[PATCH 5.14 16/23] xhci: fix unsafe memory usage in xhci tracing

From: Greg Kroah-Hartman
Date: Fri Sep 10 2021 - 08:31:13 EST

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From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>

commit cbf286e8ef8337308c259ff5b9ce2e74d403be5a upstream.

Removes static char buffer usage in the following decode functions:
xhci_decode_trb()
xhci_decode_ptortsc()

Caller must provide a buffer to use.
In tracing use __get_str() as recommended to pass buffer.

Minor chanes are needed in xhci debugfs code as these functions are also
used there. Changes include moving XHCI_MSG_MAX definititon from
xhci-trace.h to xhci.h

Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210820123503.2605901-2-mathias.nyman@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-debugfs.c | 6 +++-
drivers/usb/host/xhci-trace.h | 8 +++---
drivers/usb/host/xhci.h | 52 +++++++++++++++++++++-------------------
3 files changed, 36 insertions(+), 30 deletions(-)

--- a/drivers/usb/host/xhci-debugfs.c
+++ b/drivers/usb/host/xhci-debugfs.c
@@ -198,12 +198,13 @@ static void xhci_ring_dump_segment(struc
int i;
dma_addr_t dma;
union xhci_trb *trb;
+ char str[XHCI_MSG_MAX];

for (i = 0; i < TRBS_PER_SEGMENT; i++) {
trb = &seg->trbs[i];
dma = seg->dma + i * sizeof(*trb);
seq_printf(s, "%pad: %s\n", &dma,
- xhci_decode_trb(le32_to_cpu(trb->generic.field[0]),
+ xhci_decode_trb(str, XHCI_MSG_MAX, le32_to_cpu(trb->generic.field[0]),
le32_to_cpu(trb->generic.field[1]),
le32_to_cpu(trb->generic.field[2]),
le32_to_cpu(trb->generic.field[3])));
@@ -345,9 +346,10 @@ static int xhci_portsc_show(struct seq_f
{
struct xhci_port *port = s->private;
u32 portsc;
+ char str[XHCI_MSG_MAX];

portsc = readl(port->addr);
- seq_printf(s, "%s\n", xhci_decode_portsc(portsc));
+ seq_printf(s, "%s\n", xhci_decode_portsc(str, portsc));

return 0;
}
--- a/drivers/usb/host/xhci-trace.h
+++ b/drivers/usb/host/xhci-trace.h
@@ -25,8 +25,6 @@
#include "xhci.h"
#include "xhci-dbgcap.h"

-#define XHCI_MSG_MAX 500
-
DECLARE_EVENT_CLASS(xhci_log_msg,
TP_PROTO(struct va_format *vaf),
TP_ARGS(vaf),
@@ -122,6 +120,7 @@ DECLARE_EVENT_CLASS(xhci_log_trb,
__field(u32, field1)
__field(u32, field2)
__field(u32, field3)
+ __dynamic_array(char, str, XHCI_MSG_MAX)
),
TP_fast_assign(
__entry->type = ring->type;
@@ -131,7 +130,7 @@ DECLARE_EVENT_CLASS(xhci_log_trb,
__entry->field3 = le32_to_cpu(trb->field[3]);
),
TP_printk("%s: %s", xhci_ring_type_string(__entry->type),
- xhci_decode_trb(__entry->field0, __entry->field1,
+ xhci_decode_trb(__get_str(str), XHCI_MSG_MAX, __entry->field0, __entry->field1,
__entry->field2, __entry->field3)
)
);
@@ -526,6 +525,7 @@ DECLARE_EVENT_CLASS(xhci_log_portsc,
TP_STRUCT__entry(
__field(u32, portnum)
__field(u32, portsc)
+ __dynamic_array(char, str, XHCI_MSG_MAX)
),
TP_fast_assign(
__entry->portnum = portnum;
@@ -533,7 +533,7 @@ DECLARE_EVENT_CLASS(xhci_log_portsc,
),
TP_printk("port-%d: %s",
__entry->portnum,
- xhci_decode_portsc(__entry->portsc)
+ xhci_decode_portsc(__get_str(str), __entry->portsc)
)
);

