documentation Alexander Shishkin
2019-02-21 13:49 ` [GIT PULL 2/7] intel_th: Mark expected switch fall-throughs Alexander Shishkin
2019-02-21 13:49 ` [GIT PULL 3/7] intel_th: Only create useful device nodes Alexander Shishkin
2019-02-21 13:49 ` [GIT PULL 4/7] intel_th: pti: Use sysfs_match_string() helper Alexander Shishkin
2019-02-21 13:49 ` [GIT PULL 5/7] intel_th: Don't reference unassigned outputs Alexander Shishkin
2019-02-21 14:41 ` Greg Kroah-Hartman
2019-02-21 13:49 ` [GIT PULL 6/7] stm class: Fix an endless loop in channel allocation Alexander Shishkin
2019-02-21 14:42 ` Greg Kroah-Hartman
2019-02-21 13:49 ` Alexander Shishkin [this message]
2019-02-21 14:42 ` [GIT PULL 7/7] stm class: Prevent division by zero Greg Kroah-Hartman
2019-02-21 14:52 ` Alexander Shishkin
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