【发布时间】：2011-11-21 16:14:58
【问题描述】：
我正在尝试在我的 fuse 文件系统中使用 ioctl 来利用 LTO5 设备的硬件加密。应该很简单，用cdb设置io_hdr：
0xB5, 0x20, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x34, 0x00, 0x00
并根据所选算法提供关键页面。当我执行 SG_IO ioctl 时，我返回 0，SCSI 感觉全为 0。
现在，这就是奇怪的地方。写入设备的数据永远不会加密。我将磁带切换到另一个驱动器并进行 SCSI 读取，数据都是明文形式。
因此下一步是执行 SCSI SPIN 命令以查看 SPOUT 命令是否已执行，即使所有返回都表明已执行。在 SPOUT 之后，我立即为安全状态页面 (0x20) 发送一个 SPIN：
0xA2, 0x20, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf8, 0x00, 0x00
同样，从 SG_IO ioctl 返回值 0 和全零感。但是我返回的页面是我放入驱动器的 SPOUT 关键页面。我确信这不是来自驱动器，因为它具有我发送的密钥，这绝对是 SCSI 规范，不，不。顺便说一句，我对两个 SCSI 命令都使用了完全不同的缓冲区，并将 SPIN 页面设置为零只是为了更好的衡量。 sg 驱动程序正在提供此数据以响应 SPIN。
谁能解释一下这种行为？
Linux archive.xxxxx.xxx 2.6.18-274.7.1.el5 #1 SMP Thu Oct 20 16:21:01 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
sg3_utils-libs-1.25-5.el5
sgpio-1.2.0_10-2.el5
mt-st-0.9b-2.2.2
我正在向 /dev/sg5 发送 ioctl 命令：
[root@archive bin]# sg_inq /dev/sg5
standard INQUIRY:
PQual=0 Device_type=1 RMB=1 version=0x06 [SPC-4]
[AERC=0] [TrmTsk=0] NormACA=0 HiSUP=0 Resp_data_format=2
SCCS=0 ACC=0 TPGS=0 3PC=0 Protect=1 BQue=0
EncServ=0 MultiP=1 (VS=0) [MChngr=0] [ACKREQQ=0] Addr16=0
[RelAdr=0] WBus16=0 Sync=0 Linked=0 [TranDis=0] CmdQue=1
[SPI: Clocking=0x0 QAS=0 IUS=0]
length=70 (0x46) Peripheral device type: tape
Vendor identification: IBM
Product identification: ULTRIUM-HH5
Product revision level: BAKG
Unit serial number: 106xxxxxxxxxx
我发现 Linux ioctl 系统调用返回 SG_ERR_DID_ERROR [0x07] 在 sg_io_hdr_t 的 host_status 成员中的主机适配器中检测到内部错误。
setltokey.c 代码也在这里：http://www.circlesoft.com/setltokey.c
/*
setLTO4key: Set LTO4 Encryption Key
Copyright (c) 2008 Andrew Schretter <schrett@math.duke.edu>
Provided under GPL license
added clear encryption,
sense key and
error printouts - Gerard J. Cerchio <gjpc@circlesoft.com>
*/
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <scsi/sg.h>
#include <scsi/scsi.h>
#include <ctype.h>
#include <sys/ioctl.h>
#include <unistd.h>
#define SENSE_BUFF_LEN 96 /* from lto spec */
/*
* here is a sample key - create a file with these HEX digits:
4418AFCD046F2535B2E996123CE7DE3D418A15915A091C4BA12BDC85D4069A77
*/
/*
* A good sg_io_hdr_t reference: http://tldp.org/HOWTO/SCSI-Generic-HOWTO/sg_io_hdr_t.html
*/
/* Print a hexadecimal dump of a block of data */
void hexdump(void *data, int size)
{
unsigned char *p = data;
unsigned char c;
int n;
char bytestr[4] = {0};
char addrstr[10] = {0};
char hexstr[ 16*3 + 5] = {0};
char charstr[16*1 + 5] = {0};
for(n=1;n<=size;n++) {
if (n%16 == 1) {
/* store address for this line */
snprintf(addrstr, sizeof(addrstr), "%.4x",
((unsigned int)p-(unsigned int)data) );
}
c = *p;
if (isalnum(c) == 0) {
c = '.';
}
/* store hex str (for left side) */
snprintf(bytestr, sizeof(bytestr), "%02X ", *p);
strncat(hexstr, bytestr, sizeof(hexstr)-strlen(hexstr)-1);
/* store char str (for right side) */
snprintf(bytestr, sizeof(bytestr), "%c", c);
strncat(charstr, bytestr, sizeof(charstr)-strlen(charstr)-1);
if(n%16 == 0) {
/* line completed */
printf(" [%4.4s] %-49.49s %s\n", addrstr, hexstr, charstr);
hexstr[0] = 0;
charstr[0] = 0;
} else if(n%8 == 0) {
/* half line: add whitespaces */
strncat(hexstr, " ", sizeof(hexstr)-strlen(hexstr)-1);
}
p++; /* next byte */
}
if (strlen(hexstr) > 0) {
/* print rest of buffer if not empty */
printf(" [%4.4s] %-49.49s %s\n", addrstr, hexstr, charstr);
}
}
/* Send a SCSI command block and display the result. */
void do_read_command(int fd, char *desc, unsigned char *cmd, int len)
{
unsigned char sense[SENSE_BUFF_LEN];
memset( sense, 0, SENSE_BUFF_LEN );
sg_io_hdr_t io;
unsigned char buf[512];
memset(buf, 0, sizeof(buf));
memset(&io, 0, sizeof(io));
io.interface_id = 'S';
io.cmd_len = len;
io.mx_sb_len = 0;
io.dxfer_direction = SG_DXFER_FROM_DEV;
io.dxfer_len = sizeof(buf);
io.dxferp = buf;
io.cmdp = cmd;
printf("Command: %s\n", desc);
hexdump(cmd, len);
