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authorBenjamin Gordon <bmgordon@google.com>2019-01-03 15:25:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-01-04 13:13:45 -0800
commit8da0b4f692c6d90b09c91f271517db746a22ff67 (patch)
tree534a079733c187dda524c8f248d1bcbecbf83dc6
parent645ff1e8e704c4f33ab1fcd3c87f95cb9b6d7144 (diff)
downloadlinux-8da0b4f692c6d90b09c91f271517db746a22ff67.tar.bz2
fs/proc/base.c: use ns_capable instead of capable for timerslack_ns
Access to timerslack_ns is controlled by a process having CAP_SYS_NICE in its effective capability set, but the current check looks in the root namespace instead of the process' user namespace. Since a process is allowed to do other activities controlled by CAP_SYS_NICE inside a namespace, it should also be able to adjust timerslack_ns. Link: http://lkml.kernel.org/r/20181030180012.232896-1-bmgordon@google.com Signed-off-by: Benjamin Gordon <bmgordon@google.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: John Stultz <john.stultz@linaro.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Oren Laadan <orenl@cellrox.com> Cc: Ruchi Kandoi <kandoiruchi@google.com> Cc: Rom Lemarchand <romlem@android.com> Cc: Todd Kjos <tkjos@google.com> Cc: Colin Cross <ccross@android.com> Cc: Nick Kralevich <nnk@google.com> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Elliott Hughes <enh@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/base.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index d7fd1ca807d2..58a8dc3fd6c6 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2356,10 +2356,13 @@ static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
return -ESRCH;
if (p != current) {
- if (!capable(CAP_SYS_NICE)) {
+ rcu_read_lock();
+ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+ rcu_read_unlock();
count = -EPERM;
goto out;
}
+ rcu_read_unlock();
err = security_task_setscheduler(p);
if (err) {
@@ -2392,11 +2395,14 @@ static int timerslack_ns_show(struct seq_file *m, void *v)
return -ESRCH;
if (p != current) {
-
- if (!capable(CAP_SYS_NICE)) {
+ rcu_read_lock();
+ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+ rcu_read_unlock();
err = -EPERM;
goto out;
}
+ rcu_read_unlock();
+
err = security_task_getscheduler(p);
if (err)
goto out;