| Message ID | 20240705074339.633717-1-lee@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 6d3c721e686ea6c59e18289b400cc95c76e927e0 |
| Headers | show |
| Series | [1/1] usb: gadget: configfs: Prevent OOB read/write in usb_string_copy() | expand |
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index ce3cfa1f36f51..0e7c1e947c0a0 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -115,9 +115,12 @@ 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;
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. Signed-off-by: Lee Jones <lee@kernel.org> --- drivers/usb/gadget/configfs.c | 3 +++ 1 file changed, 3 insertions(+)