fs: raw storage needs PR_CAP_RAWIO

Opening a block or MTD node, mount() and umount2() need it, and so does
a BCH character node, which checks in its own open(): a node made by
bchdev_register() is a character driver, so the inode type cannot tell
it apart. The checks sit in file_vopen(), nx_mount() and nx_umount2(),
which every path reaches; kernel threads hold every capability.

Signed-off-by: Royyan Zahir <royzah@gmail.com>

drivers/bch/bchdev_driver.c

@@ -39,6 +39,7 @@
 #include <assert.h>
 #include <nuttx/debug.h>
 
+#include <nuttx/sched.h>
 #include <nuttx/fs/fs.h>
 #include <nuttx/fs/ioctl.h>
 #include <nuttx/drivers/drivers.h>
@@ -122,6 +123,11 @@ static int bch_open(FAR struct file *filep)
   FAR struct bchlib_s *bch;
   int ret = OK;
 
+  if (!nxsched_capable(PR_CAP_RAWIO))
+    {
+      return -EPERM;
+    }
+
   DEBUGASSERT(inode->i_private);
   bch = inode->i_private;
 

fs/mount/fs_mount.c

@@ -34,6 +34,7 @@
 #include <nuttx/debug.h>
 
 #include <nuttx/fs/fs.h>
+#include <nuttx/sched.h>
 
 #include "driver/driver.h"
 #include "inode/inode.h"
@@ -304,6 +305,11 @@ int nx_mount(FAR const char *source, FAR const char *target,
   FAR void *fshandle = NULL;
   int ret;
 
+  if (!nxsched_capable(PR_CAP_RAWIO))
+    {
+      return -EPERM;
+    }
+
   /* Verify required pointer arguments */
 
   DEBUGASSERT(target && filesystemtype);

fs/mount/fs_umount2.c

@@ -32,6 +32,7 @@
 #include <assert.h>
 
 #include <nuttx/fs/fs.h>
+#include <nuttx/sched.h>
 
 #include "inode/inode.h"
 #include "vfs/vfs.h"
@@ -62,6 +63,11 @@ int nx_umount2(FAR const char *target, unsigned int flags)
   struct inode_search_s desc;
   int ret;
 
+  if (!nxsched_capable(PR_CAP_RAWIO))
+    {
+      return -EPERM;
+    }
+
   /* Verify required pointer arguments */
 
   if (!target)

fs/vfs/fs_open.c

@@ -148,6 +148,13 @@ static int file_vopen(FAR struct file *filep, FAR const char *path,
     }
 #endif
 
+  if ((INODE_IS_BLOCK(inode) || INODE_IS_MTD(inode)) &&
+      !nxsched_capable(PR_CAP_RAWIO))
+    {
+      ret = -EPERM;
+      goto errout_with_inode;
+    }
+
 #if defined(CONFIG_BCH) && \
     !defined(CONFIG_DISABLE_MOUNTPOINT) && \
     !defined(CONFIG_DISABLE_PSEUDOFS_OPERATIONS)