| From f54303dfb1116786ac15c813e2d4ba8803748207 Mon Sep 17 00:00:00 2001 |
| From: Suren Baghdasaryan <surenb@google.com> |
| Date: Mon, 3 Feb 2020 13:22:16 -0800 |
| Subject: [PATCH] sched/psi: Fix OOB write when writing 0 bytes to PSI files |
| |
| commit 6fcca0fa48118e6d63733eb4644c6cd880c15b8f upstream. |
| |
| Issuing write() with count parameter set to 0 on any file under |
| /proc/pressure/ will cause an OOB write because of the access to |
| buf[buf_size-1] when NUL-termination is performed. Fix this by checking |
| for buf_size to be non-zero. |
| |
| Signed-off-by: Suren Baghdasaryan <surenb@google.com> |
| Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Acked-by: Johannes Weiner <hannes@cmpxchg.org> |
| Link: https://lkml.kernel.org/r/20200203212216.7076-1-surenb@google.com |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c |
| index ce8f6748678a..9154e745f097 100644 |
| --- a/kernel/sched/psi.c |
| +++ b/kernel/sched/psi.c |
| @@ -1199,6 +1199,9 @@ static ssize_t psi_write(struct file *file, const char __user *user_buf, |
| if (static_branch_likely(&psi_disabled)) |
| return -EOPNOTSUPP; |
| |
| + if (!nbytes) |
| + return -EINVAL; |
| + |
| buf_size = min(nbytes, sizeof(buf)); |
| if (copy_from_user(buf, user_buf, buf_size)) |
| return -EFAULT; |
| -- |
| 2.7.4 |
| |
