Add support for NAX0 input files.

Makefile

@@ -13,7 +13,7 @@ all:
 .c.o:
 	$(CC) $(INCLUDE) -c $(CFLAGS) -o $@ $<
 
-hactool: sha.o aes.o extkeys.o rsa.o npdm.o bktr.o kip.o packages.o pki.o pfs0.o hfs0.o romfs.o utils.o nca.o xci.o main.o filepath.o ConvertUTF.o
+hactool: sha.o aes.o extkeys.o rsa.o npdm.o bktr.o kip.o packages.o pki.o pfs0.o hfs0.o romfs.o utils.o nax0.o nca.o xci.o main.o filepath.o ConvertUTF.o
 	$(CC) -o $@ $^ $(LDFLAGS) -L $(LIBDIR)
 
 aes.o: aes.h types.h
@@ -36,6 +36,8 @@ pfs0.o: pfs0.h types.h
 
 pki.o: pki.h aes.h types.h
 
+nax0.o: nax0.h aes.h sha.h types.h
+
 nca.o: nca.h aes.h sha.h rsa.h bktr.h filepath.h types.h
 
 npdm.o: npdm.c types.h

extkeys.c

@@ -212,6 +212,15 @@ void extkeys_initialize_keyset(nca_keyset_t *keyset, FILE *f) {
             } else if (strcmp(key, "package2_key_source") == 0) {
                 parse_hex_key(keyset->package2_key_source, value, sizeof(keyset->package2_key_source));
                 matched_key = 1;
+            } else if (strcmp(key, "sd_card_kek_source") == 0) {
+                parse_hex_key(keyset->sd_card_kek_source, value, sizeof(keyset->sd_card_kek_source));
+                matched_key = 1;
+            } else if (strcmp(key, "sd_card_nca_key_source") == 0) {
+                parse_hex_key(keyset->sd_card_key_sources[1], value, sizeof(keyset->sd_card_key_sources[1]));
+                matched_key = 1;
+            } else if (strcmp(key, "sd_card_save_key_source") == 0) {
+                parse_hex_key(keyset->sd_card_key_sources[0], value, sizeof(keyset->sd_card_key_sources[0]));
+                matched_key = 1;
             } else {
                 char test_name[0x100];
                 memset(test_name, 0, sizeof(100));

main.c

@@ -9,6 +9,7 @@
 #include "pki.h"
 #include "nca.h"
 #include "xci.h"
+#include "nax0.h"
 #include "extkeys.h"
 #include "packages.h"
 
@@ -80,8 +81,11 @@ static void usage(void) {
         "  --extractini1      Enable INI1 extraction to default directory (redundant with --ini1dir set).\n"
         "  --ini1dir=dir      Specify INI1 directory path. Overrides default path, if present.\n"
         "INI1 options:\n"
-        "  --ini1dir=dir      Specify Package1 directory path.\n"
-        "  --outdir=dir       Specify Package1 directory path. Overrides previous path, if present.\n"
+        "  --ini1dir=dir      Specify INI1 directory path.\n"
+        "  --outdir=dir       Specify INI1 directory path. Overrides previous path, if present.\n"
+        "NAX0 options:\n"
+        "  --sdseed=seed      Set console unique seed for SD card NAX0 encryption.\n"
+        "  --sdpath=path      Set relative path for NAX0 key derivation (ex: /registered/000000FF/cafebabecafebabecafebabecafebabe.nca).\n"
         "\n", __TIME__, __DATE__, prog_name);
     exit(EXIT_FAILURE);
 }
@@ -152,6 +156,8 @@ int main(int argc, char **argv) {
             {"extractini1", 0, NULL, 29},
             {"basefake", 0, NULL, 30},
             {"onlyupdated", 0, NULL, 31},
+            {"sdseed", 1, NULL, 32},
+            {"sdpath", 1, NULL, 33},
             {NULL, 0, NULL, 0},
         };
 
