UPSTREAM: usb: gadget: configfs: Prevent OOB read/write in usb_string_copy() commit 6d3c721e686ea6c59e18289b400cc95c76e927e0 upstream. Userspace provided string 's' could trivially have the length zero. Left unchecked this will firstly result in an OOB read in the form `if (str[0 - 1] == '\n') followed closely by an OOB write in the form `str[0 - 1] = '\0'`. There is already a validating check to catch strings that are too long. Let's supply an additional check for invalid strings that are too short. Bug: 346754046 Signed-off-by: Lee Jones <lee@kernel.org> Cc: stable <stable@kernel.org> Link: https://lore.kernel.org/r/20240705074339.633717-1-lee@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (cherry picked from commit d1205033e912f9332c1dbefa812e6ceb0575ce0a) Signed-off-by: Lee Jones <joneslee@google.com> Change-Id: Id9a34f3e5495aef0d2a800a1386210f4d9fa8116
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index d99cdb9..808dcad 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c
@@ -148,9 +148,12 @@ static int usb_string_copy(const char *s, char **s_copy) int ret; char *str; char *copy = *s_copy; + ret = strlen(s); if (ret > USB_MAX_STRING_LEN) return -EOVERFLOW; + if (ret < 1) + return -EINVAL; if (copy) { str = copy;