| Message ID | 20200925125147.26943-16-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | vhost-user-rpmb (Replay Protected Memory Block) | expand |
On Fri, Sep 25, 2020 at 01:51:43PM +0100, Alex Bennée wrote: > With this command we are finally updating data to the backing store > and cycling the write_count and each successful write. We also include > the write count in all response frames as the spec is a little unclear > but the example test code expected it. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > --- > tools/vhost-user-rpmb/main.c | 111 +++++++++++++++++++++++++++++++++-- > 1 file changed, 105 insertions(+), 6 deletions(-) > > diff --git a/tools/vhost-user-rpmb/main.c b/tools/vhost-user-rpmb/main.c > index 88747c50fa44..a17c3b4bcc4e 100644 > --- a/tools/vhost-user-rpmb/main.c > +++ b/tools/vhost-user-rpmb/main.c > @@ -62,6 +62,7 @@ enum { > #define KiB (1UL << 10) > #define MAX_RPMB_SIZE (KiB * 128 * 256) > #define RPMB_KEY_MAC_SIZE 32 > +#define RPMB_BLOCK_SIZE 256 > > /* RPMB Request Types */ > #define VIRTIO_RPMB_REQ_PROGRAM_KEY 0x0001 > @@ -100,7 +101,7 @@ struct virtio_rpmb_config { > struct virtio_rpmb_frame { > uint8_t stuff[196]; > uint8_t key_mac[RPMB_KEY_MAC_SIZE]; > - uint8_t data[256]; > + uint8_t data[RPMB_BLOCK_SIZE]; > uint8_t nonce[16]; > /* remaining fields are big-endian */ > uint32_t write_counter; > @@ -124,6 +125,7 @@ typedef struct VuRpmb { > uint8_t last_nonce[16]; > uint16_t last_result; > uint16_t last_reqresp; > + uint16_t last_address; > uint32_t write_count; > } VuRpmb; > > @@ -239,17 +241,30 @@ vrpmb_set_config(VuDev *dev, const uint8_t *data, > * which itself uses a 3 clause BSD chunk of code. > */ > > +static const int rpmb_frame_dlen = (sizeof(struct virtio_rpmb_frame) - > + offsetof(struct virtio_rpmb_frame, data)); > + > static void vrpmb_update_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) > { > hmac_sha256_ctx ctx; > - static const int dlen = (sizeof(struct virtio_rpmb_frame) - > - offsetof(struct virtio_rpmb_frame, data)); > > hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); > - hmac_sha256_update(&ctx, frm->data, dlen); > + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); > hmac_sha256_final(&ctx, &frm->key_mac[0], 32); > } > > +static bool vrpmb_verify_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) > +{ > + hmac_sha256_ctx ctx; > + uint8_t calculated_mac[RPMB_KEY_MAC_SIZE]; > + > + hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); > + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); > + hmac_sha256_final(&ctx, calculated_mac, RPMB_KEY_MAC_SIZE); > + > + return memcmp(calculated_mac, frm->key_mac, RPMB_KEY_MAC_SIZE) == 0; > I'd prefer using a constant time comparison function for this one instead of memcmp (regardless if it's used for simulation or not) to prevent eventual timing attacks. > +} > + > /* > * Handlers for individual control messages > */ > @@ -324,6 +339,82 @@ vrpmb_handle_get_write_counter(VuDev *dev, struct virtio_rpmb_frame *frame) > return resp; > } > > +/* > + * vrpmb_handle_write: > + * > + * We will report the success/fail on receipt of > + * VIRTIO_RPMB_REQ_RESULT_READ. Returns the number of extra frames > + * processed in the request. > + */ > +static int vrpmb_handle_write(VuDev *dev, struct virtio_rpmb_frame *frame) > +{ > + VuRpmb *r = container_of(dev, VuRpmb, dev.parent); > + int extra_frames = 0; > + uint16_t block_count = be16toh(frame->block_count); > + uint32_t write_counter = be32toh(frame->write_counter); > + size_t offset; > + > + r->last_reqresp = VIRTIO_RPMB_RESP_DATA_WRITE; > + r->last_address = be16toh(frame->address); > + offset = r->last_address * RPMB_BLOCK_SIZE; > + > + /* > + * Run