@@ -201,6 +207,8 @@ int main(int argc, char **argv) {
                     nca_ctx.tool_ctx->file_type = FILETYPE_INI1;
                 } else if (!strcmp(optarg, "kip1") || !strcmp(optarg, "kip")) {
                     nca_ctx.tool_ctx->file_type = FILETYPE_KIP1;
+                } else if (!strcmp(optarg, "nax0") || !strcmp(optarg, "nax")) {
+                    nca_ctx.tool_ctx->file_type = FILETYPE_NAX0;
                 }
                 break;
             case 0: filepath_set(&nca_ctx.tool_ctx->settings.section_paths[0], optarg); break;
@@ -273,7 +281,7 @@ int main(int argc, char **argv) {
                 filepath_set(&tool_ctx.settings.out_dir_path.path, optarg); 
                 break;
             case 18:
-                filepath_set(&nca_ctx.tool_ctx->settings.dec_nca_path, optarg); 
+                filepath_set(&nca_ctx.tool_ctx->settings.plaintext_path, optarg); 
                 break;
             case 19:
                 filepath_set(&nca_ctx.tool_ctx->settings.header_path, optarg); 
@@ -319,6 +327,19 @@ int main(int argc, char **argv) {
             case 31:
                 tool_ctx.action |= ACTION_ONLYUPDATEDROMFS;
                 break;
+            case 32:
+                parse_hex_key(nca_ctx.tool_ctx->settings.sdseed, optarg, 16);
+                nca_ctx.tool_ctx->settings.has_sdseed = 1;
+                for (unsigned int key = 0; key < 2; key++) {
+                    for (unsigned int i = 0; i < 0x20; i++) {
+                        tool_ctx.settings.keyset.sd_card_key_sources[key][i] ^= tool_ctx.settings.sdseed[i & 0xF];
+                    }
+                }
+                pki_derive_keys(&tool_ctx.settings.keyset);
+                break;
+            case 33:
+                filepath_set(&tool_ctx.settings.nax0_sd_path, optarg);
+                break;
             default:
                 usage();
                 return EXIT_FAILURE;
@@ -364,6 +385,13 @@ int main(int argc, char **argv) {
 
     if (keyfile != NULL) {
         extkeys_initialize_keyset(&tool_ctx.settings.keyset, keyfile);
+        if (tool_ctx.settings.has_sdseed) {
+            for (unsigned int key = 0; key < 2; key++) {
+                for (unsigned int i = 0; i < 0x20; i++) {
+                    tool_ctx.settings.keyset.sd_card_key_sources[key][i] ^= tool_ctx.settings.sdseed[i & 0xF];
+                }
+            }
+        }
         pki_derive_keys(&tool_ctx.settings.keyset);
         fclose(keyfile);
     }
@@ -375,11 +403,37 @@ int main(int argc, char **argv) {
         usage();
     }
     
+    /* Special case NAX0. */
+    if (tool_ctx.file_type == FILETYPE_NAX0) {
+        nax0_ctx_t nax_ctx;
+        memset(&nax_ctx, 0, sizeof(nax_ctx));
+        filepath_set(&nax_ctx.base_path, input_name);
+        nax_ctx.tool_ctx = &tool_ctx;
+        nax0_process(&nax_ctx);
+    
+        if (nax_ctx.aes_ctx) {
+            free_aes_ctx(nax_ctx.aes_ctx);
+        }  
+        if (nax_ctx.num_files) {
+            for (unsigned int i = 0; i < nax_ctx.num_files; i++) {
+                fclose(nax_ctx.files[i]);
+            }
+        }
+        if (nax_ctx.files) {
+            free(nax_ctx.files);
+        }
+        printf("Done!\n");
+        return EXIT_SUCCESS;
+    } 
+    
+    
     if ((tool_ctx.file = fopen(input_name, "rb")) == NULL) {
         fprintf(stderr, "unable to open %s: %s\n", input_name, strerror(errno));
         return EXIT_FAILURE;
     }
 
+
+    
     switch (tool_ctx.file_type) {
         case FILETYPE_NCA: {
             if (nca_ctx.tool_ctx->base_nca_ctx != NULL) {

