Re: [PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value

From: Greg KH
Date: Wed Jan 12 2022 - 02:08:52 EST

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In reply to: Pawel Laszczak: "[PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value"
Next in thread: Pawel Laszczak: "RE: [PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value"
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On Wed, Jan 12, 2022 at 06:32:37AM +0100, Pawel Laszczak wrote:
> From: Pawel Laszczak <pawell@xxxxxxxxxxx>
>
> Variable ret in function cdnsp_decode_trb is initialized but not
> used. To fix this compiler warning patch adds checking whether the
> data buffer has not been overflowed.
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
> ---
> drivers/usb/cdns3/cdnsp-debug.h | 305 ++++++++++++++++----------------
> 1 file changed, 154 insertions(+), 151 deletions(-)
>
> diff --git a/drivers/usb/cdns3/cdnsp-debug.h b/drivers/usb/cdns3/cdnsp-debug.h
> index a8776df2d4e0..f0ca865cce2a 100644
> --- a/drivers/usb/cdns3/cdnsp-debug.h
> +++ b/drivers/usb/cdns3/cdnsp-debug.h
> @@ -182,208 +182,211 @@ static inline const char *cdnsp_decode_trb(char *str, size_t size, u32 field0,
> int ep_id = TRB_TO_EP_INDEX(field3) - 1;
> int type = TRB_FIELD_TO_TYPE(field3);
> unsigned int ep_num;
> - int ret = 0;
> + int ret;
> u32 temp;
>
> ep_num = DIV_ROUND_UP(ep_id, 2);
>
> switch (type) {
> case TRB_LINK:
> - ret += snprintf(str, size,
> - "LINK %08x%08x intr %ld type '%s' flags %c:%c:%c:%c",
> - field1, field0, GET_INTR_TARGET(field2),
> - cdnsp_trb_type_string(type),
> - field3 & TRB_IOC ? 'I' : 'i',
> - field3 & TRB_CHAIN ? 'C' : 'c',
> - field3 & TRB_TC ? 'T' : 't',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "LINK %08x%08x intr %ld type '%s' flags %c:%c:%c:%c",
> + field1, field0, GET_INTR_TARGET(field2),
> + cdnsp_trb_type_string(type),
> + field3 & TRB_IOC ? 'I' : 'i',
> + field3 & TRB_CHAIN ? 'C' : 'c',
> + field3 & TRB_TC ? 'T' : 't',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_TRANSFER:
> case TRB_COMPLETION:
> case TRB_PORT_STATUS:
> case TRB_HC_EVENT:
> - ret += snprintf(str, size,
> - "ep%d%s(%d) type '%s' TRB %08x%08x status '%s'"
> - " len %ld slot %ld flags %c:%c",
> - ep_num, ep_id % 2 ? "out" : "in",
> - TRB_TO_EP_INDEX(field3),
> - cdnsp_trb_type_string(type), field1, field0,
> - cdnsp_trb_comp_code_string(GET_COMP_CODE(field2)),
> - EVENT_TRB_LEN(field2), TRB_TO_SLOT_ID(field3),
> - field3 & EVENT_DATA ? 'E' : 'e',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "ep%d%s(%d) type '%s' TRB %08x%08x status '%s'"
> + " len %ld slot %ld flags %c:%c",
> + ep_num, ep_id % 2 ? "out" : "in",
> + TRB_TO_EP_INDEX(field3),
> + cdnsp_trb_type_string(type), field1, field0,
> + cdnsp_trb_comp_code_string(GET_COMP_CODE(field2)),
> + EVENT_TRB_LEN(field2), TRB_TO_SLOT_ID(field3),
> + field3 & EVENT_DATA ? 'E' : 'e',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_MFINDEX_WRAP:
> - ret += snprintf(str, size, "%s: flags %c",
> - cdnsp_trb_type_string(type),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size, "%s: flags %c",
> + cdnsp_trb_type_string(type),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_SETUP:
> - ret += snprintf(str, size,
> - "type '%s' bRequestType %02x bRequest %02x "
> - "wValue %02x%02x wIndex %02x%02x wLength %d "
> - "length %ld TD size %ld intr %ld Setup ID %ld "
