refactor credmgmt

This patch fixes the following issues to make Google Chrome happy:
1. Adds CTAP_CBOR_CRED_MGMT(0x0A) which is an alias to CTAP_CBOR_CRED_MGMT_PRE(0x41)
2. Returns success instead of NO_CREDENTIALS when there are no RKs
3. Skip the "icon" property if it's empty

Tested with Google Chrome Version 80.0.3987.149

README.md

@@ -61,9 +61,11 @@ git checkout ${VERSION_TO_BUILD}
 git submodule update --init --recursive
 ```
 
-## Installing the toolchain
+## Installing the toolchain and applying updates
 
-In order to compile ARM code, you need the ARM compiler and other things like bundling bootloader and firmware require the `solo-python` python package. Check our [documentation](https://docs.solokeys.io/solo/) for details
+In order to compile ARM code, you need the ARM compiler and other things like bundling bootloader and firmware require the [solo-python](https://github.com/solokeys/solo-python) python package. Check our [documentation](https://docs.solokeys.io/solo/) for details.
+
+You can update your solokey after running `pip3 install solo-python` with `solo key update` for the latest version. To apply a custom image use `solo program bootloader <file>(.json|.hex)`.
 
 ## Installing the toolkit and compiling in Docker 
 Alternatively, you can use Docker to create a container with the toolchain.

STABLE_VERSION

@@ -1 +1 @@
-3.1.1
+3.2.0

docs/solo/building.md

@@ -104,9 +104,24 @@ solo mergehex bootloader.hex solo.hex bundle.hex
 
 `bundle.hex` is our complete firmware build.  Note it is in this step that you can
 include a custom attestation certificate or lock the device from debugging/DFU.
-By default the "hacker" attestation certifcate and key is used.
+By default the "hacker" attestation certifcate and key is used.  Use the `--lock` flag
+to make this permanent.
 
 ```
+solo mergehex  \
+    --attestation-key "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" \
+    --attestation-cert attestation.der \
+    solo.hex \
+    bootloader.hex \
+    bundle.hex
+```
+
+**Warning**: If you use `--lock`, this will permanently lock the device to this new bootloader.  You
+won't be able to program the bootloader again or be able to connect a hardware debugger.
+The new bootloader may be able to accept (signed) updates still, depending on how you configured it.
+
+```
+# Permanent!
 solo mergehex  \
     --attestation-key "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" \
     --attestation-cert attestation.der \
@@ -118,9 +133,5 @@ solo mergehex  \
 
 See [here for more information on custom attestation](/solo/customization/).
 
-If you use `--lock`, this will permanently lock the device to this new bootloader.  You
-won't be able to program the bootloader again or be able to connect a hardware debugger.
-The new bootloader may be able to accept (signed) updates still, depending on how you configured it.
-
 To learn more about normal updates or a "full" update, you should [read more on Solo's boot stages](/solo/bootloader-mode).
 

docs/solo/customization.md

@@ -74,7 +74,7 @@ Note you must use a prime256v1 curve for this step, and you must leave the unit/
 country=US
 state=Maine
 organization=OpenSourceSecurity
-unit="Authenticator Attestation"
+unit="Authenticator Attestation"    # MUST KEEP THIS AS "Authenticator Attestation" for FIDO2.
 CN=example.com
 email=example@example.com
 
@@ -134,6 +134,8 @@ solo mergehex  \
     bundle.hex
 ```
 
+**Warning**: Using the `--lock` flag prevents the DFU from being accessed on the device again.  It's recommended to try first without the `--lock` flag to make sure it works.
+
 Now you have a newly created `bundle.hex` file with a custom attestation key and cert.  You can [program this `bundle.hex` file
 with Solo in DFU mode](/solo/programming#procedure).
