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tee-supplicant: Allow to control RPMB emulation during runtime #354

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tee-supplicant: Allow to control RPMB emulation during runtime #354

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2 changes: 1 addition & 1 deletion tee-supplicant/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ include ../config.mk

OUT_DIR := $(OO)/tee-supplicant

# Emulate RPMB ioctl's by default
# Support RPMB emulation by default (--rpmb-emu command line argument)
RPMB_EMU ?= 1

.PHONY: all tee-supplicant clean
Expand Down
74 changes: 47 additions & 27 deletions tee-supplicant/src/rpmb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
*/

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/types.h>
#include <linux/mmc/ioctl.h>
Expand All @@ -46,8 +47,6 @@
#ifdef RPMB_EMU
#include <stdarg.h>
#include "hmac_sha2.h"
#else
#include <errno.h>
#endif

/*
Expand Down Expand Up @@ -139,18 +138,6 @@ static pthread_mutex_t rpmb_mutex = PTHREAD_MUTEX_INITIALIZER;
/* Maximum number of commands used in a multiple ioc command request */
#define RPMB_MAX_IOC_MULTI_CMDS 3

#ifndef RPMB_EMU

#define IOCTL(fd, request, ...) \
({ \
int ret; \
ret = ioctl((fd), (request), ##__VA_ARGS__); \
if (ret < 0) \
EMSG("ioctl ret=%d errno=%d", ret, errno); \
ret; \
})


/* Open and/or return file descriptor to RPMB partition of device dev_id */
static int mmc_rpmb_fd(uint16_t dev_id)
{
Expand Down Expand Up @@ -389,9 +376,9 @@ static bool remap_rpmb_dev_id(uint16_t dev_id, uint16_t *ndev_id)
return found;
}

#else /* RPMB_EMU */
#ifdef RPMB_EMU

#define IOCTL(fd, request, ...) ioctl_emu((fd), (request), ##__VA_ARGS__)
#define use_rpmb_emu() supplicant_params.rpmb_emu

/* Emulated rel_wr_sec_c value (reliable write size, *256 bytes) */
#define EMU_RPMB_REL_WR_SEC_C 1
Expand Down Expand Up @@ -609,7 +596,7 @@ static void ioctl_emu_read_ctr(struct rpmb_emu *mem,
frm->op_result = compute_hmac(mem, frm, 1);
}

static uint32_t read_cid(uint16_t dev_id, uint8_t *cid)
static uint32_t read_cid_emu(uint16_t dev_id, uint8_t *cid)
{
/* Taken from an actual eMMC chip */
static const uint8_t test_cid[] = {
Expand Down Expand Up @@ -747,36 +734,46 @@ static int ioctl_emu(int fd, unsigned long request, ...)
return res;
}

static int mmc_rpmb_fd(uint16_t dev_id)
static int mmc_rpmb_fd_emu(uint16_t dev_id)
{
(void)dev_id;

/* Any value != -1 will do in test mode */
return 0;
}

static TEEC_Result read_size_mult(uint16_t dev_id, uint8_t *value)
static TEEC_Result read_size_mult_emu(uint16_t dev_id, uint8_t *value)
{
(void)dev_id;

*value = EMU_RPMB_SIZE_MULT;
return TEEC_SUCCESS;
}

static TEEC_Result read_rel_wr_sec_c(uint16_t dev_id, uint8_t *value)
static TEEC_Result read_rel_wr_sec_c_emu(uint16_t dev_id, uint8_t *value)
{
(void)dev_id;

*value = EMU_RPMB_REL_WR_SEC_C;
return TEEC_SUCCESS;
}

static bool remap_rpmb_dev_id(uint16_t dev_id, uint16_t *ndev_id)
static bool remap_rpmb_dev_id_emu(uint16_t dev_id, uint16_t *ndev_id)
{
*ndev_id = dev_id;
return true;
}

#else /* !RPMB_EMU */

#define use_rpmb_emu() (0)
#define read_cid_emu(dev_id, cid) (TEEC_ERROR_GENERIC)
#define ioctl_emu(fd, request, ...) (-1)
#define mmc_rpmb_fd_emu(dev_id) (-1)
#define read_size_mult_emu(dev_id, value) (TEEC_ERROR_GENERIC)
#define read_rel_wr_sec_c_emu(dev_id, value) (TEEC_ERROR_GENERIC)
#define remap_rpmb_dev_id_emu(dev_id, ndev_id) (false)

#endif /* RPMB_EMU */

static inline void set_mmc_io_cmd(struct mmc_ioc_cmd *cmd, unsigned int blocks,
Expand Down Expand Up @@ -890,7 +887,13 @@ static uint32_t rpmb_data_req(int fd, struct rpmb_data_frame *req_frm,
goto out;
}

st = IOCTL(fd, MMC_IOC_MULTI_CMD, mcmd);
if (use_rpmb_emu()) {
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Not sure it is very helpful to modify all the call sites to test for emu enabled. In this particular case we could define a ioctl wrapper for example do_ioctl() which would call either ioctl() or ioctl_emu().

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We don't have multiple call sites for those, that's why I left the if-else there and didn't add another level of wrappers.

