Messages in this thread Patch in this message | | | Date | Mon, 3 Feb 2020 13:22:16 -0800 | Subject | [PATCH] psi: Fix OOB write when writing 0 bytes to psi files | From | Suren Baghdasaryan <> |
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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> --- kernel/sched/psi.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index db7b50bba3f1..38ccd49b9bf6 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; -- 2.25.0.341.g760bfbb309-goog
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