> - "flags %c:%c:%c",
> - cdnsp_trb_type_string(type),
> - field0 & 0xff,
> - (field0 & 0xff00) >> 8,
> - (field0 & 0xff000000) >> 24,
> - (field0 & 0xff0000) >> 16,
> - (field1 & 0xff00) >> 8,
> - field1 & 0xff,
> - (field1 & 0xff000000) >> 16 |
> - (field1 & 0xff0000) >> 16,
> - TRB_LEN(field2), GET_TD_SIZE(field2),
> - GET_INTR_TARGET(field2),
> - TRB_SETUPID_TO_TYPE(field3),
> - field3 & TRB_IDT ? 'D' : 'd',
> - field3 & TRB_IOC ? 'I' : 'i',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "type '%s' bRequestType %02x bRequest %02x "
> + "wValue %02x%02x wIndex %02x%02x wLength %d "
> + "length %ld TD size %ld intr %ld Setup ID %ld "
> + "flags %c:%c:%c",
> + cdnsp_trb_type_string(type),
> + field0 & 0xff,
> + (field0 & 0xff00) >> 8,
> + (field0 & 0xff000000) >> 24,
> + (field0 & 0xff0000) >> 16,
> + (field1 & 0xff00) >> 8,
> + field1 & 0xff,
> + (field1 & 0xff000000) >> 16 |
> + (field1 & 0xff0000) >> 16,
> + TRB_LEN(field2), GET_TD_SIZE(field2),
> + GET_INTR_TARGET(field2),
> + TRB_SETUPID_TO_TYPE(field3),
> + field3 & TRB_IDT ? 'D' : 'd',
> + field3 & TRB_IOC ? 'I' : 'i',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_DATA:
> - ret += snprintf(str, size,
> - "type '%s' Buffer %08x%08x length %ld TD size %ld "
> - "intr %ld flags %c:%c:%c:%c:%c:%c:%c",
> - cdnsp_trb_type_string(type),
> - field1, field0, TRB_LEN(field2),
> - GET_TD_SIZE(field2),
> - GET_INTR_TARGET(field2),
> - field3 & TRB_IDT ? 'D' : 'i',
> - field3 & TRB_IOC ? 'I' : 'i',
> - field3 & TRB_CHAIN ? 'C' : 'c',
> - field3 & TRB_NO_SNOOP ? 'S' : 's',
> - field3 & TRB_ISP ? 'I' : 'i',
> - field3 & TRB_ENT ? 'E' : 'e',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "type '%s' Buffer %08x%08x length %ld TD size %ld "
> + "intr %ld flags %c:%c:%c:%c:%c:%c:%c",
> + cdnsp_trb_type_string(type),
> + field1, field0, TRB_LEN(field2),
> + GET_TD_SIZE(field2),
> + GET_INTR_TARGET(field2),
> + field3 & TRB_IDT ? 'D' : 'i',
> + field3 & TRB_IOC ? 'I' : 'i',
> + field3 & TRB_CHAIN ? 'C' : 'c',
> + field3 & TRB_NO_SNOOP ? 'S' : 's',
> + field3 & TRB_ISP ? 'I' : 'i',
> + field3 & TRB_ENT ? 'E' : 'e',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_STATUS:
> - ret += snprintf(str, size,
> - "Buffer %08x%08x length %ld TD size %ld intr"
> - "%ld type '%s' flags %c:%c:%c:%c",
> - field1, field0, TRB_LEN(field2),
> - GET_TD_SIZE(field2),
> - GET_INTR_TARGET(field2),
> - cdnsp_trb_type_string(type),
> - field3 & TRB_IOC ? 'I' : 'i',
> - field3 & TRB_CHAIN ? 'C' : 'c',
> - field3 & TRB_ENT ? 'E' : 'e',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "Buffer %08x%08x length %ld TD size %ld intr"
> + "%ld type '%s' flags %c:%c:%c:%c",
> + field1, field0, TRB_LEN(field2),
> + GET_TD_SIZE(field2),
> + GET_INTR_TARGET(field2),
> + cdnsp_trb_type_string(type),
> + field3 & TRB_IOC ? 'I' : 'i',
> + field3 & TRB_CHAIN ? 'C' : 'c',
> + field3 & TRB_ENT ? 'E' : 'e',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_NORMAL:
> case TRB_ISOC:
> case TRB_EVENT_DATA:
> case TRB_TR_NOOP:
> - ret += snprintf(str, size,
> - "type '%s' Buffer %08x%08x length %ld "
> - "TD size %ld intr %ld "
> - "flags %c:%c:%c:%c:%c:%c:%c:%c:%c",
> - cdnsp_trb_type_string(type),
> - field1, field0, TRB_LEN(field2),
> - GET_TD_SIZE(field2),
> - GET_INTR_TARGET(field2),
> - field3 & TRB_BEI ? 'B' : 'b',
> - field3 & TRB_IDT ? 'T' : 't',
> - field3 & TRB_IOC ? 'I' : 'i',
