Re: [RFC PATCH 1/1] mmc-utils: Support-sending-eMMC-5.0-FFU

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Avi,
Thanks for posting these - I look forward to seeing this functionality
available in mmc-utils (and kernel as needed).

Comments as usual inline.

I've added Gwendal/Kees to CC to comment on security issues of this
proposal. See notes below.


On Sun, Feb 9, 2014 at 1:08 AM, Avi Shchislowski
<Avi.Shchislowski@xxxxxxxxxxx> wrote:
>   The mmc-utils was modified to invoke eMMC5.0 Field Firmware Update (FFU) process in mmc driver
>   New command was add: "do_emmc50_ffu".
>
>   This patch depends on patch  mmc: Support-FFU-for-eMMC-v5.0 Committed by Avi Shchislowski <avi.shchislowski@xxxxxxxxxxx>
>
>   FFU will be done in two steps. Two new IOCTL codes will be sent to the driver in order to operate FFU code:
>     1.  FFU_DWONLOAD_OP (sent in ffu_download_image() function)

Any reason for the typo? DOWNLOAD maybe?
Shouldn't that be MMC_FFU_DOWNLOAD_OP to match the proposed kernel definition?

>         2.  FFU_INSTALL_OP (sent in ffu_install() function)

Ditto: MMC_FFU_INSTALL_OP

>
>
> Signed-off-by: Avi Shchislowski <avi.shchislowski@xxxxxxxxxxx>
> Signed-off-by: Alex Lemberg <alex.lemberg@xxxxxxxxxxx>
>
> diff --git a/mmc.c b/mmc.c
> index 926e92f..a01852d 100644
> --- a/mmc.c
> +++ b/mmc.c
> @@ -36,9 +36,9 @@ struct Command {
>                                    if >= 0, number of arguments,
>                                    if < 0, _minimum_ number of arguments */
>         char    *verb;          /* verb */
> -       char    *help;          /* help lines; from the 2nd line onward they
> +       char    *help;          /* help lines; from the 2nd line onward they
>                                     are automatically indented */
> -        char    *adv_help;      /* advanced help message; from the 2nd line
> +        char    *adv_help;      /* advanced help message; from the 2nd line

Sorry, it's not obvious what changed here. Why is this included?

>                                     onward they are automatically indented */
>
>         /* the following fields are run-time filled by the program */ @@ -110,6 +110,11 @@ static struct Command commands[] = {
>                 "Send Sanitize command to the <device>.\nThis will delete the unmapped memory region of the device.",
>           NULL
>         },
> +       { do_emmc50_ffu, -2,
> +       "emmc50 ffu", "<image path> <device>\n"
> +         "run eMMC 5.0 Field firmware update.\n.",

Nit: This isn't "run". It's "download firmware to eMMC 5.0 compliant device".

> +         NULL
> +       },
>         { 0, 0, 0, 0 }
>  };
>
> @@ -362,7 +367,7 @@ static int parse_args(int argc, char **argv,
>                         matchcmd->verb, matchcmd->nargs);
>                         return -2;
>         }
> -
> +

I'm going to ignore white space mangle on this patch and assume you'll
ask if you need help using gmail to send patches using git send-email.

But the above isn't white space mangle caused by email - it's part of
this patch and I'm not seeing a difference in this <REDACTED> gmail
editor.

>          if (prepare_args( nargs_, args_, prgname, matchcmd )){
>                  fprintf(stderr, "ERROR: not enough memory\\n");
>                 return -20;
> diff --git a/mmc.h b/mmc.h
> index 9871d62..3be6db0 100644
> --- a/mmc.h
> +++ b/mmc.h
> @@ -80,6 +80,14 @@
>  #define BKOPS_ENABLE   (1<<0)
>
>  /*
> + * sector size
> +*/
> +#define CARD_BLOCK_SIZE        512

sector size is advertised by the device. It could be either 512 or 4K bytes. No?

"7.4.17 NUMBER_OF_FW_SECTORS_CORRECTLY_PROGRAMMED [305-302]

The value is in terms of 512 Bytes or in multiple of eight 512Bytes
sectors (4KBytes) depending on the value of the DATA_SECTOR_SIZE field."

I don't think this should be hard coded to 512. And a few places I see
hard coded with "<< 9" will likely need to take this into account.


> +
> +#define FFU_DWONLOAD_OP        302
> +#define FFU_INSTALL_OP 303

These should match kernel definitions (complete name and value).

> +
> +/*
>   * EXT_CSD field definitions
>   */
>  #define EXT_CSD_HPI_SUPP               (1<<0)
> diff --git a/mmc_cmds.c b/mmc_cmds.c
> index b8afa74..24c4a6b 100644
> --- a/mmc_cmds.c
> +++ b/mmc_cmds.c
> @@ -1163,3 +1163,112 @@ int do_sanitize(int nargs, char **argv)
>
>  }
>
> +static int ffu_download_image(int fw_fd, int mmc_fd) {
> +       int ret = 0;
> +       struct mmc_ioc_cmd mmc_ioc_cmd;
> +       char data_buff[MMC_IOC_MAX_BYTES];
> +       int file_size;

This should be off_t type. See "man 2 lseek".