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Ah yes, I see what you mean. Please disregard my comment then.

st = ioctl_emu(fd, MMC_IOC_MULTI_CMD, mcmd);
} else {
st = ioctl(fd, MMC_IOC_MULTI_CMD, mcmd);
if (st < 0)
EMSG("ioctl ret=%d errno=%d", st, errno);
}
if (st < 0)
res = TEEC_ERROR_GENERIC;

Expand All @@ -906,16 +909,25 @@ static uint32_t rpmb_get_dev_info(uint16_t dev_id, struct rpmb_dev_info *info)
uint8_t rpmb_size_mult = 0;
uint8_t rel_wr_sec_c = 0;

res = read_cid(dev_id, info->cid);
if (use_rpmb_emu())
res = read_cid_emu(dev_id, info->cid);
else
res = read_cid(dev_id, info->cid);
if (res != TEEC_SUCCESS)
return res;

res = read_size_mult(dev_id, &rpmb_size_mult);
if (use_rpmb_emu())
res = read_size_mult_emu(dev_id, &rpmb_size_mult);
else
res = read_size_mult(dev_id, &rpmb_size_mult);
if (res != TEEC_SUCCESS)
return res;
info->rpmb_size_mult = rpmb_size_mult;

res = read_rel_wr_sec_c(dev_id, &rel_wr_sec_c);
if (use_rpmb_emu())
res = read_rel_wr_sec_c_emu(dev_id, &rel_wr_sec_c);
else
res = read_rel_wr_sec_c(dev_id, &rel_wr_sec_c);
if (res != TEEC_SUCCESS)
return res;
info->rel_wr_sec_c = rel_wr_sec_c;
Expand All @@ -938,19 +950,27 @@ static uint32_t rpmb_process_request_unlocked(void *req, size_t req_size,
size_t rsp_nfrm = 0;
uint16_t dev_id = 0;
uint32_t res = 0;
bool success;
int fd = 0;

if (req_size < sizeof(*sreq))
return TEEC_ERROR_BAD_PARAMETERS;

if (!remap_rpmb_dev_id(sreq->dev_id, &dev_id))
if (use_rpmb_emu())
success = remap_rpmb_dev_id_emu(sreq->dev_id, &dev_id);
else
success = remap_rpmb_dev_id(sreq->dev_id, &dev_id);
if (!success)
return TEEC_ERROR_ITEM_NOT_FOUND;

switch (sreq->cmd) {
case RPMB_CMD_DATA_REQ:
req_nfrm = (req_size - sizeof(struct rpmb_req)) / 512;
rsp_nfrm = rsp_size / 512;
fd = mmc_rpmb_fd(dev_id);
if (use_rpmb_emu())
fd = mmc_rpmb_fd_emu(dev_id);
else
fd = mmc_rpmb_fd(dev_id);
if (fd < 0)
return TEEC_ERROR_BAD_PARAMETERS;
res = rpmb_data_req(fd, RPMB_REQ_DATA(req), req_nfrm, rsp,
Expand Down
13 changes: 12 additions & 1 deletion tee-supplicant/src/tee_supplicant.c
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Expand Up @@ -493,6 +493,9 @@ static int usage(int status)
fprintf(stderr, "\t-h, --help: this help\n");
fprintf(stderr, "\t-d, --daemonize: run as a daemon (fork and return "
"after child has opened the TEE device or on error)\n");
#ifdef RPMB_EMU
fprintf(stderr, "\t-e, --rpmb-emu: use emulated RPMB\n");
#endif
fprintf(stderr, "\t-f, --fs-parent-path: secure fs parent path [%s]\n",
supplicant_params.fs_parent_path);
fprintf(stderr, "\t-t, --ta-dir: TAs dirname under %s [%s]\n", TEEC_LOAD_PATH,
Expand Down Expand Up @@ -808,14 +811,17 @@ int main(int argc, char *argv[])
/* long name | has argument | flag | short value */
{ "help", no_argument, 0, 'h' },
{ "daemonize", no_argument, 0, 'd' },
#ifdef RPMB_EMU
{ "rpmb-emu", no_argument, 0, 'e' },
#endif
{ "fs-parent-path", required_argument, 0, 'f' },
{ "ta-dir", required_argument, 0, 't' },
{ "plugin-path", required_argument, 0, 'p' },
{ "rpmb-cid", required_argument, 0, 'r' },
{ 0, 0, 0, 0 }
};

while ((opt = getopt_long(argc, argv, "hdf:t:p:r:",
while ((opt = getopt_long(argc, argv, "hdef:t:p:r:",
long_options, &long_index )) != -1) {
switch (opt) {
case 'h' :
Expand All @@ -824,6 +830,11 @@ int main(int argc, char *argv[])
case 'd':
daemonize = true;
break;
#ifdef RPMB_EMU
case 'e':
supplicant_params.rpmb_emu = true;
break;
#endif
case 'f':
supplicant_params.fs_parent_path = optarg;
break;
Expand Down
3 changes: 3 additions & 0 deletions tee-supplicant/src/tee_supplicant.h
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Expand Up @@ -44,6 +44,9 @@ struct tee_supplicant_params {
const char *plugin_load_path;
const char *fs_parent_path;
const char *rpmb_cid;
#ifdef RPMB_EMU
bool rpmb_emu;
#endif
};

extern struct tee_supplicant_params supplicant_params;
Expand Down