From d0f7935f637df5d4794aa782def96cc3db8779ed Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Wed, 16 Oct 2013 19:30:17 -0500
Subject: Prep work for useradd by Ashwini Sharma.

---
 lib/lib.h         |   5 ++
 lib/password.c    | 172 ++++++++++++++++++++++++++++++++++++++++++++----------
 toys/lsb/passwd.c | 113 ++++++++---------------------------
 3 files changed, 172 insertions(+), 118 deletions(-)

diff --git a/lib/lib.h b/lib/lib.h
index fe494e72..ef688a32 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -187,6 +187,11 @@ mode_t string_to_mode(char *mode_str, mode_t base);
 void mode_to_string(mode_t mode, char *buf);
 
 // password helper functions
+#define MAX_SALT_LEN  20 //3 for id, 16 for key, 1 for '\0'
+#define SYS_FIRST_ID  100
+#define SYS_LAST_ID   999
+int get_salt(char *salt, char * algo);
+void is_valid_username(const char *name);
 int read_password(char * buff, int buflen, char* mesg);
 int update_password(char *filename, char* username, char* encrypted);
 
diff --git a/lib/password.c b/lib/password.c
index d1489eb3..b340ef48 100644
--- a/lib/password.c
+++ b/lib/password.c
@@ -1,19 +1,87 @@
-/* pwdutils.c - password read/update helper functions.
+/* password.c - password read/update helper functions.
  *
  * Copyright 2012 Ashwini Kumar <ak.ashwini@gmail.com>
  */
 
 #include "toys.h"
+#include "xregcomp.h"
 #include <time.h>
 
+static unsigned int random_number_generator(int fd)
+{      
+  unsigned int randnum;
+
+  xreadall(fd, &randnum, sizeof(randnum));
+  return randnum;
+}      
+       
+static char inttoc(int i)
+{      
+  // salt value uses 64 chracters in "./0-9a-zA-Z"
+  const char character_set[]="./0123456789abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+  i &= 0x3f; // masking for using 10 bits only
+  return character_set[i];
+}      
+       
+int get_salt(char *salt, char *algo)
+{      
+  int i, randfd, salt_length = 0, offset;
+
+  if (!strcmp(algo,"des")){
+    // 2 bytes salt value is used in des
+    salt_length = 2;
+    offset = 0;
+  } else {
+    *salt++ = '$';
+    if (!strcmp(algo,"md5")){
+      *salt++ = '1';
+      // 8 bytes salt value is used in md5
+      salt_length = 8;
+    } else if (!strcmp(algo,"sha256")){
+      *salt++ = '5';
+      // 16 bytes salt value is used in sha256
+      salt_length = 16;
+    } else if (!strcmp(algo,"sha512")){
+      *salt++ = '6';
+      // 16 bytes salt value is used in sha512
+      salt_length = 16;
+    } else return -1;
+
+    *salt++ = '$';
+    offset = 3;
+  }    
+
+  randfd = xopen("/dev/urandom", O_RDONLY);
+  for (i=0; i<salt_length; i++)
+    salt[i] = inttoc(random_number_generator(randfd));
+  salt[salt_length+1] = '\0';
+  xclose(randfd);
+
+  return offset;
+}
+
+static void handle(int signo)
+{
+  //Dummy.. so that read breaks on the signal, 
+  //instead of the applocation exit
+}
+
 int read_password(char * buff, int buflen, char* mesg)
 {
   int i = 0;
   struct termios termio, oldtermio;
+  struct sigaction sa, oldsa;
+
   tcgetattr(0, &oldtermio);
   tcflush(0, TCIFLUSH);
   termio = oldtermio;
 
