[PATCH 4/4] misc: fastrpc: reject non-secure node for secure domain

Jeya R
2021-09-24T12:19:38Z

Reject session if domain is secure and device non-secure. Also check if
opened device node is proper.

Signed-off-by: Jeya R <jeyr@codeaurora.org>
---
drivers/misc/fastrpc.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 631713d..adf2700 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -235,6 +235,7 @@ struct fastrpc_user {
spinlock_t lock;
/* lock for allocations */
struct mutex mutex;
+ int dev_minor;
};

static void fastrpc_free_map(struct kref *ref)
@@ -1013,6 +1014,17 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl, u32 kernel,
return err;
}

+static int is_session_rejected(struct fastrpc_user *fl)
+{
+ /* Check if the device node is non-secure and channel is secure*/
+ if ((fl->dev_minor == fl->cctx->miscdev.minor) && fl->cctx->secure) {
+ dev_err(&fl->cctx->rpdev->dev, "Cannot use non-secure device"
+ "node on secure channel\n");
+ return -EACCES;
+ }
+ return 0;
+}
+
static int fastrpc_init_create_process(struct fastrpc_user *fl,
char __user *argp)
{
@@ -1033,6 +1045,10 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
} inbuf;
u32 sc;

+ err = is_session_rejected(fl);
+ if (err)
+ return err;
+
args = kcalloc(FASTRPC_CREATE_PROCESS_NARGS, sizeof(*args), GFP_KERNEL);
if (!args)
return -ENOMEM;
@@ -1221,6 +1237,7 @@ static int fastrpc_device_open(struct inode *inode, struct file *filp)
struct fastrpc_user *fl = NULL;
struct miscdevice *currdev = NULL;
unsigned long flags;
+ int dev_minor = MINOR(inode->i_rdev);

if (!filp)
return -EFAULT;
@@ -1234,6 +1251,12 @@ static int fastrpc_device_open(struct inode *inode, struct file *filp)
else
cctx = miscdev_to_cctx(filp->private_data);

+ if (!((dev_minor == cctx->miscdev.minor) ||
+ (dev_minor == cctx->securedev.minor))) {
+ dev_err(&cctx->rpdev->dev, "Device node is not proper\n");
+ return -EFAULT;
+ }
+
fl = kzalloc(sizeof(*fl), GFP_KERNEL);
if (!fl)
return -ENOMEM;
@@ -1250,6 +1273,7 @@ static int fastrpc_device_open(struct inode *inode, struct file *filp)
INIT_LIST_HEAD(&fl->user);
fl->tgid = current->tgid;
fl->cctx = cctx;
+ fl->dev_minor = dev_minor;

fl->sctx = fastrpc_session_alloc(cctx);
if (!fl->sctx) {
--
2.7.4