summaryrefslogtreecommitdiffstats
path: root/fs/proc
diff options
context:
space:
mode:
authorPaul Moore <paul@paul-moore.com>2019-04-19 14:55:12 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-25 18:23:25 +0200
commit7928396df91eab24047ab5d8fb105adfe9f50daa (patch)
treef96429f1d68ceb014368df4c99fa28f977e040e9 /fs/proc
parentbbd559ad3ca7b32092dc9747a2050c011789c267 (diff)
downloadlinux-stable-7928396df91eab24047ab5d8fb105adfe9f50daa.tar.gz
linux-stable-7928396df91eab24047ab5d8fb105adfe9f50daa.tar.bz2
linux-stable-7928396df91eab24047ab5d8fb105adfe9f50daa.zip
proc: prevent changes to overridden credentials
commit 35a196bef449b5824033865b963ed9a43fb8c730 upstream. Prevent userspace from changing the the /proc/PID/attr values if the task's credentials are currently overriden. This not only makes sense conceptually, it also prevents some really bizarre error cases caused when trying to commit credentials to a task with overridden credentials. Cc: <stable@vger.kernel.org> Reported-by: "chengjian (D)" <cj.chengjian@huawei.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: James Morris <james.morris@microsoft.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 81d77b15b347..f999e8bd3771 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2542,6 +2542,11 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
rcu_read_unlock();
return -EACCES;
}
+ /* Prevent changes to overridden credentials. */
+ if (current_cred() != current_real_cred()) {
+ rcu_read_unlock();
+ return -EBUSY;
+ }
rcu_read_unlock();
if (count > PAGE_SIZE)