From f199e966e1da09385b3a822b60220c3e7dad5d15 Mon Sep 17 00:00:00 2001

From: Yannick Cote <ycote@redhat.com>

Date: Wed, 7 Dec 2022 13:51:50 -0500

Subject: [KPATCH CVE-2022-2964] kpatch fixes for CVE-2022-2964

Kernels:

4.18.0-425.3.1.el8

Kpatch-MR: https://gitlab.com/redhat/prdsc/rhel/src/kpatch/rhel-8/-/merge_requests/65

Approved-by: Joe Lawrence (@joe.lawrence)

Changes since last build:

arches: x86_64 ppc64le

ax88179_178a.o: changed function: ax88179_rx_fixup

---------------------------

Modifications: none

commit f12daa92e8162af22fa80f7a69c2b7069a600f24

Author: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Date:   Wed Nov 23 17:38:38 2022 +0100

    net: usb: ax88179_178a: Fix out-of-bounds accesses in RX fixup

    Bugzilla: https://bugzilla.redhat.com/2142724

    CVE: CVE-2022-2964

    commit 57bc3d3ae8c14df3ceb4e17d26ddf9eeab304581

    Author: Jann Horn <jannh@google.com>

    Date:   Wed Jan 26 14:14:52 2022 +0100

        net: usb: ax88179_178a: Fix out-of-bounds accesses in RX fixup

        ax88179_rx_fixup() contains several out-of-bounds accesses that can be

        triggered by a malicious (or defective) USB device, in particular:

         - The metadata array (hdr_off..hdr_off+2*pkt_cnt) can be out of bounds,

           causing OOB reads and (on big-endian systems) OOB endianness flips.

         - A packet can overlap the metadata array, causing a later OOB

           endianness flip to corrupt data used by a cloned SKB that has already

           been handed off into the network stack.

         - A packet SKB can be constructed whose tail is far beyond its end,

           causing out-of-bounds heap data to be considered part of the SKB's

           data.

        I have tested that this can be used by a malicious USB device to send a

        bogus ICMPv6 Echo Request and receive an ICMPv6 Echo Reply in response

        that contains random kernel heap data.

        It's probably also possible to get OOB writes from this on a

        little-endian system somehow - maybe by triggering skb_cow() via IP

        options processing -, but I haven't tested that.

        Fixes: e2ca90c276e1 ("ax88179_178a: ASIX AX88179_178A USB 3.0/2.0 to gigabit ethernet adapter driver")

        Cc: stable@kernel.org

        Signed-off-by: Jann Horn <jannh@google.com>

        Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

commit 065aec7252fd7a895103db717faf36984cd3ce35

Author: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Date:   Wed Nov 23 17:38:39 2022 +0100

    net: usb: ax88179_178a: Fix packet receiving

    Bugzilla: https://bugzilla.redhat.com/2142724

    CVE: CVE-2022-2964

    commit f8ebb3ac881b17712e1d5967c97ab1806b16d3d6

    Author: Jose Alonso <joalonsof@gmail.com>

    Date:   Tue Jun 28 12:13:02 2022 -0300

        net: usb: ax88179_178a: Fix packet receiving

        This patch corrects packet receiving in ax88179_rx_fixup.

        - problem observed:

          ifconfig shows allways a lot of 'RX Errors' while packets

          are received normally.

          This occurs because ax88179_rx_fixup does not recognise properly

          the usb urb received.

          The packets are normally processed and at the end, the code exits

          with 'return 0', generating RX Errors.

          (pkt_cnt==-2 and ptk_hdr over field rx_hdr trying to identify

           another packet there)

          This is a usb urb received by "tcpdump -i usbmon2 -X" on a

          little-endian CPU:

          0x0000:  eeee f8e3 3b19 87a0 94de 80e3 daac 0800

                   ^         packet 1 start (pkt_len = 0x05ec)

                   ^^^^      IP alignment pseudo header

                        ^    ethernet packet start

                   last byte ethernet packet   v

                   padding (8-bytes aligned)     vvvv vvvv

          0x05e0:  c92d d444 1420 8a69 83dd 272f e82b 9811

          0x05f0:  eeee f8e3 3b19 87a0 94de 80e3 daac 0800

          ...      ^ packet 2

          0x0be0:  eeee f8e3 3b19 87a0 94de 80e3 daac 0800

          ...

          0x1130:  9d41 9171 8a38 0ec5 eeee f8e3 3b19 87a0

          ...

          0x1720:  8cfc 15ff 5e4c e85c eeee f8e3 3b19 87a0

          ...