 

fido2/ctap.h

@@ -16,7 +16,9 @@
 #define CTAP_CLIENT_PIN             0x06
 #define CTAP_RESET                  0x07
 #define GET_NEXT_ASSERTION          0x08
+#define CTAP_CBOR_CRED_MGMT         0x0A
 #define CTAP_VENDOR_FIRST           0x40
+#define CTAP_CBOR_CRED_MGMT_PRE     0x41
 #define CTAP_VENDOR_LAST            0xBF
 
 #define MC_clientDataHash         0x01
@@ -37,6 +39,19 @@
 #define GA_pinAuth                0x06
 #define GA_pinProtocol            0x07
 
+#define CM_cmd                    0x01
+    #define CM_cmdMetadata        0x01
+    #define CM_cmdRPBegin         0x02
+    #define CM_cmdRPNext          0x03
+    #define CM_cmdRKBegin         0x04
+    #define CM_cmdRKNext          0x05
+    #define CM_cmdRKDelete        0x06
+#define CM_subCommandParams       0x02
+    #define CM_subCommandRpId     0x01
+    #define CM_subCommandCred     0x02
+#define CM_pinProtocol            0x03
+#define CM_pinAuth                0x04
+
 #define CP_pinProtocol            0x01
 #define CP_subCommand             0x02
     #define CP_cmdGetRetries      0x01
@@ -58,6 +73,11 @@
 #define EXT_HMAC_SECRET_REQUESTED   0x01
 #define EXT_HMAC_SECRET_PARSED      0x02
 
+#define EXT_CRED_PROTECT_INVALID                0x00
+#define EXT_CRED_PROTECT_OPTIONAL               0x01
+#define EXT_CRED_PROTECT_OPTIONAL_WITH_CREDID   0x02
+#define EXT_CRED_PROTECT_REQUIRED               0x03
+
 #define RESP_versions               0x1
 #define RESP_extensions             0x2
 #define RESP_aaguid                 0x3
@@ -141,16 +161,29 @@ typedef struct
 
 typedef struct {
     uint8_t tag[CREDENTIAL_TAG_SIZE];
+    union {
         uint8_t nonce[CREDENTIAL_NONCE_SIZE];
+        struct {
+            uint8_t _pad[CREDENTIAL_NONCE_SIZE - 4];
+            uint32_t value;
+        }__attribute__((packed)) metadata;
+    }__attribute__((packed)) entropy;
     uint8_t rpIdHash[32];
     uint32_t count;
 }__attribute__((packed)) CredentialId;
 
-struct Credential {
+struct  __attribute__((packed)) Credential {
     CredentialId id;
     CTAP_userEntity user;
 };
-typedef struct Credential CTAP_residentKey;
+typedef struct {
+    CredentialId id;
+    CTAP_userEntity user;
+
+    // Maximum amount of "extra" space in resident key.
+    uint8_t rpId[48];
+    uint8_t rpIdSize;
+} __attribute__((packed)) CTAP_residentKey;
 
 typedef struct
 {
@@ -217,6 +250,7 @@ typedef struct
 {
     uint8_t hmac_secret_present;
     CTAP_hmac_secret hmac_secret;
+    uint32_t cred_protect;
 } CTAP_extensions;
 
 typedef struct
@@ -285,6 +319,26 @@ typedef struct
 
 } CTAP_getAssertion;
 
+typedef struct
+{
+    int cmd;
+    struct {
+        uint8_t rpIdHash[32];
+        CTAP_credentialDescriptor credentialDescriptor;
+    } subCommandParams;
+
+    struct {
+        uint8_t cmd;
+        uint8_t subCommandParamsCborCopy[sizeof(CTAP_credentialDescriptor) + 16];
+    } hashed;
+    uint32_t subCommandParamsCborSize;
+
+    uint8_t pinAuth[16];
+    uint8_t pinAuthPresent;
+    int pinProtocol;
+} CTAP_credMgmt;
+
+
 typedef struct
 {
     int pinProtocol;
@@ -303,7 +357,12 @@ typedef struct
 
 
 struct _getAssertionState {
+    // Room for both authData struct and extensions
+    struct {
         CTAP_authDataHeader authData;
+        uint8_t extensions[80];
+    } __attribute__((packed)) buf;