the checks from: > + * 5.12.6.1.3 Device Requirements: Device Operation: Data Write > + */ > + if (!r->key) { > + g_warning("no key programmed"); > + r->last_result = VIRTIO_RPMB_RES_NO_AUTH_KEY; > + } else if (block_count == 0 || > + block_count > r->virtio_config.max_wr_cnt) { > + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; > + } else if (false /* what does an expired write counter mean? */) { > IIRC, the counter has room for a 32-bit value and the counter will never wrap around. So once the counter have reached max for uint32_t, then there is an additional bit set (permanently) in the operation result. I.e., writes are no longer possible once that has happened. That is probably what you're referring to here I suppose. > + r->last_result = VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED; > + } else if (offset > (r->virtio_config.capacity * (128 * KiB))) { > + r->last_result = VIRTIO_RPMB_RES_ADDR_FAILURE; > + } else if (!vrpmb_verify_mac_in_frame(r, frame)) { > + r->last_result = VIRTIO_RPMB_RES_AUTH_FAILURE; > + } else if (write_counter != r->write_count) { > + r->last_result = VIRTIO_RPMB_RES_COUNT_FAILURE; > + } else { > + int i; > + /* At this point we have a valid authenticated write request > + * so the counter can incremented and we can attempt to > + * update the backing device. > + */ > + r->write_count++; > + for (i = 0; i < block_count; i++) { > + void *blk = r->flash_map + offset; > + g_debug("%s: writing block %d", __func__, i); > + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_WRITE) != 0) { > + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; > + break; > + } > + memcpy(blk, frame[i].data, RPMB_BLOCK_SIZE); > + if (msync(blk, RPMB_BLOCK_SIZE, MS_SYNC) != 0) { > + g_warning("%s: failed to sync update", __func__); > + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; > + break; > + } > + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_READ) != 0) { > + g_warning("%s: failed to re-apply read protection", __func__); > + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; > + break; > + } > + offset += RPMB_BLOCK_SIZE; > + } > + r->last_result = VIRTIO_RPMB_RES_OK; > + extra_frames = i - 1; > + } > + > + g_info("%s: %s (%x, %d extra frames processed), write_count=%d", __func__, > + r->last_result == VIRTIO_RPMB_RES_OK ? "successful":"failed", > + r->last_result, extra_frames, r->write_count); > + > + return extra_frames; > +} > + > + > /* > * Return the result of the last message. This is only valid if the > * previous message was VIRTIO_RPMB_REQ_PROGRAM_KEY or > @@ -339,10 +430,14 @@ static struct virtio_rpmb_frame * vrpmb_handle_result_read(VuDev *dev) > g_info("%s: for request:%x result:%x", __func__, > r->last_reqresp, r->last_result); > > - if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY || > - r->last_reqresp == VIRTIO_RPMB_REQ_DATA_WRITE) { > + if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY) { > resp->result = htobe16(r->last_result); > resp->req_resp = htobe16(r->last_reqresp); > + } else if (r->last_reqresp == VIRTIO_RPMB_RESP_DATA_WRITE) { > + resp->result = htobe16(r->last_result); > + resp->req_resp = htobe16(r->last_reqresp); > + resp->write_counter = htobe32(r->write_count); > + resp->address = htobe16(r->last_address); > } else { > resp->result = htobe16(VIRTIO_RPMB_RES_GENERAL_FAILURE); > } > @@ -445,6 +540,10 @@ vrpmb_handle_ctrl(VuDev *dev, int qidx) > __func__); > } > break; > + case VIRTIO_RPMB_REQ_DATA_WRITE: > + /* we can have multiple blocks handled */ > + n += vrpmb_handle_write(dev, f); > + break; > default: > g_debug("un-handled request: %x", f->req_resp); > break; > -- > 2.20.1 >
