diff options
| author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2019-02-21 14:19:17 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-23 08:44:34 +0100 |
| commit | aa9c7ee2922a557ff430651f2125c2eb28821db6 (patch) | |
| tree | c173ba17dd109fc7e9290f552bac165f8fb0bc26 | |
| parent | 5f4c9964d10710659d6cd6b58134b3aba600dffc (diff) | |
stm class: Prevent division by zero
commit bf7cbaae0831252b416f375ca9b1027ecd4642dd upstream.
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+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/hwtracing/stm/core.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index 8bd1b4dab94e..92ab51aa8a74 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -477,7 +477,7 @@ 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; - int ret = -EINVAL; + int ret = -EINVAL, wlimit = 1; u32 size; if (stmf->output.nr_chans) @@ -505,8 +505,10 @@ 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; ret = stm_file_assign(stmf, id->id, id->width); |