staging: gasket: always allow root open for write

Always allow root to open device for writing.

Drop special-casing of ioctl permissions for root vs. owner.

Convert to bool types as appropriate.

Reported-by: Dmitry Torokhov <dtor@chromium.org>
Signed-off-by: Zhongze Hu <frankhu@chromium.org>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/gasket/apex_driver.c b/drivers/staging/gasket/apex_driver.c
index a01b1f2b827ea2e7fc1b74fcb84cf638e07a4486..4c00f3609f081599f8a1c971de89ce871a218f2a 100644 (file)
--- a/drivers/staging/gasket/apex_driver.c
+++ b/drivers/staging/gasket/apex_driver.c
@@ -140,7 +140,7 @@ static int apex_reset(struct gasket_dev *gasket_dev, uint type);
 
 static int apex_get_status(struct gasket_dev *gasket_dev);
 
-static uint apex_ioctl_check_permissions(struct file *file, uint cmd);
+static bool apex_ioctl_check_permissions(struct file *file, uint cmd);
 
 static long apex_ioctl(struct file *file, uint cmd, ulong arg);
 
@@ -625,18 +625,11 @@ static bool is_gcb_in_reset(struct gasket_dev *gasket_dev)
  * @file: File pointer from ioctl.
  * @cmd: ioctl command.
  *
- * Returns 1 if the current user may execute this ioctl, and 0 otherwise.
+ * Returns true if the current user may execute this ioctl, and false otherwise.
  */
-static uint apex_ioctl_check_permissions(struct file *filp, uint cmd)
+static bool apex_ioctl_check_permissions(struct file *filp, uint cmd)
 {
-       struct gasket_dev *gasket_dev = filp->private_data;
-       int root = capable(CAP_SYS_ADMIN);
-       int is_owner = gasket_dev->dev_info.ownership.is_owned &&
-                      current->tgid == gasket_dev->dev_info.ownership.owner;
-
-       if (root || is_owner)
-               return 1;
-       return 0;
+       return !!(filp->f_mode & FMODE_WRITE);
 }
 
 /*

diff --git a/drivers/staging/gasket/gasket_core.c b/drivers/staging/gasket/gasket_core.c
index ba48a379b0ada0c4641ca8f2a45d9610fb540a5e..254fb392c05c18ab9f822c98eb873cce6cca596e 100644 (file)
--- a/drivers/staging/gasket/gasket_core.c
+++ b/drivers/staging/gasket/gasket_core.c
@@ -1072,6 +1072,7 @@ static int gasket_open(struct inode *inode, struct file *filp)
        char task_name[TASK_COMM_LEN];
        struct gasket_cdev_info *dev_info =
            container_of(inode->i_cdev, struct gasket_cdev_info, cdev);
+       int is_root = capable(CAP_SYS_ADMIN);
 
        gasket_dev = dev_info->gasket_dev_ptr;
        driver_desc = gasket_dev->internal_desc->driver_desc;
@@ -1085,7 +1086,7 @@ static int gasket_open(struct inode *inode, struct file *filp)
                "Attempting to open with tgid %u (%s) (f_mode: 0%03o, "
                "fmode_write: %d is_root: %u)",
                current->tgid, task_name, filp->f_mode,
-               (filp->f_mode & FMODE_WRITE), capable(CAP_SYS_ADMIN));
+               (filp->f_mode & FMODE_WRITE), is_root);
 
        /* Always allow non-writing accesses. */
        if (!(filp->f_mode & FMODE_WRITE)) {
@@ -1099,8 +1100,9 @@ static int gasket_open(struct inode *inode, struct file *filp)
                gasket_dev, "Current owner open count (owning tgid %u): %d.",
                ownership->owner, ownership->write_open_count);
 
-       /* Opening a node owned by another TGID is an error (even root.) */
-       if (ownership->is_owned && ownership->owner != current->tgid) {
+       /* Opening a node owned by another TGID is an error (unless root) */
+       if (ownership->is_owned && ownership->owner != current->tgid &&
+           !is_root) {
                gasket_log_error(
                        gasket_dev,
                        "Process %u is opening a node held by %u.",

diff --git a/drivers/staging/gasket/gasket_ioctl.c b/drivers/staging/gasket/gasket_ioctl.c
index d0142ed048a65bc3a38d6717baa792739eafc9e5..8fd44979fe7133f0b2c2ed8436fc63db3ceae92d 100644 (file)
--- a/drivers/staging/gasket/gasket_ioctl.c
+++ b/drivers/staging/gasket/gasket_ioctl.c
@@ -22,7 +22,7 @@
 #define trace_gasket_ioctl_config_coherent_allocator(x, ...)
 #endif
 
-static uint gasket_ioctl_check_permissions(struct file *filp, uint cmd);
+static bool gasket_ioctl_check_permissions(struct file *filp, uint cmd);
 static int gasket_set_event_fd(struct gasket_dev *dev, ulong arg);
 static int gasket_read_page_table_size(
        struct gasket_dev *gasket_dev, ulong arg);
@@ -167,12 +167,13 @@ long gasket_is_supported_ioctl(uint cmd)
  * @filp: File structure pointer describing this node usage session.
  * @cmd: ioctl number to handle.
  *
- * Standard permissions checker.
+ * Check permissions for Gasket ioctls.
+ * Returns true if the file opener may execute this ioctl, or false otherwise.
  */
-static uint gasket_ioctl_check_permissions(struct file *filp, uint cmd)
+static bool gasket_ioctl_check_permissions(struct file *filp, uint cmd)
 {
-       uint alive, root, device_owner;
-       fmode_t read, write;
+       bool alive;
+       bool read, write;
        struct gasket_dev *gasket_dev = (struct gasket_dev *)filp->private_data;
 
        alive = (gasket_dev->status == GASKET_STATUS_ALIVE);
@@ -183,36 +184,33 @@ static uint gasket_ioctl_check_permissions(struct file *filp, uint cmd)
                        alive, gasket_dev->status);
        }
 
-       root = capable(CAP_SYS_ADMIN);
-       read = filp->f_mode & FMODE_READ;
-       write = filp->f_mode & FMODE_WRITE;
-       device_owner = (gasket_dev->dev_info.ownership.is_owned &&
-                       current->tgid == gasket_dev->dev_info.ownership.owner);
+       read = !!(filp->f_mode & FMODE_READ);
+       write = !!(filp->f_mode & FMODE_WRITE);
 
        switch (cmd) {
        case GASKET_IOCTL_RESET:
        case GASKET_IOCTL_CLEAR_INTERRUPT_COUNTS:
-               return root || (write && device_owner);
+               return write;
 
        case GASKET_IOCTL_PAGE_TABLE_SIZE:
        case GASKET_IOCTL_SIMPLE_PAGE_TABLE_SIZE:
        case GASKET_IOCTL_NUMBER_PAGE_TABLES:
-               return root || read;
+               return read;
 
        case GASKET_IOCTL_PARTITION_PAGE_TABLE:
        case GASKET_IOCTL_CONFIG_COHERENT_ALLOCATOR:
-               return alive && (root || (write && device_owner));
+               return alive && write;
 
        case GASKET_IOCTL_MAP_BUFFER:
        case GASKET_IOCTL_UNMAP_BUFFER:
-               return alive && (root || (write && device_owner));
+               return alive && write;
 
        case GASKET_IOCTL_CLEAR_EVENTFD:
        case GASKET_IOCTL_SET_EVENTFD:
-               return alive && (root || (write && device_owner));
+               return alive && write;
        }
 
-       return 0; /* unknown permissions */
+       return false; /* unknown permissions */
 }
 
 /*