nax0.c

@@ -0,0 +1,168 @@
+#include <string.h>
+#include "aes.h"
+#include "sha.h"
+#include "nax0.h"
+
+size_t nax0_read(nax0_ctx_t *ctx, uint64_t offset, void *dst, size_t size) {
+    if (ctx->num_files == 1) {
+        fseeko64(ctx->files[0], offset, SEEK_SET);
+        return fread(dst, 1, size, ctx->files[0]);
+    }
+    
+    FILE *which = ctx->files[offset / 0xFFFF0000ULL];
+    uint64_t offset_in_file = offset % 0xFFFF0000ULL;
+    fseeko64(which, offset_in_file, SEEK_SET);
+    uint64_t left_in_file = 0xFFFF0000ULL - offset_in_file;
+    if (size > left_in_file) {
+        return fread(dst, 1, left_in_file, which) + nax0_read(ctx, offset + left_in_file, (unsigned char *)dst + left_in_file, size - left_in_file);
+    } else {
+        return fread(dst, 1, size, which);
+    }
+}
+
+void nax0_process(nax0_ctx_t *ctx) {
+    /* First things first... */
+    FILE *f_temp;
+    if ((f_temp = os_fopen(ctx->base_path.os_path, OS_MODE_READ)) != NULL) {
+        ctx->num_files = 1;
+        ctx->files = calloc(1, sizeof(FILE *));
+        if (ctx->files == NULL) {
+            fprintf(stderr, "Failed to allocate NAX0 file holder!\n");
+            exit(EXIT_FAILURE);
+        }
+        ctx->files[0] = f_temp;
+    } else {
+        ctx->num_files = 0;
+        filepath_t temp_path;
+        while (1) {
+            filepath_copy(&temp_path, &ctx->base_path);
+            filepath_append(&temp_path, "%02"PRIu32, ctx->num_files);
+            if ((f_temp = os_fopen(temp_path.os_path, OS_MODE_READ)) == NULL) {
+                break;
+            }
+            ctx->num_files++;
+            fclose(f_temp);
+        }
+        if (ctx->num_files == 0) {
+            fprintf(stderr, "Input path appears to neither be a NAX0, nor a NAX0 directory!\n");
+            exit(EXIT_FAILURE);
+        }
+        ctx->files = calloc(ctx->num_files, sizeof(FILE *));
+        if (ctx->files == NULL) {
+            fprintf(stderr, "Failed to allocate NAX0 file holder!\n");
+            exit(EXIT_FAILURE);
+        }
+        for (unsigned int i = 0; i < ctx->num_files; i++) {
+            filepath_copy(&temp_path, &ctx->base_path);
+            filepath_append(&temp_path, "%02"PRIu32, i);
+            if ((ctx->files[i] = os_fopen(temp_path.os_path, OS_MODE_READ)) == NULL) {
+                fprintf(stderr, "Failed to open %s!\n", temp_path.char_path);
+                exit(EXIT_FAILURE);
+            }
+        }
+    }
+    
+    nax0_read(ctx, 0, &ctx->header, sizeof(ctx->header));
+    if (ctx->header.magic != MAGIC_NAX0) {
+        printf("Error: File has invalid NAX0 magic!\n");
+        return;
+    }
+    
+    memcpy(ctx->encrypted_keys, ctx->header.keys, sizeof(ctx->header.keys));
+    
+    int found = 0;
+    for (ctx->k = 0; ctx->k < 2; ctx->k++) {
+        unsigned char nax_specific_keys[2][0x10];
+        sha256_get_buffer_hmac(nax_specific_keys, ctx->tool_ctx->settings.keyset.sd_card_keys[ctx->k], 0x10, ctx->tool_ctx->settings.nax0_sd_path.char_path, strlen(ctx->tool_ctx->settings.nax0_sd_path.char_path));
+        for (unsigned int i = 0; i < 2; i++) {
+            aes_ctx_t *nax_k_ctx = new_aes_ctx(nax_specific_keys[i], 0x10, AES_MODE_ECB);
+            aes_decrypt(nax_k_ctx, ctx->header.keys[i], ctx->encrypted_keys[i], 0x10);
+            free_aes_ctx(nax_k_ctx);
+        }
+        
+        unsigned char validation_mac[0x20];
+        sha256_get_buffer_hmac(validation_mac, &ctx->header.magic, 0x60, ctx->tool_ctx->settings.keyset.sd_card_keys[ctx->k] + 0x10, 0x10);
+        if (memcmp(ctx->header.hmac_header, validation_mac, 0x20) == 0) {
+            found = 1;
+            break;
+        }
+    }
+    
+    if (!found) {
+        printf("Error: NAX0 key derivation failed. Check SD card seed and relative path?\n");
+        return;
+    }
+    
+    ctx->aes_ctx = new_aes_ctx(ctx->header.keys, 0x20, AES_MODE_XTS);
+    
+    if (ctx->tool_ctx->action & ACTION_INFO) {
+        nax0_print(ctx);
+    }
+    
+    if (ctx->tool_ctx->action & ACTION_EXTRACT) {
+        nax0_save(ctx);
+    }
+}
+
+void nax0_save(nax0_ctx_t *ctx) {
+ /* Save Decrypted Contents. */
+    filepath_t *dec_path = &ctx->tool_ctx->settings.plaintext_path;
+
+    if (dec_path->valid == VALIDITY_VALID) {
+        printf("Saving Decrypted NAX0 Content to %s...\n", dec_path->char_path);
+        FILE *f_dec = os_fopen(dec_path->os_path, OS_MODE_WRITE);
+
+        if (f_dec != NULL) {
+            uint64_t ofs = 0x4000;
+            uint64_t end_ofs = ofs + ctx->header.size;
+            unsigned char *buf = malloc(0x400000);
+            if (buf == NULL) {
+                fprintf(stderr, "Failed to allocate file-save buffer!\n");
+                exit(EXIT_FAILURE);
+            }
+            
+            uint64_t read_size = 0x400000; /* 4 MB buffer. */
+            memset(buf, 0xCC, read_size); /* Debug in case I fuck this up somehow... */
+            while (ofs < end_ofs) {       
+                if (ofs + read_size >= end_ofs) read_size = end_ofs - ofs;
+                if (nax0_read(ctx, ofs, buf, read_size) != read_size) {
+                    fprintf(stderr, "Failed to read file!\n");
+                    exit(EXIT_FAILURE);
+                }
+                
+                aes_xts_decrypt(ctx->aes_ctx, buf, buf, read_size, (ofs - 0x4000) >> 14, 0x4000);
+                
+                if (fwrite(buf, 1, read_size, f_dec) != read_size) {
+                    fprintf(stderr, "Failed to write file!\n");
+                    exit(EXIT_FAILURE);
+                }
+                ofs += read_size;
+            }
+            
+            free(buf);
+        } else {
+            fprintf(stderr, "Failed to open %s!\n", dec_path->char_path);
+        }
+    }
+}
+
+const char *nax0_get_key_summary(unsigned int k) {
+    switch (k) {
+        case 0:
+            return "Save";
+        case 1:
+            return "NCA";
+        default:
+            return "Unknown";
+    }
+}
+
+void nax0_print(nax0_ctx_t *ctx) {
+    printf("\nNAX0:\n");
+    print_magic("    Magic:                          ", ctx->header.magic);
+    printf("    Content Type:                   %s\n", nax0_get_key_summary(ctx->k));
+    printf("    Content Size:                   %012"PRIx64"\n", ctx->header.size);
+    memdump(stdout, "    Header HMAC:                    ", ctx->header.hmac_header, 0x20);
+    memdump(stdout, "    Encrypted Keys:                 ", ctx->encrypted_keys, 0x20);
+    memdump(stdout, "    Decrypted Keys:                 ", ctx->header.keys, 0x20);
+}