if (ioctl(fd, SG_IO, &io) < 0) {
printf("Error: %s\n", strerror(errno));
return;
}
if ( io.sb_len_wr ){
printf("Sense\n");
hexdump( sense, SENSE_BUFF_LEN );
}
else
printf( "No Sense\n" );
if ((io.info & SG_INFO_OK_MASK) != SG_INFO_OK) {
printf("Failed with info 0x%02x mask status 0x%02x msg status 0x%02x host status 0x%02x driver status 0x%02x\n", io.info, io.masked_status, io.msg_status, io.host_status, io.driver_status );
return;
}
len = io.dxfer_len - io.resid;
printf("Response: %d %s\n", len, (len == 1) ? "byte" : "bytes");
hexdump(buf, len);
}
void do_write_command(int fd, char *desc, unsigned char *cmd, int len, char *data_desc, unsigned char *data, int datalen)
{
unsigned char sense[SENSE_BUFF_LEN];
memset( sense, 0, SENSE_BUFF_LEN );
sg_io_hdr_t io;
memset(&io, 0, sizeof(io));
io.interface_id = 'S';
io.cmd_len = len;
io.mx_sb_len = SENSE_BUFF_LEN;
io.dxfer_direction = SG_DXFER_TO_DEV;
io.dxfer_len = datalen;
io.dxferp = data;
io.cmdp = cmd;
io.sbp = sense;
printf("Command: %s\n", desc);
hexdump(cmd, len);
printf("Data: %s\n", data_desc);
hexdump(data, datalen);
if (ioctl(fd, SG_IO, &io) < 0) {
printf("Error: %s\n", strerror(errno));
return;
}
if ( io.sb_len_wr ){
printf("Sense\n");
hexdump( sense, SENSE_BUFF_LEN );
}
else
printf( "No Sense\n" );
if ((io.info & SG_INFO_OK_MASK) != SG_INFO_OK) {
printf("Failed with info 0x%02x mask status 0x%02x msg status 0x%02x host status 0x%02x driver status 0x%02x\n", io.info, io.masked_status, io.msg_status, io.host_status, io.driver_status );
return;
}
len = io.dxfer_len - io.resid;
printf("Response: %d %s\n", len, (len == 1) ? "byte" : "bytes");
//hexdump(buf, len);
}
struct {
char *description;
int len;
unsigned char cmd[16];
} commands[] = {
{ "SCSI Inquiry", 6,
{ 0x12, 0x00, 0x00, 0x00, 0xFF, 0x00 } },
{ "SCSI SPOUT Set Encryption Key", 12,
{ 0xb5, 0x20, 0x00, 0x10, 0x00, 0x00,
0x00, 0x00, 0x00, 0x34, 0x00, 0x00 } },
{ "SCSI SPIN Read Status", 12,
{ 0xa2, 0x20, 0x00, 0x20, 0x00, 0x00,
0xff, 0xff, 0xff, 0xff, 0x00, 0x00 } },
{ NULL, 0, { 0 } },
};
struct {
char *description;
int len;
unsigned char cmd[64];
} data[] = {
{ "SCSI SPOUT Send Encryption Key Page", 52,
{ 0x00, 0x10, 0x00, 0x30, 0x40, 0x00,
0x02, 0x03, 0x01, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x20,
} },
{ "SCSI SPOUT Clear Encryption Mode Page", 52,
{ 0x00, 0x10, 0x00, 0x30, 0x40, 0x00,
0x00, 0x00, 0x01, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x20,
} },
{ NULL, 0, { 0 } },
};
int main(int argc, char **argv)
{
FILE *fd2;
int fd;
int i = 0;
if (argc < 2) {
fprintf(stderr, "usage: %s /dev/sda < <keyfile.txt> | clear >\n", *argv);
return 1;
}
if ((fd = open(argv[1], O_RDWR)) < 0) {
perror(argv[1]);
return 1;
}
if ((ioctl(fd, SG_GET_VERSION_NUM, &i) < 0) || (i < 30000)) {
fprintf(stderr,"%s is not a sg device\n", argv[1]);
close(fd);
return 1;
}
printf("Opened %s\n", argv[1]);
/* Send query command */
do_read_command(fd, commands[0].description, commands[0].cmd, commands[0].len);
if(argc > 2) {
if ( strcasecmp( argv[2], "clear" ) == 0 ) {
do_write_command(fd, commands[1].description, commands[1].cmd, commands[1].len, data[1].description, data[1].cmd, data[1].len);
}
else
{
if ((fd2 = fopen(argv[2], "r")) < 0) {
perror(argv[2]);
return 1;
}
for (i = 0; i < 32; i++) {
if( fscanf(fd2, "%2x ", (unsigned int *) &data[0].cmd[i + 20]) != 1 ) {
fprintf(stderr, "Keyfile Error reading %s\n", argv[2]);
return 1;
}
}
fclose(fd2);
/* Set Encryption key*/
do_write_command(fd, commands[1].description, commands[1].cmd, commands[1].len, data[0].description, data[0].cmd, data[0].len);
}
}
/* Query encryption status */
do_read_command(fd, commands[2].description, commands[2].cmd, commands[2].len);
close(fd);
return 0;
}
【问题讨论】：
-
StackOverflow 用于编程问题。这属于超级用户。请阅读常见问题解答：stackoverflow.com/faq
-
这是在特定设备上使用 Linux 调用 ioctl 的编程问题。
标签： encryption linux-device-driver ioctl scsi