+    CTAP_extensions extensions;
     uint8_t clientDataHash[CLIENT_DATA_HASH_SIZE];
     CTAP_credentialDescriptor creds[ALLOW_LIST_MAX_SIZE];
     uint8_t lastcmd;

fido2/ctap_parse.c

@@ -698,6 +698,14 @@ uint8_t ctap_parse_extensions(CborValue * val, CTAP_extensions * ext)
                 printf1(TAG_RED, "warning: hmac_secret request ignored for being wrong type\r\n");
             }
         }
+        else if (strncmp(key, "credProtect",11) == 0) {
+            if (cbor_value_get_type(&map) == CborIntegerType) {
+                ret = cbor_value_get_int(&map, (int*)&ext->cred_protect);
+                check_ret(ret);
+            } else {
+                printf1(TAG_RED, "warning: credProtect request ignored for being wrong type\r\n");
+            }
+        }
 
         ret = cbor_value_advance(&map);
         check_ret(ret);
@@ -871,7 +879,7 @@ uint8_t ctap_parse_make_credential(CTAP_makeCredential * MC, CborEncoder * encod
         {
             return ret;
         }
-        cbor_value_advance(&map);
+        ret = cbor_value_advance(&map);
         check_ret(ret);
     }
 
@@ -999,6 +1007,163 @@ uint8_t parse_allow_list(CTAP_getAssertion * GA, CborValue * it)
     return 0;
 }
 
+static uint8_t parse_cred_mgmt_subcommandparams(CborValue * val, CTAP_credMgmt * CM)
+{
+    size_t map_length;
+    int key;
+    int ret;
+    unsigned int i;
+    CborValue map;
+    size_t sz = 32;
+
+    if (cbor_value_get_type(val) != CborMapType)
+    {
+        printf2(TAG_ERR,"error, wrong type\n");
+        return CTAP2_ERR_INVALID_CBOR_TYPE;
+    }
+
+
+    ret = cbor_value_enter_container(val,&map);
+    check_ret(ret);
+    
+    const uint8_t * start_byte = cbor_value_get_next_byte(&map) - 1;
+
+    ret = cbor_value_get_map_length(val, &map_length);
+    check_ret(ret);
+
+    for (i = 0; i < map_length; i++)
+    {
+        if (cbor_value_get_type(&map) != CborIntegerType)
+        {
+            printf2(TAG_ERR,"Error, expecting integer type for map key, got %s\n", cbor_value_get_type_string(&map));
+            return CTAP2_ERR_INVALID_CBOR_TYPE;
+        }
+        ret = cbor_value_get_int(&map, &key);
+        check_ret(ret);
+        ret = cbor_value_advance(&map);
+        check_ret(ret);
+        switch(key)
+        {
+            case CM_subCommandRpId:
+                ret = cbor_value_copy_byte_string(&map, CM->subCommandParams.rpIdHash, &sz, NULL);
+                if (ret == CborErrorOutOfMemory)
+                {
+                    printf2(TAG_ERR,"Error, map key is too large\n");
+                    return CTAP2_ERR_LIMIT_EXCEEDED;
+                }
+                check_ret(ret);
+                break;
+            case CM_subCommandCred:
+                ret = parse_credential_descriptor(&map, &CM->subCommandParams.credentialDescriptor);
+                check_ret(ret);;
+                break;
+        }
+        ret = cbor_value_advance(&map);
+        check_ret(ret);
+    }
+
+    const uint8_t * end_byte = cbor_value_get_next_byte(&map);
+
+    uint32_t length = (uint32_t)end_byte - (uint32_t)start_byte;
+    if (length > sizeof(CM->hashed.subCommandParamsCborCopy))
+    {
+        return CTAP2_ERR_LIMIT_EXCEEDED;
+    }
+    // Copy the details that were hashed so they can be verified later.
