From e7585bf384e2973b10b1ebd86d1aafe6169fa7b4 Mon Sep 17 00:00:00 2001 From: Todd Poynor Date: Sun, 29 Jul 2018 12:36:37 -0700 Subject: [PATCH] staging: gasket: core: allow root access based on user namespace Use user namespace to determine whether gasket device file opener is root, allowing root access to containers, if necessary. Reported-by: Dmitry Torokhov Signed-off-by: Todd Poynor Signed-off-by: Greg Kroah-Hartman --- gasket_core.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/gasket_core.c b/gasket_core.c index b90726f..4632607 100644 --- a/gasket_core.c +++ b/gasket_core.c @@ -13,13 +13,16 @@ #include "gasket_page_table.h" #include "gasket_sysfs.h" +#include #include #include #include #include #include #include +#include #include +#include #ifdef GASKET_KERNEL_TRACE_SUPPORT #define CREATE_TRACE_POINTS @@ -1074,7 +1077,8 @@ 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); + struct pid_namespace *pid_ns = task_active_pid_ns(current); + int is_root = ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN); gasket_dev = dev_info->gasket_dev_ptr; driver_desc = gasket_dev->internal_desc->driver_desc; @@ -1157,6 +1161,8 @@ static int gasket_release(struct inode *inode, struct file *file) char task_name[TASK_COMM_LEN]; struct gasket_cdev_info *dev_info = container_of(inode->i_cdev, struct gasket_cdev_info, cdev); + struct pid_namespace *pid_ns = task_active_pid_ns(current); + int is_root = ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN); gasket_dev = dev_info->gasket_dev_ptr; driver_desc = gasket_dev->internal_desc->driver_desc; @@ -1168,7 +1174,7 @@ static int gasket_release(struct inode *inode, struct file *file) "Releasing device node. Call origin: tgid %u (%s) " "(f_mode: 0%03o, fmode_write: %d, is_root: %u)\n", current->tgid, task_name, file->f_mode, - (file->f_mode & FMODE_WRITE), capable(CAP_SYS_ADMIN)); + (file->f_mode & FMODE_WRITE), is_root); dev_dbg(gasket_dev->dev, "Current open count (owning tgid %u): %d\n", ownership->owner, ownership->write_open_count);