> - field3 & TRB_CHAIN ? 'C' : 'c',
> - field3 & TRB_NO_SNOOP ? 'S' : 's',
> - field3 & TRB_ISP ? 'I' : 'i',
> - field3 & TRB_ENT ? 'E' : 'e',
> - field3 & TRB_CYCLE ? 'C' : 'c',
> - !(field3 & TRB_EVENT_INVALIDATE) ? 'V' : 'v');
> + ret = snprintf(str, size,
> + "type '%s' Buffer %08x%08x length %ld "
> + "TD size %ld intr %ld "
> + "flags %c:%c:%c:%c:%c:%c:%c:%c:%c",
> + cdnsp_trb_type_string(type),
> + field1, field0, TRB_LEN(field2),
> + GET_TD_SIZE(field2),
> + GET_INTR_TARGET(field2),
> + field3 & TRB_BEI ? 'B' : 'b',
> + field3 & TRB_IDT ? 'T' : 't',
> + field3 & TRB_IOC ? 'I' : 'i',
> + field3 & TRB_CHAIN ? 'C' : 'c',
> + field3 & TRB_NO_SNOOP ? 'S' : 's',
> + field3 & TRB_ISP ? 'I' : 'i',
> + field3 & TRB_ENT ? 'E' : 'e',
> + field3 & TRB_CYCLE ? 'C' : 'c',
> + !(field3 & TRB_EVENT_INVALIDATE) ? 'V' : 'v');
> break;
> case TRB_CMD_NOOP:
> case TRB_ENABLE_SLOT:
> - ret += snprintf(str, size, "%s: flags %c",
> - cdnsp_trb_type_string(type),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size, "%s: flags %c",
> + cdnsp_trb_type_string(type),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_DISABLE_SLOT:
> - ret += snprintf(str, size, "%s: slot %ld flags %c",
> - cdnsp_trb_type_string(type),
> - TRB_TO_SLOT_ID(field3),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size, "%s: slot %ld flags %c",
> + cdnsp_trb_type_string(type),
> + TRB_TO_SLOT_ID(field3),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_ADDR_DEV:
> - ret += snprintf(str, size,
> - "%s: ctx %08x%08x slot %ld flags %c:%c",
> - cdnsp_trb_type_string(type), field1, field0,
> - TRB_TO_SLOT_ID(field3),
> - field3 & TRB_BSR ? 'B' : 'b',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "%s: ctx %08x%08x slot %ld flags %c:%c",
> + cdnsp_trb_type_string(type), field1, field0,
> + TRB_TO_SLOT_ID(field3),
> + field3 & TRB_BSR ? 'B' : 'b',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_CONFIG_EP:
> - ret += snprintf(str, size,
> - "%s: ctx %08x%08x slot %ld flags %c:%c",
> - cdnsp_trb_type_string(type), field1, field0,
> - TRB_TO_SLOT_ID(field3),
> - field3 & TRB_DC ? 'D' : 'd',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "%s: ctx %08x%08x slot %ld flags %c:%c",
> + cdnsp_trb_type_string(type), field1, field0,
> + TRB_TO_SLOT_ID(field3),
> + field3 & TRB_DC ? 'D' : 'd',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_EVAL_CONTEXT:
> - ret += snprintf(str, size,
> - "%s: ctx %08x%08x slot %ld flags %c",
> - cdnsp_trb_type_string(type), field1, field0,
> - TRB_TO_SLOT_ID(field3),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "%s: ctx %08x%08x slot %ld flags %c",
> + cdnsp_trb_type_string(type), field1, field0,
> + TRB_TO_SLOT_ID(field3),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_RESET_EP:
> case TRB_HALT_ENDPOINT:
> case TRB_FLUSH_ENDPOINT:
> - ret += snprintf(str, size,
> - "%s: ep%d%s(%d) ctx %08x%08x slot %ld flags %c",
> - cdnsp_trb_type_string(type),
> - ep_num, ep_id % 2 ? "out" : "in",
> - TRB_TO_EP_INDEX(field3), field1, field0,
> - TRB_TO_SLOT_ID(field3),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "%s: ep%d%s(%d) ctx %08x%08x slot %ld flags %c",
> + cdnsp_trb_type_string(type),
> + ep_num, ep_id % 2 ? "out" : "in",
> + TRB_TO_EP_INDEX(field3), field1, field0,
> + TRB_TO_SLOT_ID(field3),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_STOP_RING:
> - ret += snprintf(str, size,