nax0.h

@@ -0,0 +1,36 @@
+#ifndef HACTOOL_NAX0_H
+#define HACTOOL_NAX0_H
+
+#include <stdint.h>
+#include "types.h"
+#include "utils.h"
+#include "settings.h"
+#include "aes.h"
+
+#define MAGIC_NAX0 0x3058414E
+
+typedef struct {
+    uint8_t hmac_header[0x20];
+    uint32_t magic;
+    uint32_t _0x24;
+    uint8_t keys[2][0x10];
+    uint64_t size;
+    uint8_t _0x50[0x30];
+} nax0_header_t;
+
+typedef struct {
+    filepath_t base_path;
+    hactool_ctx_t *tool_ctx;
+    aes_ctx_t *aes_ctx;
+    FILE **files;
+    unsigned int num_files;
+    unsigned int k;
+    unsigned char encrypted_keys[2][0x10];
+    nax0_header_t header;
+} nax0_ctx_t;
+
+void nax0_process(nax0_ctx_t *ctx);
+void nax0_save(nax0_ctx_t *ctx);
+void nax0_print(nax0_ctx_t *ctx);
+
+#endif

nca.c

@@ -316,7 +316,7 @@ void nca_save(nca_ctx_t *ctx) {
     }
     
     /* Save Decrypted NCA. */
-    filepath_t *dec_path = &ctx->tool_ctx->settings.dec_nca_path;
+    filepath_t *dec_path = &ctx->tool_ctx->settings.plaintext_path;
 
     if (dec_path->valid == VALIDITY_VALID) {
         printf("Saving Decrypted NCA to %s...\n", dec_path->char_path);