+  memset(&sa, 0, sizeof(sa));
+  sa.sa_handler = handle;
+  sigaction(SIGINT, &sa, &oldsa);
+
   termio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
   termio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
   tcsetattr(0, TCSANOW, &termio);
@@ -25,7 +93,10 @@ int read_password(char * buff, int buflen, char* mesg)
     int ret = read(0, &buff[i], 1);
     if ( ret < 0 ) {
       buff[0] = 0;
+      sigaction(SIGINT, &oldsa, NULL);
       tcsetattr(0, TCSANOW, &oldtermio);
+      xputc('\n');
+      fflush(stdout);
       return 1;
     } else if (ret == 0 || buff[i] == '\n' || buff[i] == '\r' || buflen == i+1)
     {
@@ -34,35 +105,45 @@ int read_password(char * buff, int buflen, char* mesg)
     }
     i++;
   }
-
+  sigaction(SIGINT, &oldsa, NULL);
   tcsetattr(0, TCSANOW, &oldtermio);
   puts("");
   fflush(stdout);
   return 0;
 }
 
-static char *get_nextcolon(const char *line, char delim)
+static char *get_nextcolon(char *line, int cnt)
 {
-  char *current_ptr = NULL;
-  if((current_ptr = strchr(line, ':')) == NULL) error_exit("Invalid Entry\n");
-  return current_ptr;
+  while (cnt--) {
+    if (!(line = strchr(line, ':'))) error_exit("Invalid Entry\n");
+    line++; //jump past the colon
+  }
+  return line;
 }
 
-int update_password(char *filename, char* username, char* encrypted)
+/*update_password is used by multiple utilities to update /etc/passwd,
+ * /etc/shadow, /etc/group and /etc/gshadow files, 
+ * which are used as user, group databeses
+ * entry can be 
+ * 1. encrypted password, when updating user password.
+ * 2. complete entry for user details, when creating new user
+ * 3. group members comma',' separated list, when adding user to group
+ * 4. complete entry for group details, when creating new group
+ */
+int update_password(char *filename, char* username, char* entry)
 {
-  char *filenamesfx = NULL, *namesfx = NULL;
-  char *shadow = NULL, *sfx = NULL;
+  char *filenamesfx = NULL, *namesfx = NULL, *shadow = NULL,
+       *sfx = NULL, *line = NULL;
   FILE *exfp, *newfp;
-  int ret = -1; //fail
+  int ret = -1, found = 0;
   struct flock lock;
-  char *line = NULL;
 
   shadow = strstr(filename, "shadow");
   filenamesfx = xmsprintf("%s+", filename);
   sfx = strchr(filenamesfx, '+');
 
   exfp = fopen(filename, "r+");
-  if(!exfp) {
+  if (!exfp) {
     perror_msg("Couldn't open file %s",filename);
     goto free_storage;
   }
@@ -70,7 +151,7 @@ int update_password(char *filename, char* username, char* encrypted)
   *sfx = '-';
   ret = unlink(filenamesfx);
   ret = link(filename, filenamesfx);
-  if(ret < 0) error_msg("can't create backup file");
+  if (ret < 0) error_msg("can't create backup file");
 
   *sfx = '+';
   lock.l_type = F_WRLCK;
@@ -79,12 +160,12 @@ int update_password(char *filename, char* username, char* encrypted)
   lock.l_len = 0;
 
   ret = fcntl(fileno(exfp), F_SETLK, &lock);
-  if(ret < 0) perror_msg("Couldn't lock file %s",filename);
+  if (ret < 0) perror_msg("Couldn't lock file %s",filename);
 
   lock.l_type = F_UNLCK; //unlocking at a later stage
 
   newfp = fopen(filenamesfx, "w+");
-  if(!newfp) {
+  if (!newfp) {
     error_msg("couldn't open file for writing");
     ret = -1;
     fclose(exfp);
@@ -93,29 +174,34 @@ int update_password(char *filename, char* username, char* encrypted)
 