+    memmove(CM->hashed.subCommandParamsCborCopy, start_byte, length);
+    CM->subCommandParamsCborSize = length;
+
+    return 0;
+}
+
+uint8_t ctap_parse_cred_mgmt(CTAP_credMgmt * CM, uint8_t * request, int length)
+{
+    int ret;
+    unsigned int i;
+    int key;
+    size_t map_length;
+    CborParser parser;
+    CborValue it,map;
+
+    memset(CM, 0, sizeof(CTAP_credMgmt));
+    ret = cbor_parser_init(request, length, CborValidateCanonicalFormat, &parser, &it);
+    check_ret(ret);
+
+    CborType type = cbor_value_get_type(&it);
+    if (type != CborMapType)
+    {
+        printf2(TAG_ERR,"Error, expecting cbor map\n");
+        return CTAP2_ERR_INVALID_CBOR_TYPE;
+    }
+
+
+    ret = cbor_value_enter_container(&it,&map);
+    check_ret(ret);
+
+    ret = cbor_value_get_map_length(&it, &map_length);
+    check_ret(ret);
+
+    printf1(TAG_PARSE, "CM map has %d elements\n", map_length);
+
+    for (i = 0; i < map_length; i++)
+    {
+        type = cbor_value_get_type(&map);
+        if (type != CborIntegerType)
+        {
+            printf2(TAG_ERR,"Error, expecting int for map key\n");
+            return CTAP2_ERR_INVALID_CBOR_TYPE;
+        }
+        ret = cbor_value_get_int_checked(&map, &key);
+        check_ret(ret);
+
+        ret = cbor_value_advance(&map);
+        check_ret(ret);
+
+        switch(key)
+        {
+            case CM_cmd:
+                printf1(TAG_PARSE, "CM_cmd\n");
+                if (cbor_value_get_type(&map) == CborIntegerType)
+                {
+                    ret = cbor_value_get_int_checked(&map, &CM->cmd);
+                    check_ret(ret);
+                    CM->hashed.cmd = CM->cmd;
+                }
+                else
+                {
+                    return CTAP2_ERR_INVALID_CBOR_TYPE;
+                }
+                break;
+            case CM_subCommandParams:
+                printf1(TAG_PARSE, "CM_subCommandParams\n");
+                ret = parse_cred_mgmt_subcommandparams(&map, CM);
+                check_ret(ret);
+                break;
+            case CM_pinProtocol:
+                printf1(TAG_PARSE, "CM_pinProtocol\n");
+                if (cbor_value_get_type(&map) == CborIntegerType)
+                {
+                    ret = cbor_value_get_int_checked(&map, &CM->pinProtocol);
+                    check_ret(ret);
+                }
+                else
+                {
+                    return CTAP2_ERR_INVALID_CBOR_TYPE;
+                }
+                break;
+            case CM_pinAuth:
+                printf1(TAG_PARSE, "CM_pinAuth\n");
+                ret = parse_fixed_byte_string(&map, CM->pinAuth, 16);
+                check_retr(ret);
+                CM->pinAuthPresent = 1;
+                break;
+        }
+        ret = cbor_value_advance(&map);
+        check_ret(ret);
+    }
+
+    return 0;
+}
 
 uint8_t ctap_parse_get_assertion(CTAP_getAssertion * GA, uint8_t * request, int length)
 {
@@ -1132,7 +1297,7 @@ uint8_t ctap_parse_get_assertion(CTAP_getAssertion * GA, uint8_t * request, int
             return ret;
         }
 
-        cbor_value_advance(&map);
+        ret = cbor_value_advance(&map);
         check_ret(ret);
     }
 

fido2/ctap_parse.h

@@ -35,6 +35,7 @@ uint8_t parse_cose_key(CborValue * it, COSE_key * cose);
 
 uint8_t ctap_parse_make_credential(CTAP_makeCredential * MC, CborEncoder * encoder, uint8_t * request, int length);
 uint8_t ctap_parse_get_assertion(CTAP_getAssertion * GA, uint8_t * request, int length);
+uint8_t ctap_parse_cred_mgmt(CTAP_credMgmt * CM, uint8_t * request, int length);
 uint8_t ctap_parse_client_pin(CTAP_clientPin * CP, uint8_t * request, int length);
 uint8_t parse_credential_descriptor(CborValue * arr, CTAP_credentialDescriptor * cred);
 

fido2/ctaphid.c

@@ -734,6 +734,11 @@ uint8_t ctaphid_custom_command(int len, CTAP_RESPONSE * ctap_resp, CTAPHID_WRITE
             ctaphid_write(wb, NULL, 0);
             return 1;
 #endif
+#if defined(SOLO)
+        case CTAPHID_REBOOT:
+            device_reboot();
+            return 1;
+#endif
 
 #if !defined(IS_BOOTLOADER)
         case CTAPHID_GETRNG:
@@ -779,30 +784,37 @@ uint8_t ctaphid_custom_command(int len, CTAP_RESPONSE * ctap_resp, CTAPHID_WRITE
         case CTAPHID_LOADKEY:
             /**
              * Load external key.  Useful for enabling backups.