Joakim Bech <joakim.bech@linaro.org> writes: > On Fri, Sep 25, 2020 at 01:51:43PM +0100, Alex Bennée wrote: >> With this command we are finally updating data to the backing store >> and cycling the write_count and each successful write. We also include >> the write count in all response frames as the spec is a little unclear >> but the example test code expected it. >> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> --- >> tools/vhost-user-rpmb/main.c | 111 +++++++++++++++++++++++++++++++++-- >> 1 file changed, 105 insertions(+), 6 deletions(-) >> >> diff --git a/tools/vhost-user-rpmb/main.c b/tools/vhost-user-rpmb/main.c >> index 88747c50fa44..a17c3b4bcc4e 100644 >> --- a/tools/vhost-user-rpmb/main.c >> +++ b/tools/vhost-user-rpmb/main.c >> @@ -62,6 +62,7 @@ enum { >> #define KiB (1UL << 10) >> #define MAX_RPMB_SIZE (KiB * 128 * 256) >> #define RPMB_KEY_MAC_SIZE 32 >> +#define RPMB_BLOCK_SIZE 256 >> >> /* RPMB Request Types */ >> #define VIRTIO_RPMB_REQ_PROGRAM_KEY 0x0001 >> @@ -100,7 +101,7 @@ struct virtio_rpmb_config { >> struct virtio_rpmb_frame { >> uint8_t stuff[196]; >> uint8_t key_mac[RPMB_KEY_MAC_SIZE]; >> - uint8_t data[256]; >> + uint8_t data[RPMB_BLOCK_SIZE]; >> uint8_t nonce[16]; >> /* remaining fields are big-endian */ >> uint32_t write_counter; >> @@ -124,6 +125,7 @@ typedef struct VuRpmb { >> uint8_t last_nonce[16]; >> uint16_t last_result; >> uint16_t last_reqresp; >> + uint16_t last_address; >> uint32_t write_count; >> } VuRpmb; >> >> @@ -239,17 +241,30 @@ vrpmb_set_config(VuDev *dev, const uint8_t *data, >> * which itself uses a 3 clause BSD chunk of code. >> */ >> >> +static const int rpmb_frame_dlen = (sizeof(struct virtio_rpmb_frame) - >> + offsetof(struct virtio_rpmb_frame, data)); >> + >> static void vrpmb_update_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) >> { >> hmac_sha256_ctx ctx; >> - static const int dlen = (sizeof(struct virtio_rpmb_frame) - >> - offsetof(struct virtio_rpmb_frame, data)); >> >> hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); >> - hmac_sha256_update(&ctx, frm->data, dlen); >> + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); >> hmac_sha256_final(&ctx, &frm->key_mac[0], 32); >> } >> >> +static bool vrpmb_verify_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) >> +{ >> + hmac_sha256_ctx ctx; >> + uint8_t calculated_mac[RPMB_KEY_MAC_SIZE]; >> + >> + hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); >> + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); >> + hmac_sha256_final(&ctx, calculated_mac, RPMB_KEY_MAC_SIZE); >> + >> + return memcmp(calculated_mac, frm->key_mac, RPMB_KEY_MAC_SIZE) == 0; >> > I'd prefer using a constant time comparison function for this one > instead of memcmp (regardless if it's used for simulation or not) to > prevent eventual timing attacks. Could you recommend such a function for this? > >> +} >> + >> /* >> * Handlers for individual control messages >> */ >> @@ -324,6 +339,82 @@ vrpmb_handle_get_write_counter(VuDev *dev, struct virtio_rpmb_frame *frame) >> return resp; >> } >> >> +/* >> + * vrpmb_handle_write: >> + * >> + * We will report the success/fail on receipt of >> + * VIRTIO_RPMB_REQ_RESULT_READ. Returns the number of extra frames >> + * processed in the request. >> + */ >> +static int vrpmb_handle_write(VuDev *dev, struct virtio_rpmb_frame *frame) >> +{ >> + VuRpmb *r = container_of(dev, VuRpmb, dev.parent); >> + int extra_frames = 0; >> + uint16_t block_count = be16toh(frame->block_count); >> + uint32_t write_counter = be32toh(frame->write_counter); >> + size_t offset; >> + >> + r->last_reqresp = VIRTIO_RPMB_RESP_DATA_WRITE; >> + r->last_address = be16toh(frame->address); >> + offset = r->last_address * RPMB_BLOCK_SIZE; >> + >> + /* >> + * Run the checks from: >> + * 5.12.6.1.3 Device Requirements: Device Operation: Data Write >> + */ >> + if (!r->key) { >> + g_warning("no key programmed"); >> + r->last_result = VIRTIO_RPMB_RES_NO_AUTH_KEY; >> + } else if (block_count == 0 || >> + block_count > r->virtio_config.max_wr_cnt) { >> + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; >> + } else if (false /* what does an expired write counter mean? */) { >> > IIRC, the counter has room for a 32-bit value and the counter will never > wrap around. So once the counter have reached max for uint32_t, then > there is an additional bit set (permanently) in the operation result. > I.e., writes are no longer possible once that has happened. That is > probably what you're referring to here I suppose. That would make sense. I'll see if I can make the spec language a bit clearer as well. > >> + r->last_result = VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED; >> + } else if (offset > (r->virtio_config.capacity * (128 * KiB))) { >> + r->last_result = VIRTIO_RPMB_RES_ADDR_FAILURE; >> + } else if (!vrpmb_verify_mac_in_frame(r, frame)) { >> + r->last_result = VIRTIO_RPMB_RES_AUTH_FAILURE; >> + } else if (write_counter != r->write_count) { >> + r->last_result = VIRTIO_RPMB_RES_COUNT_FAILURE; >> + } else { >> + int i; >> + /* At this point we have a valid authenticated write request >> + * so the counter can incremented and we can attempt to >> + * update the backing device. >> + */ >> + r->write_count++; >> + for (i = 0; i < block_count; i++) { >> + void *blk = r->flash_map + offset; >> + g_debug("%s: writing block %d", __func__, i); >> + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_WRITE) != 0) { >> + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; >> + break; >> + } >> + memcpy(blk, frame[i].data, RPMB_BLOCK_SIZE); >> + if (msync(blk, RPMB_BLOCK_SIZE, MS_SYNC) != 0) { >> + g_warning("%s: failed to sync update", __func__); >> + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; >> + break; >> + } >> + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_READ) != 0) { >> + g_warning("%s: failed to re-apply read protection", __func__); >> + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; >> + break; >> + } >> + offset += RPMB_BLOCK_SIZE; >> + } >> + r->last_result = VIRTIO_RPMB_RES_OK; >> + extra_frames = i - 1; >> + } >> + >> + g_info("%s: %s (%x, %d extra frames processed), write_count=%d", __func__, >> + r->last_result == VIRTIO_RPMB_RES_OK ? "successful":"failed", >> + r->last_result, extra_frames, r->write_count); >> + >> + return extra_frames; >> +} >> + >> + >> /* >> * Return the result of the last message. This is only valid if the >> * previous message was VIRTIO_RPMB_REQ_PROGRAM_KEY or >> @@ -339,10 +430,14 @@ static struct virtio_rpmb_frame * vrpmb_handle_result_read(VuDev *dev) >> g_info("%s: for request:%x result:%x", __func__, >> r->last_reqresp, r->last_result); >> >> - if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY || >> - r->last_reqresp == VIRTIO_RPMB_REQ_DATA_WRITE) { >> + if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY) { >> resp->result = htobe16(r->last_result); >> resp->req_resp = htobe16(r->last_reqresp); >> + } else if (r->last_reqresp == VIRTIO_RPMB_RESP_DATA_WRITE) { >> + resp->result = htobe16(r->last_result); >> + resp->req_resp = htobe16(r->last_reqresp); >> + resp->write_counter = htobe32(r->write_count); >> + resp->address = htobe16(r->last_address); >> } else { >> resp->result = htobe16(VIRTIO_RPMB_RES_GENERAL_FAILURE); >> } >> @@ -445,6 +540,10 @@ vrpmb_handle_ctrl(VuDev *dev, int qidx) >> __func__); >> } >> break; >> + case VIRTIO_RPMB_REQ_DATA_WRITE: >> + /* we can have multiple blocks handled */ >> + n += vrpmb_handle_write(dev, f); >> + break; >> default: >> g_debug("un-handled request: %x", f->req_resp); >> break; >> -- >> 2.20.1 >> Thanks!
