6.12-stable review patch. If anyone has any objections, please let me know.
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From: Foster Snowhill forst@pen.gy
commit 2a9a196429e98fcc64078366c2679bc40aba5466 upstream.
Introduce an rx_error label to reduce repetitions in the header signature checks.
Store wDatagramIndex and wDatagramLength after endianness conversion to avoid repeated le16_to_cpu() calls.
Rewrite the loop to return on a null trailing DPE, which is required by the CDC NCM spec. In case it is missing, fall through to rx_error.
This change does not fix any particular issue. Its purpose is to simplify a subsequent commit that fixes a potential OoB read by limiting the maximum amount of processed DPEs.
Cc: stable@vger.kernel.org # 6.5.x Signed-off-by: Foster Snowhill forst@pen.gy Reviewed-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/usb/ipheth.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-)
--- a/drivers/net/usb/ipheth.c +++ b/drivers/net/usb/ipheth.c @@ -213,9 +213,9 @@ static int ipheth_rcvbulk_callback_ncm(s struct usb_cdc_ncm_ndp16 *ncm0; struct usb_cdc_ncm_dpe16 *dpe; struct ipheth_device *dev; + u16 dg_idx, dg_len; int retval = -EINVAL; char *buf; - int len;
dev = urb->context;
@@ -227,39 +227,43 @@ static int ipheth_rcvbulk_callback_ncm(s ncmh = urb->transfer_buffer; if (ncmh->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH16_SIGN) || /* On iOS, NDP16 directly follows NTH16 */ - ncmh->wNdpIndex != cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16))) { - dev->net->stats.rx_errors++; - return retval; - } + ncmh->wNdpIndex != cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16))) + goto rx_error;
ncm0 = urb->transfer_buffer + sizeof(struct usb_cdc_ncm_nth16); - if (ncm0->dwSignature != cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN)) { - dev->net->stats.rx_errors++; - return retval; - } + if (ncm0->dwSignature != cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN)) + goto rx_error;
dpe = ncm0->dpe16; - while (le16_to_cpu(dpe->wDatagramIndex) != 0 && - le16_to_cpu(dpe->wDatagramLength) != 0) { - if (le16_to_cpu(dpe->wDatagramIndex) < IPHETH_NCM_HEADER_SIZE || - le16_to_cpu(dpe->wDatagramIndex) >= urb->actual_length || - le16_to_cpu(dpe->wDatagramLength) > urb->actual_length - - le16_to_cpu(dpe->wDatagramIndex)) { + while (true) { + dg_idx = le16_to_cpu(dpe->wDatagramIndex); + dg_len = le16_to_cpu(dpe->wDatagramLength); + + /* Null DPE must be present after last datagram pointer entry + * (3.3.1 USB CDC NCM spec v1.0) + */ + if (dg_idx == 0 && dg_len == 0) + return 0; + + if (dg_idx < IPHETH_NCM_HEADER_SIZE || + dg_idx >= urb->actual_length || + dg_len > urb->actual_length - dg_idx) { dev->net->stats.rx_length_errors++; return retval; }
- buf = urb->transfer_buffer + le16_to_cpu(dpe->wDatagramIndex); - len = le16_to_cpu(dpe->wDatagramLength); + buf = urb->transfer_buffer + dg_idx;
- retval = ipheth_consume_skb(buf, len, dev); + retval = ipheth_consume_skb(buf, dg_len, dev); if (retval != 0) return retval;
dpe++; }
- return 0; +rx_error: + dev->net->stats.rx_errors++; + return retval; }
static void ipheth_rcvbulk_callback(struct urb *urb)