   ret = 0;
   namesfx = xmsprintf("%s:",username);
-  while((line = get_line(fileno(exfp))) != NULL)
+  while ((line = get_line(fileno(exfp))) != NULL)
   {
-    if(strncmp(line, namesfx, strlen(namesfx)) != 0)
+    if (strncmp(line, namesfx, strlen(namesfx)))
       fprintf(newfp, "%s\n", line);
     else {
       char *current_ptr = NULL;
-      fprintf(newfp, "%s%s:",namesfx,encrypted);
-      current_ptr = get_nextcolon(line, ':'); //past username
-      current_ptr++; //past colon ':' after username
-      current_ptr = get_nextcolon(current_ptr, ':'); //past passwd
-      current_ptr++; //past colon ':' after passwd
-      if(shadow) {
-        fprintf(newfp, "%u:",(unsigned)(time(NULL))/(24*60*60));
-        current_ptr = get_nextcolon(current_ptr, ':');
-        current_ptr++; //past time stamp colon.
-        fprintf(newfp, "%s\n",current_ptr);
+
+      found = 1;
+      if (!strcmp(toys.which->name, "passwd")) {
+        fprintf(newfp, "%s%s:",namesfx, entry);
+        current_ptr = get_nextcolon(line, 2); //past passwd
+        if (shadow) {
+          fprintf(newfp, "%u:",(unsigned)(time(NULL))/(24*60*60));
+          current_ptr = get_nextcolon(current_ptr, 1);
+          fprintf(newfp, "%s\n",current_ptr);
+        } else fprintf(newfp, "%s\n",current_ptr);
+      } else if (!strcmp(toys.which->name, "groupadd") || 
+          !strcmp(toys.which->name, "addgroup")){
+        current_ptr = get_nextcolon(line, 3); //past gid/admin list
+        *current_ptr = '\0';
+        fprintf(newfp, "%s", line);
+        fprintf(newfp, "%s\n", entry);
       }
-      else fprintf(newfp, "%s\n",current_ptr);
     }
-
     free(line);
   }
   free(namesfx);
+  if (!found) fprintf(newfp, "%s\n", entry);
   fcntl(fileno(exfp), F_SETLK, &lock);
   fclose(exfp);
 
@@ -124,7 +210,7 @@ int update_password(char *filename, char* username, char* encrypted)
   fsync(fileno(newfp));
   fclose(newfp);
   rename(filenamesfx, filename);
-  if(errno) {
+  if (errno) {
     perror_msg("File Writing/Saving failed: ");
     unlink(filenamesfx);
     ret = -1;
@@ -134,3 +220,29 @@ free_storage:
   free(filenamesfx);
   return ret;
 }
+
+void is_valid_username(const char *name)                                                                                              
+{
+  regex_t rp;
+  regmatch_t rm[1]; 
+  int eval;
+  char *regex = "^[_.A-Za-z0-9][-_.A-Za-z0-9]*"; //User name REGEX
+
+  xregcomp(&rp, regex, REG_NEWLINE);
+
+  /* compare string against pattern --  remember that patterns 
+     are anchored to the beginning of the line */
+  eval = regexec(&rp, name, 1, rm, 0);
+  regfree(&rp);
+  if (!eval && !rm[0].rm_so) {
+    int len = strlen(name);
+    if ((rm[0].rm_eo == len) ||
+        (rm[0].rm_eo == len - 1 && name[len - 1] == '$')) {
+      if (len >= LOGIN_NAME_MAX) error_exit("name is too long");
+      else return;
+    }
+  }
+  error_exit("'%s', not valid %sname",name,
+      (((toys.which->name[3] == 'g') || 
+        (toys.which->name[0] == 'g'))? "group" : "user"));
+}
diff --git a/toys/lsb/passwd.c b/toys/lsb/passwd.c
index 167d5730..1784c049 100644
--- a/toys/lsb/passwd.c
+++ b/toys/lsb/passwd.c
@@ -11,9 +11,9 @@ config PASSWD
   bool "passwd"
   default y
   help
-    usage: passwd [-a ALGO] [-d] [-l] [-u] <account name>
+    usage: passwd [-a ALGO] [-dlu] <account name>
 
-    update user’s authentication tokens. Default : current user
+    update user's authentication tokens. Default : current user
 
     -a ALGO	Encryption method (des, md5, sha256, sha512) default: des
     -d		Set password to ''
@@ -23,81 +23,25 @@ config PASSWD
 
 #define FOR_passwd
 #include "toys.h"
-#include <time.h>
 
 GLOBALS(
   char *algo;
 )
 
