HID: CVE-2018-9516

HID: debug: check length before copy_to_user()

Reference:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.9.y&id=4a30c12542290f1def08b9ef0d677c024c500589

Change-Id: I2c6c79c1f44b3ef6f9c5e386d3c1c5c3971da7da
Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>

2 files changed, 62 insertions, 0 deletions

diff --git a/patches/cve/4.9.x.scc b/patches/cve/4.9.x.scc
index 96a5b31..c9bec68 100644
--- a/patches/cve/4.9.x.scc
+++ b/patches/cve/4.9.x.scc
@@ -15,3 +15,6 @@ SRC_URI += "file://CVE-2017-18255-perf-core-Fix-the-perf_cpu_time_max_percent-ch
 
 #CVEs fixed in 4.9.111:
 SRC_URI += "file://CVE-2018-13406-video-uvesafb-Fix-integer-overflow-in-allocation.patch"
+
+#CVEs fixed in 4.9.112:
+SRC_URI += "file://CVE-2018-9516-HID-debug-check-length-before-copy_to_user.patch"
diff --git a/patches/cve/CVE-2018-9516-HID-debug-check-length-before-copy_to_user.patch b/patches/cve/CVE-2018-9516-HID-debug-check-length-before-copy_to_user.patch
new file mode 100644
index 0000000..ccdbb0c
--- /dev/null
+++ b/patches/cve/CVE-2018-9516-HID-debug-check-length-before-copy_to_user.patch
@@ -0,0 +1,59 @@
+From 4a30c12542290f1def08b9ef0d677c024c500589 Mon Sep 17 00:00:00 2001
+From: Daniel Rosenberg <drosen@google.com>
+Date: Mon, 2 Jul 2018 16:59:37 -0700
+Subject: [PATCH] HID: debug: check length before copy_to_user()
+
+commit 717adfdaf14704fd3ec7fa2c04520c0723247eac upstream.
+
+If our length is greater than the size of the buffer, we
+overflow the buffer
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Daniel Rosenberg <drosen@google.com>
+Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
+
+CVE: CVE-2018-9516
+Upstream-Status: Backport [https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.9.y&id=4a30c12542290f1def08b9ef0d677c024c500589]
+
+Signed-off-by: Jiri Kosina <jkosina@suse.cz>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>
+---
+ drivers/hid/hid-debug.c | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c
+index acfb522a432a..29423691c105 100644
+--- a/drivers/hid/hid-debug.c
++++ b/drivers/hid/hid-debug.c
+@@ -1152,6 +1152,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer,
+                        goto out;
+                if (list->tail > list->head) {
+                        len = list->tail - list->head;
++                       if (len > count)
++                               len = count;
+ 
+                        if (copy_to_user(buffer + ret, &list->hid_debug_buf[list->head], len)) {
+                                ret = -EFAULT;
+@@ -1161,6 +1163,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer,
+                        list->head += len;
+                } else {
+                        len = HID_DEBUG_BUFSIZE - list->head;
++                       if (len > count)
++                               len = count;
+ 
+                        if (copy_to_user(buffer, &list->hid_debug_buf[list->head], len)) {
+                                ret = -EFAULT;
+@@ -1168,7 +1172,9 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer,
+                        }
+                        list->head = 0;
+                        ret += len;
+-                       goto copy_rest;
++                       count -= len;
++                       if (count > 0)
++                               goto copy_rest;
+                }
+ 
+        }
+
+