          0x1d10:  ecfa 2a3a 19ab c78c eeee f8e3 3b19 87a0

          ...

          0x2070:  eeee f8e3 3b19 87a0 94de 80e3 daac 0800

          ...      ^ packet 7

          0x2120:  7c88 4ca5 5c57 7dcc 0d34 7577 f778 7e0a

          0x2130:  f032 e093 7489 0740 3008 ec05 0000 0080

                                       ====1==== ====2====

                   hdr_off             ^

                   pkt_len = 0x05ec         ^^^^

                   AX_RXHDR_*=0x00830  ^^^^   ^

                   pkt_len = 0                        ^^^^

                   AX_RXHDR_DROP_ERR=0x80000000  ^^^^   ^

          0x2140:  3008 ec05 0000 0080 3008 5805 0000 0080

          0x2150:  3008 ec05 0000 0080 3008 ec05 0000 0080

          0x2160:  3008 5803 0000 0080 3008 c800 0000 0080

                   ===11==== ===12==== ===13==== ===14====

          0x2170:  0000 0000 0e00 3821

                             ^^^^ ^^^^ rx_hdr

                             ^^^^      pkt_cnt=14

                                  ^^^^ hdr_off=0x2138

                   ^^^^ ^^^^           padding

          The dump shows that pkt_cnt is the number of entrys in the

          per-packet metadata. It is "2 * packet count".

          Each packet have two entrys. The first have a valid

          value (pkt_len and AX_RXHDR_*) and the second have a

          dummy-header 0x80000000 (pkt_len=0 with AX_RXHDR_DROP_ERR).

          Why exists dummy-header for each packet?!?

          My guess is that this was done probably to align the

          entry for each packet to 64-bits and maintain compatibility

          with old firmware.

          There is also a padding (0x00000000) before the rx_hdr to

          align the end of rx_hdr to 64-bit.

          Note that packets have a alignment of 64-bits (8-bytes).

          This patch assumes that the dummy-header and the last

          padding are optional. So it preserves semantics and

          recognises the same valid packets as the current code.

          This patch was made using only the dumpfile information and

          tested with only one device:

          0b95:1790 ASIX Electronics Corp. AX88179 Gigabit Ethernet

        Fixes: 57bc3d3ae8c1 ("net: usb: ax88179_178a: Fix out-of-bounds accesses in RX fixup")

        Fixes: e2ca90c276e1 ("ax88179_178a: ASIX AX88179_178A USB 3.0/2.0 to gigabit ethernet adapter driver")

        Signed-off-by: Jose Alonso <joalonsof@gmail.com>

        Acked-by: Paolo Abeni <pabeni@redhat.com>

        Link: https://lore.kernel.org/r/d6970bb04bf67598af4d316eaeb1792040b18cfd.camel@gmail.com

        Signed-off-by: Paolo Abeni <pabeni@redhat.com>

    Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Signed-off-by: Yannick Cote <ycote@redhat.com>

---

 drivers/net/usb/ax88179_178a.c | 113 +++++++++++++++++++++++++--------

 1 file changed, 87 insertions(+), 26 deletions(-)

diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c

index 2eb02808812c..a4896f396c7c 100644

--- a/drivers/net/usb/ax88179_178a.c

+++ b/drivers/net/usb/ax88179_178a.c

@@ -1477,58 +1477,119 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct sk_buff *skb)

 	u16 hdr_off;

 	u32 *pkt_hdr;

-	/* This check is no longer done by usbnet */

-	if (skb->len < dev->net->hard_header_len)

+	/* At the end of the SKB, there's a header telling us how many packets

+	 * are bundled into this buffer and where we can find an array of

+	 * per-packet metadata (which contains elements encoded into u16).

+	 */

+

+	/* SKB contents for current firmware:

+	 *   <packet 1> <padding>

+	 *   ...

+	 *   <packet N> <padding>

+	 *   <per-packet metadata entry 1> <dummy header>

+	 *   ...

+	 *   <per-packet metadata entry N> <dummy header>

+	 *   <padding2> <rx_hdr>

+	 *

+	 * where:

+	 *   <packet N> contains pkt_len bytes:

+	 *		2 bytes of IP alignment pseudo header

+	 *		packet received

+	 *   <per-packet metadata entry N> contains 4 bytes:

+	 *		pkt_len and fields AX_RXHDR_*

+	 *   <padding>	0-7 bytes to terminate at

+	 *		8 bytes boundary (64-bit).

