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Message-Id: <20180717020926.176408-17-toddpoynor@gmail.com>
Date: Mon, 16 Jul 2018 19:09:10 -0700
From: Todd Poynor <toddpoynor@...il.com>
To: Rob Springer <rspringer@...gle.com>,
John Joseph <jnjoseph@...gle.com>,
Ben Chan <benchan@...omium.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Zhongze Hu <frankhu@...omium.org>, Simon Que <sque@...omium.org>,
Dmitry Torokhov <dtor@...omium.org>,
Guenter Roeck <groeck@...omium.org>,
devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
Todd Poynor <toddpoynor@...gle.com>
Subject: [PATCH 16/32] staging: gasket: always allow root open for write
From: Todd Poynor <toddpoynor@...gle.com>
Always allow root to open device for writing.
Drop special-casing of ioctl permissions for root vs. owner.
Reported-by: Dmitry Torokhov <dtor@...omium.org>
Signed-off-by: Zhongze Hu <frankhu@...omium.org>
Signed-off-by: Todd Poynor <toddpoynor@...gle.com>
Reviewed-by: Dmitry Torokhov <dtor@...omium.org>
---
drivers/staging/gasket/apex_driver.c | 9 +++------
drivers/staging/gasket/gasket_core.c | 8 +++++---
drivers/staging/gasket/gasket_ioctl.c | 15 ++++++---------
3 files changed, 14 insertions(+), 18 deletions(-)
diff --git a/drivers/staging/gasket/apex_driver.c b/drivers/staging/gasket/apex_driver.c
index 3a83c3d4d5561..6fd09c45a3df6 100644
--- a/drivers/staging/gasket/apex_driver.c
+++ b/drivers/staging/gasket/apex_driver.c
@@ -630,13 +630,10 @@ 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;
+ fmode_t write;
- if (root || is_owner)
- return 1;
- return 0;
+ write = filp->f_mode & FMODE_WRITE;
+ return write;
}
/*
diff --git a/drivers/staging/gasket/gasket_core.c b/drivers/staging/gasket/gasket_core.c
index ae20b7ff9569b..9d1bb3caf6de2 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..17431d14e6ef1 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);
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
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