-             * bytes:            4                   96
-             * payload: | counter_increase (BE) | master_key |
+             * bytes:                   4                     4                      96
+             * payload:  version [maj rev patch RFU]| counter_replacement (BE) | master_key |
              * 
              * Counter should be increased by a large amount, e.g. (0x10000000)
              * to outdo any previously lost/broken keys.
             */
             printf1(TAG_HID,"CTAPHID_LOADKEY\n");
-            if (len != 100)
+            if (len != 104)
             {
                 printf2(TAG_ERR,"Error, invalid length.\n");
                 ctaphid_send_error(wb->cid, CTAP1_ERR_INVALID_LENGTH);
                 return 1;
             }
+            param = ctap_buffer[0] << 16;
+            param |= ctap_buffer[1] << 8;
+            param |= ctap_buffer[2] << 0;
+            if (param != 0){
+                ctaphid_send_error(wb->cid, CTAP2_ERR_UNSUPPORTED_OPTION);
+                return 1;
+            }
 
             // Ask for THREE button presses
             if (ctap_user_presence_test(8000) > 0)
-                if (ctap_user_presence_test(8000) > 0)
-                    if (ctap_user_presence_test(8000) > 0)
+                if (ctap_user_presence_test(2000) > 0)
+                    if (ctap_user_presence_test(2000) > 0)
                     {
-                        ctap_load_external_keys(ctap_buffer + 4);
-                        param = ctap_buffer[3];
-                        param |= ctap_buffer[2] << 8;
-                        param |= ctap_buffer[1] << 16;
-                        param |= ctap_buffer[0] << 24;
+                        ctap_load_external_keys(ctap_buffer + 8);
+                        param = ctap_buffer[7];
+                        param |= ctap_buffer[6] << 8;
+                        param |= ctap_buffer[5] << 16;
+                        param |= ctap_buffer[4] << 24;
                         ctap_atomic_count(param);
 
                         wb->bcnt = 0;

fido2/ctaphid.h

@@ -27,6 +27,7 @@
 #define CTAPHID_BOOT            (TYPE_INIT | 0x50)
 #define CTAPHID_ENTERBOOT       (TYPE_INIT | 0x51)
 #define CTAPHID_ENTERSTBOOT     (TYPE_INIT | 0x52)
+#define CTAPHID_REBOOT          (TYPE_INIT | 0x53)
 #define CTAPHID_GETRNG          (TYPE_INIT | 0x60)
 #define CTAPHID_GETVERSION      (TYPE_INIT | 0x61)
 #define CTAPHID_LOADKEY         (TYPE_INIT | 0x62)

fido2/device.c

@@ -185,6 +185,22 @@ __attribute__((weak)) void ctap_store_rk(int index, CTAP_residentKey * rk)
 
 }
 
+__attribute__((weak)) void ctap_delete_rk(int index)
+{
+    CTAP_residentKey rk;
+    memset(&rk, 0xff, sizeof(CTAP_residentKey));
+
+    if (index < RK_NUM)
+    {
+        memmove(RK_STORE.rks + index, &rk, sizeof(CTAP_residentKey));
+    }
+    else
+    {
+        printf1(TAG_ERR,"Out of bounds for delete_rk\r\n");
+    }
+
+}
+
 __attribute__((weak)) void ctap_load_rk(int index, CTAP_residentKey * rk)
 {
     memmove(rk, RK_STORE.rks + index, sizeof(CTAP_residentKey));

fido2/device.h

@@ -140,6 +140,13 @@ uint32_t ctap_rk_size();
 */
 void ctap_store_rk(int index,CTAP_residentKey * rk);
 
+/** Delete a resident key from an index.
