Commit c6dbf554 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman
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USB: cdc-acm: signedness fix

Fix bogus assignment of "unsigned char *" to "char *":  preserve
unsignedness.  These values are used directly as descriptor lengths
when iterating through the buffer, so this *could* cause oddness
that potentially includes oopsing.  (IMO not likely, except as
part of a malicious device...)

Fix the bogus warning in CDC ACM which highlighted this problem
(by showing a negative descriptor type).  It uses the undesirable
legacy err() for something that's not even an error; switch to
use dev_dbg, and show descriptor types in hex notation to match
the convention for such codes.
Signed-off-by: default avatarDavid Brownell <>
Acked-by: default avatarOliver Neukum <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 08177e12
......@@ -804,7 +804,7 @@ static int acm_probe (struct usb_interface *intf,
struct usb_cdc_union_desc *union_header = NULL;
struct usb_cdc_country_functional_desc *cfd = NULL;
char *buffer = intf->altsetting->extra;
unsigned char *buffer = intf->altsetting->extra;
int buflen = intf->altsetting->extralen;
struct usb_interface *control_interface;
struct usb_interface *data_interface;
......@@ -881,9 +881,13 @@ static int acm_probe (struct usb_interface *intf,
if ((call_management_function & 3) != 3)
err("This device cannot do calls on its own. It is no modem.");
err("Ignoring extra header, type %d, length %d", buffer[2], buffer[0]);
/* there are LOTS more CDC descriptors that
* could legitimately be found here.
dev_dbg(&intf->dev, "Ignoring descriptor: "
"type %02x, length %d\n",
buffer[2], buffer[0]);
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