> +       int size;

This should be size_t type.  See "man 2 read".

> +       int data_length;

This should ssize_t type. See "man 2 read".

> +
> +       memset(data_buff, 0, sizeof(data_buff));
> +       /* get file size */
> +       file_size = lseek(fw_fd, 0, SEEK_END);

I'm wondering why lseek would be preferred over fstat().

> +       if (file_size < 0) {
> +               ret =  -1;
> +               perror("seek file error \n");
> +               goto exit;
> +       }
> +
> +       lseek(fw_fd, 0, SEEK_SET);
> +       do {
> +               size = (file_size > MMC_IOC_MAX_BYTES) ?
> +                               MMC_IOC_MAX_BYTES : file_size;
> +               /* Read FW data from file */
> +               data_length = read(fw_fd, data_buff, size);
> +               if (data_length == -1) {

Should this test data_length < size ?

> +                       ret = -1;
> +                       goto exit;
> +               }

Gwendal and Kees (CC'd) would prefer to send the file name to the
kernel as part of the ioctl and use existing udev mechanisms to
request the firmware.

This has some advantages for security which make it a lot harder to
"plant" the hacked firmware on devices. I'll let Gwendal and Kees
present the details of those ideas.

> +               /* prepare and send ioctl */
> +               memset(&mmc_ioc_cmd, 0, sizeof(mmc_ioc_cmd));
> +               mmc_ioc_cmd.opcode =  FFU_DWONLOAD_OP;
> +               mmc_ioc_cmd.blksz = CARD_BLOCK_SIZE;
> +               mmc_ioc_cmd.blocks = data_length / mmc_ioc_cmd.blksz;
> +               mmc_ioc_cmd.arg =  0;
> +               mmc_ioc_cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +               mmc_ioc_cmd.write_flag = 1;
> +               mmc_ioc_cmd_set_data(mmc_ioc_cmd, data_buff);
> +               ret = ioctl(mmc_fd, MMC_IOC_CMD, &mmc_ioc_cmd);
> +               if (ret) {
> +                       perror("ioctl FW download");
> +                       goto exit;
> +               }
> +
> +               file_size = file_size - size;
> +               printf("firmware file loading, remaining:   %d\n", file_size);
> +       } while (file_size > 0);
> +
> +exit:
> +
> +       return ret;
> +}
> +
> +static int ffu_install(int mmc_fd)
> +{
> +       int ret;
> +       struct mmc_ioc_cmd mmc_ioc_cmd;
> +
> +       memset(&mmc_ioc_cmd, 0, sizeof(mmc_ioc_cmd));
> +       mmc_ioc_cmd.opcode = FFU_INSTALL_OP;
> +       mmc_ioc_cmd.blksz = CARD_BLOCK_SIZE;
> +       mmc_ioc_cmd.blocks = 0;
> +       mmc_ioc_cmd.arg =  0;
> +       mmc_ioc_cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +       mmc_ioc_cmd.write_flag = 0;
> +       ret = ioctl(mmc_fd, MMC_IOC_CMD, &mmc_ioc_cmd);
> +       if (ret)
> +               perror("ioctl install");
> +
> +       printf("ffu_install ret %d \n", ret);
> +       return ret;
> +}
> +
> +int do_emmc50_ffu(int nargs, char **argv) {
> +       int fd, fw_fd, ret;
> +       char *device;
> +
> +       CHECK(nargs != 3, "Usage: ffu <image path> </path/to/mmcblkX> \n",
> +                               exit(1));
> +
> +       device = argv[2];
> +       fd = open(device, O_RDWR);
> +       if (fd < 0) {
> +               perror("open");
> +               exit(1);
> +       }
> +
> +       /* open eMMC5.0 firmware image file */
> +       fw_fd = open(argv[1], O_RDONLY);
> +       if (fw_fd < 0) {
> +               perror("open eMMC5.0 firmware file");
> +               ret = -1;

Don't want to return the errno value?

> +               goto exit;
> +       }
> +
> +       ret = ffu_download_image(fw_fd, fd);
> +       if (ret)
> +               goto exit;
> +
> +       ret = ffu_install(fd);
> +       if (ret)
> +               goto exit;
> +
> +exit:
> +       close(fd);
> +       close(fw_fd);
> +
> +       return ret;
> +}
> diff --git a/mmc_cmds.h b/mmc_cmds.h
> index f06cc10..77a6cb8 100644
> --- a/mmc_cmds.h
> +++ b/mmc_cmds.h
> @@ -28,3 +28,5 @@ int do_sanitize(int nargs, char **argv);  int do_status_get(int nargs, char **argv);  int do_enh_area_set(int nargs, char **argv);  int do_write_reliability_set(int nargs, char **argv);
> +int do_emmc50_ffu(int nargs, char **argv);
> +
> --
> 1.7.5.4
>
>
> Avi Shchislowski | Staff Software Engineer, MCS Embedded  | SanDisk | +972.09.763-2666| www.sandisk.com
>

cheers,
grant
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