+	 *   <padding2> 4 bytes to make rx_hdr terminate at

+	 *		8 bytes boundary (64-bit)

+	 *   <dummy-header> contains 4 bytes:

+	 *		pkt_len=0 and AX_RXHDR_DROP_ERR

+	 *   <rx-hdr>	contains 4 bytes:

+	 *		pkt_cnt and hdr_off (offset of

+	 *		  <per-packet metadata entry 1>)

+	 *

+	 * pkt_cnt is number of entrys in the per-packet metadata.

+	 * In current firmware there is 2 entrys per packet.

+	 * The first points to the packet and the

+	 *  second is a dummy header.

+	 * This was done probably to align fields in 64-bit and

+	 *  maintain compatibility with old firmware.

+	 * This code assumes that <dummy header> and <padding2> are

+	 *  optional.

+	 */

+

+	if (skb->len < 4)

 		return 0;

-

 	skb_trim(skb, skb->len - 4);

 	rx_hdr = get_unaligned_le32(skb_tail_pointer(skb));

-

 	pkt_cnt = (u16)rx_hdr;

 	hdr_off = (u16)(rx_hdr >> 16);

+

+	if (pkt_cnt == 0)

+		return 0;

+

+	/* Make sure that the bounds of the metadata array are inside the SKB

+	 * (and in front of the counter at the end).

+	 */

+	if (pkt_cnt * 4 + hdr_off > skb->len)

+		return 0;

 	pkt_hdr = (u32 *)(skb->data + hdr_off);

-	while (pkt_cnt--) {

+	/* Packets must not overlap the metadata array */

+	skb_trim(skb, hdr_off);

+

+	for (; pkt_cnt > 0; pkt_cnt--, pkt_hdr++) {

+		u16 pkt_len_plus_padd;

 		u16 pkt_len;

 		le32_to_cpus(pkt_hdr);

 		pkt_len = (*pkt_hdr >> 16) & 0x1fff;

+		pkt_len_plus_padd = (pkt_len + 7) & 0xfff8;

+

+		/* Skip dummy header used for alignment

+		 */

+		if (pkt_len == 0)

+			continue;

+

+		if (pkt_len_plus_padd > skb->len)

+			return 0;

 		/* Check CRC or runt packet */

-		if ((*pkt_hdr & AX_RXHDR_CRC_ERR) ||

-		    (*pkt_hdr & AX_RXHDR_DROP_ERR)) {

-			skb_pull(skb, (pkt_len + 7) & 0xFFF8);

-			pkt_hdr++;

+		if ((*pkt_hdr & (AX_RXHDR_CRC_ERR | AX_RXHDR_DROP_ERR)) ||

+		    pkt_len < 2 + ETH_HLEN) {

+			dev->net->stats.rx_errors++;

+			skb_pull(skb, pkt_len_plus_padd);

 			continue;

 		}

-		if (pkt_cnt == 0) {

-			skb->len = pkt_len;

+		/* last packet */

+		if (pkt_len_plus_padd == skb->len) {

+			skb_trim(skb, pkt_len);

+

 			/* Skip IP alignment pseudo header */

 			skb_pull(skb, 2);

-			skb_set_tail_pointer(skb, skb->len);

-			skb->truesize = pkt_len + sizeof(struct sk_buff);

+

+			skb->truesize = SKB_TRUESIZE(pkt_len_plus_padd);

 			ax88179_rx_checksum(skb, pkt_hdr);

 			return 1;

 		}

 		ax_skb = skb_clone(skb, GFP_ATOMIC);

-		if (ax_skb) {

-			ax_skb->len = pkt_len;

-			/* Skip IP alignment pseudo header */

-			skb_pull(ax_skb, 2);

-			skb_set_tail_pointer(ax_skb, ax_skb->len);

-			ax_skb->truesize = pkt_len + sizeof(struct sk_buff);

-			ax88179_rx_checksum(ax_skb, pkt_hdr);

-			usbnet_skb_return(dev, ax_skb);

-		} else {

+		if (!ax_skb)

 			return 0;

-		}

+		skb_trim(ax_skb, pkt_len);

+

+		/* Skip IP alignment pseudo header */

+		skb_pull(ax_skb, 2);

+

+		skb->truesize = pkt_len_plus_padd +

+				SKB_DATA_ALIGN(sizeof(struct sk_buff));

+		ax88179_rx_checksum(ax_skb, pkt_hdr);

+		usbnet_skb_return(dev, ax_skb);

-		skb_pull(skb, (pkt_len + 7) & 0xFFF8);

-		pkt_hdr++;

+		skb_pull(skb, pkt_len_plus_padd);

 	}

-	return 1;

+

+	return 0;

 }

 static struct sk_buff *

-- 

2.38.1