+ * @param index to delete resident key from.  Has no effect if no RK exists at index.
+ * 
+ * *Optional*, if not implemented, operates on non-persistant RK's.
+*/
+void ctap_delete_rk(int index);
+
 /** Read a resident key from an index into memory
  * @param index to read resident key from.
  * @param rk pointer to resident key structure to write into with RK.

fido2/log.c

@@ -51,6 +51,7 @@ struct logtag tagtable[] = {
     {TAG_NFC,"NFC"},
     {TAG_NFC_APDU, "NAPDU"},
     {TAG_CCID, "CCID"},
+    {TAG_CM, "CRED_MGMT"},
 };
 
 

fido2/log.h

@@ -48,6 +48,7 @@ typedef enum
     TAG_NFC      = (1 << 19),
     TAG_NFC_APDU = (1 << 20),
     TAG_CCID     = (1 << 21),
+    TAG_CM       = (1 << 22),
 
     TAG_NO_TAG   = (1UL << 30),
     TAG_FILENO   = (1UL << 31)

fido2/u2f.c

@@ -204,7 +204,7 @@ int8_t u2f_authenticate_credential(struct u2f_key_handle * kh, uint8_t key_handl
             printf1(TAG_U2F, "APPID does not match rpIdHash.\n");
             return 0;
         }
-        make_auth_tag(appid, cred->nonce, cred->count, tag);
+        make_auth_tag(appid, (uint8_t*)&cred->entropy, cred->count, tag);
 
         if (memcmp(cred->tag, tag, CREDENTIAL_TAG_SIZE) == 0){
             return 1;

fido2/version.c

@@ -1,4 +1,5 @@
 #include "version.h"
+#include "app.h"
 
 const version_t firmware_version 
 #ifdef SOLO

pc/device.c

@@ -449,6 +449,12 @@ void ctap_store_rk(int index, CTAP_residentKey * rk)
 
 }
 
+void ctap_delete_rk(int index)
+{
+    CTAP_residentKey rk;
+    memset(&rk, 0xff, sizeof(CTAP_residentKey));
+    memmove(RK_STORE.rks + index, &rk, sizeof(CTAP_residentKey));
+}
 
 void ctap_load_rk(int index, CTAP_residentKey * rk)
 {

targets/stm32l432/linker/stm32l4xx.ld

@@ -61,7 +61,7 @@ SECTIONS
         *(.data*)
         . = ALIGN(8);
         _edata = .;
-    } >ram AT> flash
+    } >sram2 AT> flash
 
     .flag :
     {

targets/stm32l432/src/device.c

@@ -577,7 +577,11 @@ uint32_t ctap_atomic_count(uint32_t amount)
         return lastc;
     }
 
+    if (amount > 256){
+        lastc = amount;
+    } else {
         lastc += amount;
+    }
 
     if (lastc/256 > erases)
     {
@@ -786,33 +790,28 @@ uint32_t ctap_rk_size(void)
 
 void ctap_store_rk(int index,CTAP_residentKey * rk)
 {
-    int page_offset = (sizeof(CTAP_residentKey) * index) / PAGE_SIZE;
-    uint32_t addr = flash_addr(page_offset + RK_START_PAGE) + ((sizeof(CTAP_residentKey)*index) % PAGE_SIZE);
-
-    printf1(TAG_GREEN, "storing RK %d @ %04x\r\n", index,addr);
-
-    if (page_offset < RK_NUM_PAGES)
-    {
-        flash_write(addr, (uint8_t*)rk, sizeof(CTAP_residentKey));
-        //dump_hex1(TAG_GREEN,rk,sizeof(CTAP_residentKey));
+    ctap_overwrite_rk(index, rk);