On Mon, Sep 28, 2020 at 03:56:19PM +0100, Alex Bennée wrote: > > Joakim Bech <joakim.bech@linaro.org> writes: > > > On Fri, Sep 25, 2020 at 01:51:43PM +0100, Alex Bennée wrote: > >> With this command we are finally updating data to the backing store > >> and cycling the write_count and each successful write. We also include > >> the write count in all response frames as the spec is a little unclear > >> but the example test code expected it. > >> > >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > >> --- > >> tools/vhost-user-rpmb/main.c | 111 +++++++++++++++++++++++++++++++++-- > >> 1 file changed, 105 insertions(+), 6 deletions(-) > >> > >> diff --git a/tools/vhost-user-rpmb/main.c b/tools/vhost-user-rpmb/main.c > >> index 88747c50fa44..a17c3b4bcc4e 100644 > >> --- a/tools/vhost-user-rpmb/main.c > >> +++ b/tools/vhost-user-rpmb/main.c > >> @@ -62,6 +62,7 @@ enum { > >> #define KiB (1UL << 10) > >> #define MAX_RPMB_SIZE (KiB * 128 * 256) > >> #define RPMB_KEY_MAC_SIZE 32 > >> +#define RPMB_BLOCK_SIZE 256 > >> > >> /* RPMB Request Types */ > >> #define VIRTIO_RPMB_REQ_PROGRAM_KEY 0x0001 > >> @@ -100,7 +101,7 @@ struct virtio_rpmb_config { > >> struct virtio_rpmb_frame { > >> uint8_t stuff[196]; > >> uint8_t key_mac[RPMB_KEY_MAC_SIZE]; > >> - uint8_t data[256]; > >> + uint8_t data[RPMB_BLOCK_SIZE]; > >> uint8_t nonce[16]; > >> /* remaining fields are big-endian */ > >> uint32_t write_counter; > >> @@ -124,6 +125,7 @@ typedef struct VuRpmb { > >> uint8_t last_nonce[16]; > >> uint16_t last_result; > >> uint16_t last_reqresp; > >> + uint16_t last_address; > >> uint32_t write_count; > >> } VuRpmb; > >> > >> @@ -239,17 +241,30 @@ vrpmb_set_config(VuDev *dev, const uint8_t *data, > >> * which itself uses a 3 clause BSD chunk of code. > >> */ > >> > >> +static const int rpmb_frame_dlen = (sizeof(struct virtio_rpmb_frame) - > >> + offsetof(struct virtio_rpmb_frame, data)); > >> + > >> static void vrpmb_update_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) > >> { > >> hmac_sha256_ctx ctx; > >> - static const int dlen = (sizeof(struct virtio_rpmb_frame) - > >> - offsetof(struct virtio_rpmb_frame, data)); > >> > >> hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); > >> - hmac_sha256_update(&ctx, frm->data, dlen); > >> + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); > >> hmac_sha256_final(&ctx, &frm->key_mac[0], 32); > >> } > >> > >> +static bool vrpmb_verify_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) > >> +{ > >> + hmac_sha256_ctx ctx; > >> + uint8_t calculated_mac[RPMB_KEY_MAC_SIZE]; > >> + > >> + hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); > >> + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); > >> + hmac_sha256_final(&ctx, calculated_mac, RPMB_KEY_MAC_SIZE); > >> + > >> + return memcmp(calculated_mac, frm->key_mac, RPMB_KEY_MAC_SIZE) == 0; > >> > > I'd prefer using a constant time comparison function for this one > > instead of memcmp (regardless if it's used for simulation or not) to > > prevent eventual timing attacks. > > Could you recommend such a function for this? > Here is such an implementation: https://github.com/OP-TEE/optee_os/blob/master/lib/libutils/ext/consttime_memcmp.c However, cross check the license so it's OK to use. If not there are similar implementations out there under other licenses. > > > >> +} > >> + > >> /* > >> * Handlers for individual control messages > >> */ > >> @@ -324,6 +339,82 @@ vrpmb_handle_get_write_counter(VuDev *dev, struct virtio_rpmb_frame *frame) > >> return