authenticate keys against a json document.

Change-Id: I988ccef75bf3f1def40893aa506d169a3926e32a
Signed-off-by: Loïc Collignon <loic.collignon@iot.bzh>

diff --git a/pam_agl/pam_agl.c b/pam_agl/pam_agl.c
index 3e246e4..0eea11a 100644 (file)
--- a/pam_agl/pam_agl.c
+++ b/pam_agl/pam_agl.c
@@ -15,6 +15,8 @@
 #include <security/pam_modules.h>
 #include <security/pam_appl.h>
 
+#define DATABASE_FILE "/etc/agl/keys.json"
+
 #define BLOCK_SIZE 4096
 typedef struct header_
 {
@@ -27,6 +29,37 @@ int is_valid_mn(const char* v)
        return v && v[0] == 'I' && v[1] == 'D' && v[2] == 'K' && v[3] == 'Y';
 }
 
+char* get_file_content(const char* path)
+{
+       char* buffer;
+       long length;
+       FILE* f;
+       
+       buffer = NULL;
+       length = 0;
+       
+       f = fopen(path, "rb");
+       if (f)
+       {
+               fseek(f, 0, SEEK_END);
+               length = ftell(f);
+               fseek(f, 0, SEEK_SET);
+               buffer = malloc(length + 1);
+               if (buffer)
+               {
+                       if (fread (buffer, 1, length, f) != length)
+                       {
+                               free(buffer);
+                               buffer = NULL;
+                       }
+                       else buffer[length] = 0;
+               }
+               fclose (f);
+       }
+       
+       return buffer;
+}
+
 void pam_putenv_ex(pam_handle_t* pamh, const char* name, const char* value)
 {
        char result[4096];
@@ -40,77 +73,120 @@ void pam_putenv_ex(pam_handle_t* pamh, const char* name, const char* value)
        pam_putenv(pamh, result);
 }
 
-int check_device(pam_handle_t* pamh, const char* device)
+int read_device(const char* device, char** idkey)
 {
-       printf("[PAM DEBUG]: check_device %s...\n", device);
-       int fd = open(device, O_RDONLY);
+       int fd;
+       ssize_t sz;
+       header h;
+               
+       printf("[PAM DEBUG] check_device %s...\n", device);
+       fd = open(device, O_RDONLY);
        if (fd == -1)
        {
-               printf("[PAM DEBUG]: Failed to open the device %s!\n", device);
+               printf("[PAM DEBUG] Failed to open the device %s!\n", device);
                return PAM_SERVICE_ERR;
        }
 
-       header h;
-       ssize_t sz = read(fd, &h, sizeof(header));
+       sz = read(fd, &h, sizeof(header));
        if (sz != sizeof(header) || !is_valid_mn(h.mn) || h.size < 1) { close(fd); printf("[PAM DEBUG]: bad header!\n"); return PAM_SERVICE_ERR; }
-       printf("[PAM DEBUG]: data size=%d\n", h.size);
+       printf("[PAM DEBUG]: data size=%lu\n", h.size);
 
-       char* idkey = (char*)malloc(h.size + 1);
-       if (!idkey) { close(fd); printf("[PAM DEBUG] Bad alloc!\n"); return PAM_SERVICE_ERR; }
+       *idkey = (char*)malloc(h.size + 1);
+       if (!*idkey) { close(fd); printf("[PAM DEBUG] Bad alloc!\n"); return PAM_SERVICE_ERR; }
 
-       memset(idkey, 0, h.size + 1);
-       size_t count = read(fd, idkey, h.size);
+       memset(*idkey, 0, h.size + 1);
+       sz = read(fd, *idkey, h.size);
        close(fd);
+       if (sz != h.size) { free(idkey); printf("[PAM DEBUG] Bad data read!\n"); return PAM_SERVICE_ERR; }
+       return PAM_SUCCESS;
+}
 
