diff options
Diffstat (limited to 'kvm-properly-check-debugfs-dentry-before-using-it.patch')
| -rw-r--r-- | kvm-properly-check-debugfs-dentry-before-using-it.patch | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/kvm-properly-check-debugfs-dentry-before-using-it.patch b/kvm-properly-check-debugfs-dentry-before-using-it.patch new file mode 100644 index 00000000000000..29a8d3c9d70cf2 --- /dev/null +++ b/kvm-properly-check-debugfs-dentry-before-using-it.patch @@ -0,0 +1,38 @@ +From foo@baz Thu Feb 28 16:02:54 CET 2019 +Date: Thu, 28 Feb 2019 16:02:54 +0100 +To: Greg KH <gregkh@linuxfoundation.org> +From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Subject: [PATCH] kvm: properly check debugfs dentry before using it + +debugfs can now report an error code if something went wrong instead of +just NULL. So if the return value is to be used as a "real" dentry, it +needs to be checked if it is an error before dereferencing it. + +This is now happening because of ff9fb72bc077 ("debugfs: return error +values, not NULL"). syzbot has found a way to trigger multiple debugfs +files attempting to be created, which fails, and then the error code +gets passed to dentry_path_raw() which obviously does not like it. + +Reported-by: Eric Biggers <ebiggers@kernel.org> +Reported-and-tested-by: syzbot+7857962b4d45e602b8ad@syzkaller.appspotmail.com +Cc: Paolo Bonzini <pbonzini@redhat.com> +Cc: "Radim Krčmář" <rkrcmar@redhat.com> +Cc: kvm@vger.kernel.org +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> + + +--- + virt/kvm/kvm_main.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/virt/kvm/kvm_main.c ++++ b/virt/kvm/kvm_main.c +@@ -4044,7 +4044,7 @@ static void kvm_uevent_notify_change(uns + } + add_uevent_var(env, "PID=%d", kvm->userspace_pid); + +- if (kvm->debugfs_dentry) { ++ if (!IS_ERR_OR_NULL(kvm->debugfs_dentry)) { + char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL); + + if (p) { |