 }
-    else
+
+void ctap_delete_rk(int index)
 {
-        printf2(TAG_ERR,"Out of bounds reading index %d for rk\n", index);
-    }
+    CTAP_residentKey rk;
+    memset(&rk, 0xff, sizeof(CTAP_residentKey));
+    ctap_overwrite_rk(index, &rk);
 }
 
 void ctap_load_rk(int index,CTAP_residentKey * rk)
 {
-    int page_offset = (sizeof(CTAP_residentKey) * index) / PAGE_SIZE;
-    uint32_t addr = flash_addr(page_offset + RK_START_PAGE) + ((sizeof(CTAP_residentKey)*index) % PAGE_SIZE);
+    int byte_offset_into_page = (sizeof(CTAP_residentKey) * (index % (PAGE_SIZE/sizeof(CTAP_residentKey))));
+    int page_offset = (index)/(PAGE_SIZE/sizeof(CTAP_residentKey));
+
+    uint32_t addr = flash_addr(page_offset + RK_START_PAGE) + byte_offset_into_page;
 
     printf1(TAG_GREEN, "reading RK %d @ %04x\r\n", index, addr);
     if (page_offset < RK_NUM_PAGES)
     {
         uint32_t * ptr = (uint32_t *)addr;
         memmove((uint8_t*)rk,ptr,sizeof(CTAP_residentKey));
-        //dump_hex1(TAG_GREEN,rk,sizeof(CTAP_residentKey));
     }
     else
     {
@@ -823,22 +822,28 @@ void ctap_load_rk(int index,CTAP_residentKey * rk)
 void ctap_overwrite_rk(int index,CTAP_residentKey * rk)
 {
     uint8_t tmppage[PAGE_SIZE];
-    int page_offset = (sizeof(CTAP_residentKey) * index) / PAGE_SIZE;
-    int page = page_offset + RK_START_PAGE;
 
-    printf1(TAG_GREEN, "overwriting RK %d\r\n", index);
+    int byte_offset_into_page = (sizeof(CTAP_residentKey) * (index % (PAGE_SIZE/sizeof(CTAP_residentKey))));
+    int page_offset = (index)/(PAGE_SIZE/sizeof(CTAP_residentKey));
+
+    printf1(TAG_GREEN, "overwriting RK %d @ page %d @ addr 0x%08x-0x%08x\r\n", 
+        index, RK_START_PAGE + page_offset, 
+        flash_addr(RK_START_PAGE + page_offset) + byte_offset_into_page, 
+        flash_addr(RK_START_PAGE + page_offset) + byte_offset_into_page + sizeof(CTAP_residentKey) 
+        );
     if (page_offset < RK_NUM_PAGES)
     {
-        memmove(tmppage, (uint8_t*)flash_addr(page), PAGE_SIZE);
+        memmove(tmppage, (uint8_t*)flash_addr(RK_START_PAGE + page_offset), PAGE_SIZE);
 
-        memmove(tmppage + (sizeof(CTAP_residentKey) * index) % PAGE_SIZE, rk, sizeof(CTAP_residentKey));
-        flash_erase_page(page);
-        flash_write(flash_addr(page), tmppage, PAGE_SIZE);
+        memmove(tmppage + byte_offset_into_page, rk, sizeof(CTAP_residentKey));
+        flash_erase_page(RK_START_PAGE + page_offset);
+        flash_write(flash_addr(RK_START_PAGE + page_offset), tmppage, PAGE_SIZE);
     }
     else
     {
         printf2(TAG_ERR,"Out of bounds reading index %d for rk\n", index);
     }
+    printf1(TAG_GREEN, "4\r\n");
 }
 
 void boot_st_bootloader(void)