pki.c

@@ -114,6 +114,11 @@ const nca_keyset_t nca_keys_retail = {
     ZEROES_KEY, /* Key Area Encryption Key Source System */
     ZEROES_KEY, /* Titlekek Source */
     ZEROES_KEY, /* Headerkek Source */
+    ZEROES_KEY, /* SD Card kek Source. */
+    {
+        ZEROES_XTS_KEY, /* SD Card Key Source, for NCAs. */
+        ZEROES_XTS_KEY, /* SD Card Key Source, for saves. */
+    },
     ZEROES_XTS_KEY, /* Encrypted Header Key */
     ZEROES_XTS_KEY, /* Header key */
     {
@@ -184,6 +189,10 @@ const nca_keyset_t nca_keys_retail = {
         ZEROES_KAEKS, /* Key Area Encryption Keyset 30 */
         ZEROES_KAEKS  /* Key Area Encryption Keyset 31 */
     },
+    {
+        ZEROES_XTS_KEY, /* SD Card Key, for NCAs. */
+        ZEROES_XTS_KEY, /* SD Card Key, for saves. */
+    },
     { /* Fixed RSA key used to validate NCA signature 0. */
         0xBF, 0xBE, 0x40, 0x6C, 0xF4, 0xA7, 0x80, 0xE9, 0xF0, 0x7D, 0x0C, 0x99, 0x61, 0x1D, 0x77, 0x2F,
         0x96, 0xBC, 0x4B, 0x9E, 0x58, 0x38, 0x1B, 0x03, 0xAB, 0xB1, 0x75, 0x49, 0x9F, 0x2B, 0x4D, 0x58,
@@ -351,6 +360,11 @@ const nca_keyset_t nca_keys_dev = {
     ZEROES_KEY, /* Key Area Encryption Key Source System */
     ZEROES_KEY, /* Titlekek Source */
     ZEROES_KEY, /* Headerkek Source */
+    ZEROES_KEY, /* SD Card kek Source. */
+    {
+        ZEROES_XTS_KEY, /* SD Card Key Source, for NCAs. */
+        ZEROES_XTS_KEY, /* SD Card Key Source, for saves. */
+    },
     ZEROES_XTS_KEY, /* Encrypted Header Key */
     ZEROES_XTS_KEY, /* Header key */
     {
@@ -421,6 +435,10 @@ const nca_keyset_t nca_keys_dev = {
         ZEROES_KAEKS, /* Key Area Encryption Keyset 30 */
         ZEROES_KAEKS  /* Key Area Encryption Keyset 31 */
     },
+    {
+        ZEROES_XTS_KEY, /* SD Card Key, for NCAs. */
+        ZEROES_XTS_KEY, /* SD Card Key, for saves. */
+    },
     {
         0xD8, 0xF1, 0x18, 0xEF, 0x32, 0x72, 0x4C, 0xA7, 0x47, 0x4C, 0xB9, 0xEA, 0xB3, 0x04, 0xA8, 0xA4,
         0xAC, 0x99, 0x08, 0x08, 0x04, 0xBF, 0x68, 0x57, 0xB8, 0x43, 0x94, 0x2B, 0xC7, 0xB9, 0x66, 0x49,
@@ -539,6 +557,21 @@ void pki_derive_keys(nca_keyset_t *keyset) {
             free_aes_ctx(header_ctx);
         }
         
+        /* Derive SD Card Key */
+        if (i == 0 && memcmp(keyset->sd_card_kek_source, zeroes, 0x10) != 0) {
+            unsigned char sd_kek[0x10];
+            generate_kek(sd_kek, keyset->sd_card_kek_source, keyset->master_keys[i], keyset->aes_kek_generation_source, keyset->aes_key_generation_source);
+            aes_ctx_t *sd_ctx = new_aes_ctx(sd_kek, 0x10, AES_MODE_ECB);
+
+            for (unsigned int k = 0; k < 2; k++) {
+                if (memcmp(keyset->sd_card_key_sources[k], zeroes, 0x20) != 0) {
+                    aes_decrypt(sd_ctx, keyset->sd_card_keys[k], keyset->sd_card_key_sources[k], 0x20);
+                }
+            }
+            
+            free_aes_ctx(sd_ctx);
+        }
+        
         free_aes_ctx(master_ctx);
     }
 