--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -22,6 +22,9 @@
#include "xhci-ext-caps.h"
#include "pci-quirks.h"

+/* max buffer size for trace and debug messages */
+#define XHCI_MSG_MAX 500
+
/* xHCI PCI Configuration Registers */
#define XHCI_SBRN_OFFSET (0x60)

@@ -2235,15 +2238,14 @@ static inline char *xhci_slot_state_stri
}
}

-static inline const char *xhci_decode_trb(u32 field0, u32 field1, u32 field2,
- u32 field3)
+static inline const char *xhci_decode_trb(char *str, size_t size,
+ u32 field0, u32 field1, u32 field2, u32 field3)
{
- static char str[256];
int type = TRB_FIELD_TO_TYPE(field3);

switch (type) {
case TRB_LINK:
- sprintf(str,
+ snprintf(str, size,
"LINK %08x%08x intr %d type '%s' flags %c:%c:%c:%c",
field1, field0, GET_INTR_TARGET(field2),
xhci_trb_type_string(type),
@@ -2260,7 +2262,7 @@ static inline const char *xhci_decode_tr
case TRB_HC_EVENT:
case TRB_DEV_NOTE:
case TRB_MFINDEX_WRAP:
- sprintf(str,
+ snprintf(str, size,
"TRB %08x%08x status '%s' len %d slot %d ep %d type '%s' flags %c:%c",
field1, field0,
xhci_trb_comp_code_string(GET_COMP_CODE(field2)),
@@ -2273,7 +2275,8 @@ static inline const char *xhci_decode_tr

break;
case TRB_SETUP:
- sprintf(str, "bRequestType %02x bRequest %02x wValue %02x%02x wIndex %02x%02x wLength %d length %d TD size %d intr %d type '%s' flags %c:%c:%c",
+ snprintf(str, size,
+ "bRequestType %02x bRequest %02x wValue %02x%02x wIndex %02x%02x wLength %d length %d TD size %d intr %d type '%s' flags %c:%c:%c",
field0 & 0xff,
(field0 & 0xff00) >> 8,
(field0 & 0xff000000) >> 24,
@@ -2290,7 +2293,8 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_DATA:
- sprintf(str, "Buffer %08x%08x length %d TD size %d intr %d type '%s' flags %c:%c:%c:%c:%c:%c:%c",
+ snprintf(str, size,
+ "Buffer %08x%08x length %d TD size %d intr %d type '%s' flags %c:%c:%c:%c:%c:%c:%c",
field1, field0, TRB_LEN(field2), GET_TD_SIZE(field2),
GET_INTR_TARGET(field2),
xhci_trb_type_string(type),
@@ -2303,7 +2307,8 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_STATUS:
- sprintf(str, "Buffer %08x%08x length %d TD size %d intr %d type '%s' flags %c:%c:%c:%c",
+ snprintf(str, size,
+ "Buffer %08x%08x length %d TD size %d intr %d type '%s' flags %c:%c:%c:%c",
field1, field0, TRB_LEN(field2), GET_TD_SIZE(field2),
GET_INTR_TARGET(field2),
xhci_trb_type_string(type),
@@ -2316,7 +2321,7 @@ static inline const char *xhci_decode_tr
case TRB_ISOC:
case TRB_EVENT_DATA:
case TRB_TR_NOOP:
- sprintf(str,
+ snprintf(str, size,
"Buffer %08x%08x length %d TD size %d intr %d type '%s' flags %c:%c:%c:%c:%c:%c:%c:%c",
field1, field0, TRB_LEN(field2), GET_TD_SIZE(field2),
GET_INTR_TARGET(field2),
@@ -2333,21 +2338,21 @@ static inline const char *xhci_decode_tr