resp; > >> } > >> > >> +/* > >> + * vrpmb_handle_write: > >> + * > >> + * We will report the success/fail on receipt of > >> + * VIRTIO_RPMB_REQ_RESULT_READ. Returns the number of extra frames > >> + * processed in the request. > >> + */ > >> +static int vrpmb_handle_write(VuDev *dev, struct virtio_rpmb_frame *frame) > >> +{ > >> + VuRpmb *r = container_of(dev, VuRpmb, dev.parent); > >> + int extra_frames = 0; > >> + uint16_t block_count = be16toh(frame->block_count); > >> + uint32_t write_counter = be32toh(frame->write_counter); > >> + size_t offset; > >> + > >> + r->last_reqresp = VIRTIO_RPMB_RESP_DATA_WRITE; > >> + r->last_address = be16toh(frame->address); > >> + offset = r->last_address * RPMB_BLOCK_SIZE; > >> + > >> + /* > >> + * Run the checks from: > >> + * 5.12.6.1.3 Device Requirements: Device Operation: Data Write > >> + */ > >> + if (!r->key) { > >> + g_warning("no key programmed"); > >> + r->last_result = VIRTIO_RPMB_RES_NO_AUTH_KEY; > >> + } else if (block_count == 0 || > >> + block_count > r->virtio_config.max_wr_cnt) { > >> + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; > >> + } else if (false /* what does an expired write counter mean? */) { > >> > > IIRC, the counter has room for a 32-bit value and the counter will never > > wrap around. So once the counter have reached max for uint32_t, then > > there is an additional bit set (permanently) in the operation result. > > I.e., writes are no longer possible once that has happened. That is > > probably what you're referring to here I suppose. > > That would make sense. I'll see if I can make the spec language a bit > clearer as well. > > > > >> + r->last_result = VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED; > >> + } else if (offset > (r->virtio_config.capacity * (128 * KiB))) { > >> + r->last_result = VIRTIO_RPMB_RES_ADDR_FAILURE; > >> + } else if (!vrpmb_verify_mac_in_frame(r, frame)) { > >> + r->last_result = VIRTIO_RPMB_RES_AUTH_FAILURE; > >> + } else if (write_counter != r->write_count) { > >> + r->last_result = VIRTIO_RPMB_RES_COUNT_FAILURE; > >> + } else { > >> + int i; > >> + /* At this point we have a valid authenticated write request > >> + * so the counter can incremented and we can attempt to > >> + * update the backing device. > >> + */ > >> + r->write_count++; > >> + for (i = 0; i < block_count; i++) { > >> + void *blk = r->flash_map + offset; > >> + g_debug("%s: writing block %d", __func__, i); > >> + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_WRITE) != 0) { > >> + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; > >> + break; > >> + } > >> + memcpy(blk, frame[i].data, RPMB_BLOCK_SIZE); > >> + if (msync(blk, RPMB_BLOCK_SIZE, MS_SYNC) != 0) { > >> + g_warning("%s: failed to sync update", __func__); > >> + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; > >> + break; > >> + } > >> + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_READ) != 0) { > >> + g_warning("%s: failed to re-apply read protection", __func__); > >> + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; > >> + break; > >> + } > >> + offset += RPMB_BLOCK_SIZE; > >> + } > >> + r->last_result = VIRTIO_RPMB_RES_OK; > >> + extra_frames = i - 1; > >> + } > >> + > >> + g_info("%s: %s (%x, %d extra frames processed), write_count=%d", __func__, > >> + r->last_result == VIRTIO_RPMB_RES_OK ? "successful":"failed", > >> + r->last_result, extra_frames, r->write_count); > >> + > >> + return extra_frames; > >> +} > >> + > >> + > >> /* > >> * Return the result of the last message. This is only valid if the > >> * previous message was VIRTIO_RPMB_REQ_PROGRAM_KEY or > >> @@ -339,10 +430,14 @@ static struct virtio_rpmb_frame * vrpmb_handle_result_read(VuDev *dev) > >> g_info("%s: for request:%x result:%x", __func__, > >> r->last_reqresp, r->last_result); > >> > >> - if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY || > >> - r->last_reqresp == VIRTIO_RPMB_REQ_DATA_WRITE) { > >> + if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY) { > >> resp->result = htobe16(r->last_result); > >> resp->req_resp = htobe16(r->last_reqresp); > >> + } else if (r->last_reqresp == VIRTIO_RPMB_RESP_DATA_WRITE) { > >> + resp->result = htobe16(r->last_result); > >> + resp->req_resp = htobe16(r->last_reqresp); > >> + resp->write_counter = htobe32(r->write_count); > >> + resp->address = htobe16(r->last_address); > >> } else { > >> resp->result = htobe16(VIRTIO_RPMB_RES_GENERAL_FAILURE); > >> } > >> @@ -445,6 +540,10 @@ vrpmb_handle_ctrl(VuDev *dev, int qidx) > >> __func__); > >> } > >> break; > >> + case VIRTIO_RPMB_REQ_DATA_WRITE: > >> + /* we can have multiple blocks handled */ > >> + n += vrpmb_handle_write(dev, f); > >> + break; > >> default: > >> g_debug("un-handled request: %x", f->req_resp); > >> break; > >> -- > >> 2.20.1 > >> > > Thanks! > > -- > Alex Bennée
diff --git a/tools/vhost-user-rpmb/main.c b/tools/vhost-user-rpmb/main.c index 88747c50fa44..a17c3b4bcc4e 100644 --- a/tools/vhost-user-rpmb/main.c +++ b/tools/vhost-user-rpmb/main.c @@ -62,6 +62,7 @@ enum { #define KiB (1UL << 10) #define MAX_RPMB_SIZE (KiB * 128 * 256) #define RPMB_KEY_MAC_SIZE 32 +#define RPMB_BLOCK_SIZE 256 /* RPMB Request Types */ #define VIRTIO_RPMB_REQ_PROGRAM_KEY 0x0001 @@ -100,7 +101,7 @@ struct virtio_rpmb_config { struct virtio_rpmb_frame { uint8_t stuff[196]; uint8_t key_mac[RPMB_KEY_MAC_SIZE]; - uint8_t data[256]; + uint8_t data[RPMB_BLOCK_SIZE]; uint8_t nonce[16]; /* remaining fields are big-endian */ uint32_t write_counter; @@ -124,6 +125,7 @@ typedef struct VuRpmb { uint8_t last_nonce[16]; uint16_t last_result; uint16_t last_reqresp; + uint16_t last_address; uint32_t write_count; } VuRpmb; @@ -239,17 +241,30 @@ vrpmb_set_config(VuDev *dev, const uint8_t *data, * which itself uses a 3 clause BSD chunk of code. */ +static const int rpmb_frame_dlen = (sizeof(struct virtio_rpmb_frame) - + offsetof(struct virtio_rpmb_frame, data)); + static void vrpmb_update_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) { hmac_sha256_ctx ctx; - static const int dlen = (sizeof(struct virtio_rpmb_frame) - - offsetof(struct virtio_rpmb_frame, data)); hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); - hmac_sha256_update(&ctx, frm->data, dlen); + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); hmac_sha256_final(&ctx, &frm->key_mac[0], 32); } +static bool vrpmb_verify_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm) +{ + hmac_sha256_ctx ctx; + uint8_t calculated_mac[RPMB_KEY_MAC_SIZE]; + + hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE); + hmac_sha256_update(&ctx, frm->data, rpmb_frame_dlen); + hmac_sha256_final(&ctx, calculated_mac, RPMB_KEY_MAC_SIZE); + + return memcmp(calculated_mac, frm->key_mac, RPMB_KEY_MAC_SIZE) == 0; +} + /* * Handlers for individual control messages */ @@ -324,6 +339,82 @@ vrpmb_handle_get_write_counter(VuDev *dev, struct virtio_rpmb_frame *frame) return resp; } +/* + * vrpmb_handle_write: + * + * We will report the success/fail on receipt of + * VIRTIO_RPMB_REQ_RESULT_READ. Returns the number of extra frames + * processed in the request. + */ +static int vrpmb_handle_write(VuDev *dev, struct virtio_rpmb_frame *frame) +{ + VuRpmb *r = container_of(dev, VuRpmb, dev.parent); + int extra_frames = 0; + uint16_t block_count = be16toh(frame->block_count); + uint32_t write_counter = be32toh(frame->write_counter); + size_t offset; + + r->last_reqresp = VIRTIO_RPMB_RESP_DATA_WRITE; + r->last_address = be16toh(frame->address); + offset = r->last_address * RPMB_BLOCK_SIZE; + + /* + * Run the checks from: + * 5.12.6.1.3 Device Requirements: Device Operation: Data Write + */ + if (!r->key) { + g_warning("no key programmed"); + r->last_result = VIRTIO_RPMB_RES_NO_AUTH_KEY; + } else if (block_count == 0 || + block_count > r->virtio_config.max_wr_cnt) { + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; + } else if (false /* what does an expired write counter mean? */) { + r->last_result = VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED; + } else if (offset > (r->virtio_config.capacity * (128 * KiB))) { + r->last_result = VIRTIO_RPMB_RES_ADDR_FAILURE; + } else if (!vrpmb_verify_mac_in_frame(r, frame)) { + r->last_result = VIRTIO_RPMB_RES_AUTH_FAILURE; + } else if (write_counter != r->write_count) { + r->last_result = VIRTIO_RPMB_RES_COUNT_FAILURE; + } else { + int i; + /* At this point we have a valid authenticated write request + * so the counter can incremented and we can attempt to + * update the backing device. + */ + r->write_count++; + for (i = 0; i < block_count; i++) { + void *blk = r->flash_map + offset; + g_debug("%s: writing block %d", __func__, i); + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_WRITE) != 0) { + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; + break; + } + memcpy(blk, frame[i].data, RPMB_BLOCK_SIZE); + if (msync(blk, RPMB_BLOCK_SIZE, MS_SYNC) != 0) { + g_warning("%s: failed to sync update", __func__); + r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE; + break; + } + if (mprotect(blk, RPMB_BLOCK_SIZE, PROT_READ) != 0) { + g_warning("%s: failed to re-apply read protection", __func__); + r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE; + break; + } + offset += RPMB_BLOCK_SIZE; + } + r->last_result = VIRTIO_RPMB_RES_OK; + extra_frames = i - 1; + } + + g_info("%s: %s (%x, %d extra frames processed), write_count=%d", __func__, + r->last_result == VIRTIO_RPMB_RES_OK ? "successful":"failed", + r->last_result, extra_frames, r->write_count); + + return extra_frames; +} + + /* * Return the result of the last message. This is only valid if the * previous message was VIRTIO_RPMB_REQ_PROGRAM_KEY or @@ -339,10 +430,14 @@ static struct virtio_rpmb_frame * vrpmb_handle_result_read(VuDev *dev) g_info("%s: for request:%x result:%x", __func__, r->last_reqresp, r->last_result); - if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY || - r->last_reqresp == VIRTIO_RPMB_REQ_DATA_WRITE) { + if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY) { resp->result = htobe16(r->last_result); resp->req_resp = htobe16(r->last_reqresp); + } else if (r->last_reqresp == VIRTIO_RPMB_RESP_DATA_WRITE) { + resp->result = htobe16(r->last_result); + resp->req_resp = htobe16(r->last_reqresp); + resp->write_counter = htobe32(r->write_count); + resp->address = htobe16(r->last_address); } else { resp->result = htobe16(VIRTIO_RPMB_RES_GENERAL_FAILURE); } @@ -445,6 +540,10 @@ vrpmb_handle_ctrl(VuDev *dev, int qidx) __func__); } break; + case VIRTIO_RPMB_REQ_DATA_WRITE: + /* we can have multiple blocks handled */ + n += vrpmb_handle_write(dev, f); + break; default: g_debug("un-handled request: %x", f->req_resp); break;
With this command we are finally updating data to the backing store and cycling the write_count and each successful write. We also include the write count in all response frames as the spec is a little unclear but the example test code expected it. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- tools/vhost-user-rpmb/main.c | 111 +++++++++++++++++++++++++++++++++-- 1 file changed, 105 insertions(+), 6 deletions(-)