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authorDaniel Rosenberg <drosen@google.com>2018-07-02 16:59:37 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-11 16:31:32 +0200
commit787b882d9178c35eb2e06e974f3c37fc14829e53 (patch)
tree73e296981646e8e65d3c137c87798bee792a8093
parent9be3ce793708c0b2324b632e22a9214586f7757c (diff)
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> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/hid/hid-debug.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c
index 4f4e7a08a07b..4db8e140f709 100644
--- a/drivers/hid/hid-debug.c
+++ b/drivers/hid/hid-debug.c
@@ -1154,6 +1154,8 @@ copy_rest:
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;
@@ -1163,6 +1165,8 @@ copy_rest:
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;
@@ -1170,7 +1174,9 @@ copy_rest:
}
list->head = 0;
ret += len;
- goto copy_rest;
+ count -= len;
+ if (count > 0)
+ goto copy_rest;
}
}