diff options
Diffstat (limited to 'block/ioprio.c')
| -rw-r--r-- | block/ioprio.c | 44 |
1 files changed, 11 insertions, 33 deletions
diff --git a/block/ioprio.c b/block/ioprio.c index 0e4ff245f2bf..2fe068fcaad5 100644 --- a/block/ioprio.c +++ b/block/ioprio.c @@ -22,46 +22,14 @@ */ #include <linux/gfp.h> #include <linux/kernel.h> -#include <linux/export.h> #include <linux/ioprio.h> #include <linux/cred.h> #include <linux/blkdev.h> #include <linux/capability.h> -#include <linux/sched/user.h> -#include <linux/sched/task.h> #include <linux/syscalls.h> #include <linux/security.h> #include <linux/pid_namespace.h> -int set_task_ioprio(struct task_struct *task, int ioprio) -{ - int err; - struct io_context *ioc; - const struct cred *cred = current_cred(), *tcred; - - rcu_read_lock(); - tcred = __task_cred(task); - if (!uid_eq(tcred->uid, cred->euid) && - !uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) { - rcu_read_unlock(); - return -EPERM; - } - rcu_read_unlock(); - - err = security_task_setioprio(task, ioprio); - if (err) - return err; - - ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE); - if (ioc) { - ioc->ioprio = ioprio; - put_io_context(ioc); - } - - return err; -} -EXPORT_SYMBOL_GPL(set_task_ioprio); - int ioprio_check_cap(int ioprio) { int class = IOPRIO_PRIO_CLASS(ioprio); @@ -69,7 +37,14 @@ int ioprio_check_cap(int ioprio) switch (class) { case IOPRIO_CLASS_RT: - if (!capable(CAP_SYS_NICE) && !capable(CAP_SYS_ADMIN)) + /* + * Originally this only checked for CAP_SYS_ADMIN, + * which was implicitly allowed for pid 0 by security + * modules such as SELinux. Make sure we check + * CAP_SYS_ADMIN first to avoid a denial/avc for + * possibly missing CAP_SYS_NICE permission. + */ + if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_NICE)) return -EPERM; fallthrough; /* rt has prio field too */ @@ -213,6 +188,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who) pgrp = task_pgrp(current); else pgrp = find_vpid(who); + read_lock(&tasklist_lock); do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { tmpio = get_task_ioprio(p); if (tmpio < 0) @@ -222,6 +198,8 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who) else ret = ioprio_best(ret, tmpio); } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); + read_unlock(&tasklist_lock); + break; case IOPRIO_WHO_USER: uid = make_kuid(current_user_ns(), who); |