case TRB_CMD_NOOP:
case TRB_ENABLE_SLOT:
- sprintf(str,
+ snprintf(str, size,
"%s: flags %c",
xhci_trb_type_string(type),
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_DISABLE_SLOT:
case TRB_NEG_BANDWIDTH:
- sprintf(str,
+ snprintf(str, size,
"%s: slot %d flags %c",
xhci_trb_type_string(type),
TRB_TO_SLOT_ID(field3),
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_ADDR_DEV:
- sprintf(str,
+ snprintf(str, size,
"%s: ctx %08x%08x slot %d flags %c:%c",
xhci_trb_type_string(type),
field1, field0,
@@ -2356,7 +2361,7 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_CONFIG_EP:
- sprintf(str,
+ snprintf(str, size,
"%s: ctx %08x%08x slot %d flags %c:%c",
xhci_trb_type_string(type),
field1, field0,
@@ -2365,7 +2370,7 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_EVAL_CONTEXT:
- sprintf(str,
+ snprintf(str, size,
"%s: ctx %08x%08x slot %d flags %c",
xhci_trb_type_string(type),
field1, field0,
@@ -2373,7 +2378,7 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_RESET_EP:
- sprintf(str,
+ snprintf(str, size,
"%s: ctx %08x%08x slot %d ep %d flags %c:%c",
xhci_trb_type_string(type),
field1, field0,
@@ -2394,7 +2399,7 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_SET_DEQ:
- sprintf(str,
+ snprintf(str, size,
"%s: deq %08x%08x stream %d slot %d ep %d flags %c",
xhci_trb_type_string(type),
field1, field0,
@@ -2405,14 +2410,14 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_RESET_DEV:
- sprintf(str,
+ snprintf(str, size,
"%s: slot %d flags %c",
xhci_trb_type_string(type),
TRB_TO_SLOT_ID(field3),
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_FORCE_EVENT:
- sprintf(str,
+ snprintf(str, size,
"%s: event %08x%08x vf intr %d vf id %d flags %c",
xhci_trb_type_string(type),
field1, field0,
@@ -2421,14 +2426,14 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_SET_LT:
- sprintf(str,
+ snprintf(str, size,
"%s: belt %d flags %c",
xhci_trb_type_string(type),
TRB_TO_BELT(field3),
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_GET_BW:
- sprintf(str,
+ snprintf(str, size,
"%s: ctx %08x%08x slot %d speed %d flags %c",
xhci_trb_type_string(type),
field1, field0,
@@ -2437,7 +2442,7 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
case TRB_FORCE_HEADER:
- sprintf(str,
+ snprintf(str, size,
"%s: info %08x%08x%08x pkt type %d roothub port %d flags %c",
xhci_trb_type_string(type),
field2, field1, field0 & 0xffffffe0,
@@ -2446,7 +2451,7 @@ static inline const char *xhci_decode_tr
field3 & TRB_CYCLE ? 'C' : 'c');
break;
default:
- sprintf(str,
+ snprintf(str, size,
"type '%s' -> raw %08x %08x %08x %08x",
xhci_trb_type_string(type),
field0, field1, field2, field3);
@@ -2569,9 +2574,8 @@ static inline const char *xhci_portsc_li
return "Unknown";
}

-static inline const char *xhci_decode_portsc(u32 portsc)
+static inline const char *xhci_decode_portsc(char *str, u32 portsc)
{
- static char str[256];
int ret;

ret = sprintf(str, "%s %s %s Link:%s PortSpeed:%d ",

Next message: Greg Kroah-Hartman: "[PATCH 5.14 17/23] xhci: Fix failure to give back some cached cancelled URBs."
Previous message: Greg Kroah-Hartman: "[PATCH 5.14 15/23] xhci: fix even more unsafe memory usage in xhci tracing"
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Next in thread: Greg Kroah-Hartman: "[PATCH 5.14 17/23] xhci: Fix failure to give back some cached cancelled URBs."
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