Hi, Can Guo
>Since WB feature has been added, WB related sysfs entries can be accessed
>even when an UFS device does not support WB feature. In that case, the
>descriptors which are not supported by the UFS device may be wrongly
>reported when they are accessed from their corrsponding sysfs entries.
>Fix it by adding a sanity check of parameter offset against the actual
>decriptor length.
>
>Signed-off-by: Can Guo <c...@codeaurora.org>
>---
> drivers/scsi/ufs/ufshcd.c | 24 +++++++++++++++---------
> 1 file changed, 15 insertions(+), 9 deletions(-)
>
>diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>index a2ebcc8..aeec10d 100644
>--- a/drivers/scsi/ufs/ufshcd.c
>+++ b/drivers/scsi/ufs/ufshcd.c
>@@ -3184,13 +3184,19 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
> /* Get the length of descriptor */
> ufshcd_map_desc_id_to_length(hba, desc_id, &buff_len);
> if (!buff_len) {
>- dev_err(hba->dev, "%s: Failed to get desc length", __func__);
>+ dev_err(hba->dev, "%s: Failed to get desc length\n", __func__);
>+ return -EINVAL;
>+ }
>+
>+ if (param_offset >= buff_len) {
>+ dev_err(hba->dev, "%s: Invalid offset 0x%x in descriptor IDN
>0x%x, length 0x%x\n",
>+ __func__, param_offset, desc_id, buff_len);
In my understanding, this code seems to check incorrect access to not
supportted features (e.g. WB) via buff_len value from
ufshcd_map_desc_id_to_length().
However, since buff_len is initialized as QUERY_DESC_MAX_SIZE and is
updated later by ufshcd_update_desc_length(), So it is impossible to find
incorrect access by checking buff_len at first time.
Thanks,
Daejun
