From: Todd Poynor <toddpoy...@google.com>
Always allow root to open device for writing.
Drop special-casing of ioctl permissions for root vs. owner.
Reported-by: Dmitry Torokhov <d...@chromium.org>
Signed-off-by: Zhongze Hu <fran...@chromium.org>
Signed-off-by: Todd Poynor <toddpoy...@google.com>
---
drivers/staging/gasket/apex_driver.c | 9 +--------
drivers/staging/gasket/gasket_core.c | 8 +++++---
drivers/staging/gasket/gasket_ioctl.c | 19 ++++++++-----------
3 files changed, 14 insertions(+), 22 deletions(-)
diff --git a/drivers/staging/gasket/apex_driver.c
b/drivers/staging/gasket/apex_driver.c
index 3a83c3d4d5561..612b3ab803196 100644
--- a/drivers/staging/gasket/apex_driver.c
+++ b/drivers/staging/gasket/apex_driver.c
@@ -629,14 +629,7 @@ static bool is_gcb_in_reset(struct gasket_dev *gasket_dev)
*/
static uint 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 0d5ba7359af73..947b4fcc76970 100644
--- a/drivers/staging/gasket/gasket_core.c
+++ b/drivers/staging/gasket/gasket_core.c
@@ -1085,6 +1085,7 @@ 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;
@@ -1098,7 +1099,7 @@ 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)) {
@@ -1112,8 +1113,9 @@ 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 0c2f85cf54480..d0fa05b8bf1d3 100644
--- a/drivers/staging/gasket/gasket_ioctl.c
+++ b/drivers/staging/gasket/gasket_ioctl.c
@@ -171,7 +171,7 @@ long gasket_is_supported_ioctl(uint cmd)
*/
static uint gasket_ioctl_check_permissions(struct file *filp, uint cmd)
{
- uint alive, root, device_owner;
+ uint alive;
fmode_t read, write;
struct gasket_dev *gasket_dev = (struct gasket_dev *)filp->private_data;
@@ -183,33 +183,30 @@ 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 */
--
2.18.0.203.gfac676dfb9-goog