-       if (count != h.size) { free(idkey); printf("[PAM DEBUG] Bad data read!\n"); return PAM_SERVICE_ERR; }
-       printf("[PAM DEBUG] Data read:\n%s\n", idkey);
+int authenticate(pam_handle_t* pamh, const char* uuid)
+{
+       char* file_content;
+       struct json_object* database;
+       struct json_object* key;
+
+       file_content = get_file_content(DATABASE_FILE);
+       if (!file_content)
+       {
+               printf("[PAM DEBUG] Failed to read database file (%s)\n", DATABASE_FILE);
+               return PAM_SERVICE_ERR;
+       }
+       
+       database = json_tokener_parse(file_content);
+       if (!database)
+       {
+               printf("[PAM DEBUG] Failed to parse the database\n");
+               return PAM_SERVICE_ERR;
+       }
+       
+       if (json_object_object_get_ex(database, uuid, &key))
+       {
+               printf("[PAM] Key found!\n");
+               printf("[PAM DEBUG] pam_set_item(\"%s\")\n", uuid);
+               pam_set_item(pamh, PAM_USER, uuid);
+                       
+               const char* pam_authtok;
+               if (pam_get_item(pamh, PAM_AUTHTOK, (const void**)&pam_authtok) == PAM_SUCCESS && !pam_authtok)
+                       pam_set_item(pamh, PAM_AUTHTOK, uuid);
+               
+               json_object_put(database);
+               free(file_content);
+               return PAM_SUCCESS;
+       }
+       
+       printf("[PAM] Key not found!\n");
+       free(file_content);
+       if (database) json_object_put(database);
+       return PAM_AUTH_ERR;
+}
 
+int check_device(pam_handle_t* pamh, const char* device)
+{
+       char* idkey;
+       int ret;
+       
+       ret = read_device(device, &idkey);
+       if (ret != PAM_SUCCESS) return ret;
+       
+       printf("[PAM DEBUG] Data read:\n%s\n", idkey);
+       
        json_object* idkey_json = json_tokener_parse(idkey);
-       if (!idkey_json) { free(idkey); printf("[PAM DEBUG] Failed to parse json data!\n"); return PAM_SERVICE_ERR; }
+       if (!idkey_json)
+       {
+               free(idkey);
+               printf("[PAM DEBUG] Failed to parse json data!\n");
+               return PAM_SERVICE_ERR;
+       }
 
        json_object* uuid_json;
-       if(!json_object_object_get_ex(idkey_json, "uuid", &uuid_json)) { free(idkey); printf("[PAM DEBUG]: The json does not contains a valid uuid\n"); return PAM_SERVICE_ERR; }
+       if(!json_object_object_get_ex(idkey_json, "uuid", &uuid_json))
+       {
+               free(idkey);
+               printf("[PAM DEBUG] The json does not contains a valid uuid\n");
+               return PAM_SERVICE_ERR;
+       }
 
        const char* uuid = json_object_get_string(uuid_json);
        printf("[PAM DEBUG] uuid: %s\n", uuid);
-
-       // TODO: Check if the uuid is accepted
-       const char* const ids[] = {
-               "4f29e9ea-600a-11e7-8331-c70192ecfa55",
-               "13126524-6256-11e7-be33-3f4e4481a8c9",
-               NULL
-       };
-
-       int i = 0;
-       while(ids[i])
-       {
-               if (!strcmp(ids[i], uuid))
-               {
-                       printf("[PAM DEBUG] pam_set_item(\"%s\")\n", uuid);
-                       pam_set_item(pamh, PAM_USER, uuid);
-                       
-                       const char* pam_authtok;
-                       if (pam_get_item(pamh, PAM_AUTHTOK, (const void**)&pam_authtok) == PAM_SUCCESS && !pam_authtok)
-                               pam_set_item(pamh, PAM_AUTHTOK, uuid);
-
-                       return PAM_SUCCESS;
-               }
-               ++i;
-       }
        
-       return PAM_AUTH_ERR;
+       ret = authenticate(pamh, uuid);
+       free(idkey);
+       json_object_put(idkey_json);
+       return ret;
 }
 
 void log_pam(const char* fname, int flags, int argc, const char** argv, const char* device)
 {
-       printf("[PAM DEBUG]: ---------- %s ----------\n", fname);
-       printf("[PAM DEBUG]: flags: %d\n", flags);
+       printf("[PAM DEBUG] ---------- %s ----------\n", fname);
+       printf("[PAM DEBUG] flags: %d\n", flags);
        for(int i = 0; i < argc; ++i)
        {
-               printf("[PAM DEBUG]: argv[%d]: %s\n", i, argv[i]);
+               printf("[PAM DEBUG] argv[%d]: %s\n", i, argv[i]);
        }
-       printf("[PAM DEBUG]: device: %s\n", device);
-       printf("[PAM DEBUG]: ----------------------------------------\n");
+       printf("[PAM DEBUG] device: %s\n", device);
+       printf("[PAM DEBUG] ----------------------------------------\n");
 }
 
 /*!