> - "%s: ep%d%s(%d) slot %ld sp %d flags %c",
> - cdnsp_trb_type_string(type),
> - ep_num, ep_id % 2 ? "out" : "in",
> - TRB_TO_EP_INDEX(field3),
> - TRB_TO_SLOT_ID(field3),
> - TRB_TO_SUSPEND_PORT(field3),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "%s: ep%d%s(%d) slot %ld sp %d flags %c",
> + cdnsp_trb_type_string(type),
> + ep_num, ep_id % 2 ? "out" : "in",
> + TRB_TO_EP_INDEX(field3),
> + TRB_TO_SLOT_ID(field3),
> + TRB_TO_SUSPEND_PORT(field3),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_SET_DEQ:
> - ret += snprintf(str, size,
> - "%s: ep%d%s(%d) deq %08x%08x stream %ld slot %ld flags %c",
> - cdnsp_trb_type_string(type),
> - ep_num, ep_id % 2 ? "out" : "in",
> - TRB_TO_EP_INDEX(field3), field1, field0,
> - TRB_TO_STREAM_ID(field2),
> - TRB_TO_SLOT_ID(field3),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size,
> + "%s: ep%d%s(%d) deq %08x%08x stream %ld slot %ld flags %c",
> + cdnsp_trb_type_string(type),
> + ep_num, ep_id % 2 ? "out" : "in",
> + TRB_TO_EP_INDEX(field3), field1, field0,
> + TRB_TO_STREAM_ID(field2),
> + TRB_TO_SLOT_ID(field3),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_RESET_DEV:
> - ret += snprintf(str, size, "%s: slot %ld flags %c",
> - cdnsp_trb_type_string(type),
> - TRB_TO_SLOT_ID(field3),
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + ret = snprintf(str, size, "%s: slot %ld flags %c",
> + cdnsp_trb_type_string(type),
> + TRB_TO_SLOT_ID(field3),
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> case TRB_ENDPOINT_NRDY:
> - temp = TRB_TO_HOST_STREAM(field2);
> -
> - ret += snprintf(str, size,
> - "%s: ep%d%s(%d) H_SID %x%s%s D_SID %lx flags %c:%c",
> - cdnsp_trb_type_string(type),
> - ep_num, ep_id % 2 ? "out" : "in",
> - TRB_TO_EP_INDEX(field3), temp,
> - temp == STREAM_PRIME_ACK ? "(PRIME)" : "",
> - temp == STREAM_REJECTED ? "(REJECTED)" : "",
> - TRB_TO_DEV_STREAM(field0),
> - field3 & TRB_STAT ? 'S' : 's',
> - field3 & TRB_CYCLE ? 'C' : 'c');
> + temp = TRB_TO_HOST_STREAM(field2);
> +
> + ret = snprintf(str, size,
> + "%s: ep%d%s(%d) H_SID %x%s%s D_SID %lx flags %c:%c",
> + cdnsp_trb_type_string(type),
> + ep_num, ep_id % 2 ? "out" : "in",
> + TRB_TO_EP_INDEX(field3), temp,
> + temp == STREAM_PRIME_ACK ? "(PRIME)" : "",
> + temp == STREAM_REJECTED ? "(REJECTED)" : "",
> + TRB_TO_DEV_STREAM(field0),
> + field3 & TRB_STAT ? 'S' : 's',
> + field3 & TRB_CYCLE ? 'C' : 'c');
> break;
> default:
> - ret += snprintf(str, size,
> - "type '%s' -> raw %08x %08x %08x %08x",
> - cdnsp_trb_type_string(type),
> - field0, field1, field2, field3);
> + ret = snprintf(str, size,
> + "type '%s' -> raw %08x %08x %08x %08x",
> + cdnsp_trb_type_string(type),
> + field0, field1, field2, field3);
> }
>
> + if (ret >= size)
> + pr_info("CDNSP: buffer overflowed.\n");

"info"?

If the buffer overflows, was it properly truncated? Or did we just
crash something else by passing on an overflowed buffer?

thanks,

greg k-h

Next message: Jagan Teki: "Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge"
Previous message: Greg KH: "Re: [PATCH v4 1/1] ucsi_ccg: Check DEV_INT bit only when starting CCG4"
In reply to: Pawel Laszczak: "[PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value"
Next in thread: Pawel Laszczak: "RE: [PATCH] usb: cdnsp: fix cdnsp_decode_trb function to properly handle ret value"
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