@@ -558,5 +591,4 @@ void pki_initialize_keyset(nca_keyset_t *keyset, keyset_variant_t variant) {
     }
     
     pki_derive_keys(keyset);
-    
 }

settings.h

@@ -27,10 +27,13 @@ typedef struct {
     unsigned char key_area_key_system_source[0x10];      /* Seed for kaek 2. */
     unsigned char titlekek_source[0x10];                 /* Seed for titlekeks. */
     unsigned char header_kek_source[0x10];               /* Seed for header kek. */
+    unsigned char sd_card_kek_source[0x10];              /* Seed for SD card kek. */
+    unsigned char sd_card_key_sources[2][0x20];           /* Seed for SD card encryption keys. */
     unsigned char encrypted_header_key[0x20];            /* Actual encrypted header key. */
     unsigned char header_key[0x20];                      /* NCA header key. */
     unsigned char titlekeks[0x20][0x10];                 /* Title key encryption keys. */
     unsigned char key_area_keys[0x20][3][0x10];          /* Key area encryption keys. */
+    unsigned char sd_card_keys[2][0x20];
     unsigned char nca_hdr_fixed_key_modulus[0x100];      /* NCA header fixed key RSA pubk. */
     unsigned char acid_fixed_key_modulus[0x100];         /* ACID fixed key RSA pubk. */
     unsigned char package2_fixed_key_modulus[0x100];     /* Package2 Header RSA pubk. */
@@ -48,6 +51,8 @@ typedef struct {
     unsigned char dec_titlekey[0x10];
     int has_contentkey;
     unsigned char contentkey[0x10];
+    int has_sdseed;
+    unsigned char sdseed[0x10];
     filepath_t section_paths[4];
     filepath_t section_dir_paths[4];
     override_filepath_t exefs_path;
@@ -60,12 +65,14 @@ typedef struct {
     filepath_t pk11_dir_path;
     filepath_t pk21_dir_path;
     filepath_t ini1_dir_path;
-    filepath_t dec_nca_path;
+    filepath_t plaintext_path;
     filepath_t rootpt_dir_path;
     filepath_t update_dir_path;
     filepath_t normal_dir_path;
     filepath_t secure_dir_path;
     filepath_t header_path;
+    filepath_t nax0_path;
+    filepath_t nax0_sd_path;
 } hactool_settings_t;
 
 enum hactool_file_type
@@ -79,7 +86,8 @@ enum hactool_file_type
     FILETYPE_PACKAGE1,
     FILETYPE_PACKAGE2,
     FILETYPE_INI1,
-    FILETYPE_KIP1
+    FILETYPE_KIP1,
+    FILETYPE_NAX0
 };
 
 #define ACTION_INFO (1<<0)

sha.c

@@ -53,3 +53,33 @@ void sha256_hash_buffer(unsigned char *digest, const void *data, size_t l) {
     sha_get_hash(sha_ctx, digest);
     free_sha_ctx(sha_ctx);
 }
+
+/* SHA256-HMAC digest. */
+void sha256_get_buffer_hmac(void *digest, const void *secret, size_t s_l, const void *data, size_t d_l) {
+    sha_ctx_t *ctx;
+    
+    if ((ctx = malloc(sizeof(*ctx))) == NULL) {
+        FATAL_ERROR("Failed to allocate sha_ctx_t!");
+    }
+    
+    mbedtls_md_init(&ctx->digest);
+    
+    if (mbedtls_md_setup(&ctx->digest, mbedtls_md_info_from_type(HASH_TYPE_SHA256), 1)) {
+        FATAL_ERROR("Failed to set up hash context!");
+    }
+    
+    if (mbedtls_md_hmac_starts(&ctx->digest, secret, s_l)) {
+        FATAL_ERROR("Failed to set up HMAC secret context!");
+    }
+    
+    if (mbedtls_md_hmac_update(&ctx->digest, data, d_l)) {
+        FATAL_ERROR("Failed processing HMAC input!");
+    }
+    
+    if (mbedtls_md_hmac_finish(&ctx->digest, digest)) {
+        FATAL_ERROR("Failed getting HMAC output!");
+    }
+    
+    mbedtls_md_free(&ctx->digest);
+    free(ctx);
+}

sha.h

@@ -22,4 +22,6 @@ void free_sha_ctx(sha_ctx_t *ctx);
 
 void sha256_hash_buffer(unsigned char *digest, const void *data, size_t l);
 
+void sha256_get_buffer_hmac(void *digest, const void *secret, size_t s_l, const void *data, size_t d_l);
+
 #endif