-#define MAX_SALT_LEN  20 //3 for id, 16 for key, 1 for '\0'
-#define URANDOM_PATH    "/dev/urandom"
-
 #ifndef _GNU_SOURCE
 char *strcasestr(const char *haystack, const char *needle);
 #endif
 
-unsigned int random_number_generator(int fd)
-{
-  unsigned int randnum;
-
-  xreadall(fd, &randnum, sizeof(randnum));
-  return randnum;
-}
-
-char inttoc(int i)
-{
-  // salt value uses 64 chracters in "./0-9a-zA-Z"
-  const char character_set[]="./0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
-
-  i &= 0x3f; // masking for using 10 bits only
-  return character_set[i];
-}
-
-int get_salt(char *salt)
-{
-  int i, salt_length = 0;
-  int randfd;
-
-  if (!strncmp(TT.algo,"des",3)) {
-    // 2 bytes salt value is used in des
-    salt_length = 2;
-  } else {
-    *salt++ = '$';
-    if (!strncmp(TT.algo,"md5",3)) {
-      *salt++ = '1';
-      // 8 bytes salt value is used in md5
-      salt_length = 8;
-    } else if (!strncmp(TT.algo,"sha256",6)) {
-      *salt++ = '5';
-      // 16 bytes salt value is used in sha256
-      salt_length = 16;
-    } else if (!strncmp(TT.algo,"sha512",6)) {
-      *salt++ = '6';
-      // 16 bytes salt value is used in sha512
-      salt_length = 16;
-    } else return 1;
-
-    *salt++ = '$';
-  }
-
-  randfd = xopen(URANDOM_PATH, O_RDONLY);
-  for (i=0; i<salt_length; i++)
-    salt[i] = inttoc(random_number_generator(randfd));
-  salt[salt_length+1] = '\0';
-  xclose(randfd);
-
-  return 0;
-}
-
 static int str_check(char *s, char *p)
 {
-  if ((strcasestr(s, p) != NULL) || (strcasestr(p, s) != NULL)) return 1;
+  if (strcasestr(s, p) || strcasestr(p, s)) return 1;
   return 0;
 }
 
 static void strength_check(char *newp, char *oldp, char *user)
 {
   char *msg = NULL;
+
   if (strlen(newp) < 6) { //Min passwd len
     msg = "too short";
     xprintf("BAD PASSWORD: %s\n",msg);
@@ -123,7 +67,7 @@ static int verify_passwd(char * pwd)
   if (pwd[0] == '!' || pwd[0] == '*') return 1;
 
   pass = crypt(toybuf, pwd);
-  if (pass != NULL && strcmp(pass, pwd)==0) return 0;
+  if (pass  && !strcmp(pass, pwd)) return 0;
 
   return 1;
 }
@@ -142,32 +86,27 @@ static char *new_password(char *oldp, char *user)
     return NULL; //may be due to Ctrl-C
   }
 
-  if (strcmp(newp, toybuf) == 0) return newp;
+  if (!strcmp(newp, toybuf)) return newp;
   else error_msg("Passwords do not match.\n");
-  /*Failure Case */
+  // Failure Case
   free(newp);
-
   return NULL;
 }
 
-
 void passwd_main(void)
 {
   uid_t myuid;
   struct passwd *pw;
   struct spwd *sp;
-  char *name = NULL;
-  char *pass = NULL, *encrypted = NULL, *newp = NULL;
-  char *orig = (char *)"";
-  char salt[MAX_SALT_LEN];
+  char *name = NULL, *pass = NULL, *encrypted = NULL, *newp = NULL,
+       *orig = (char *)"", salt[MAX_SALT_LEN];
   int ret = -1;
 
   myuid = getuid();
-  if ((myuid != 0) && (toys.optflags & (FLAG_l | FLAG_u | FLAG_d)))
+  if ((myuid) && (toys.optflags & (FLAG_l | FLAG_u | FLAG_d)))
     error_exit("You need to be root to do these actions\n");
 
   pw = getpwuid(myuid);
-
   if (!pw) error_exit("Unknown uid '%u'",myuid);
 
   if (toys.optargs[0]) name = toys.optargs[0];
@@ -176,23 +115,28 @@ void passwd_main(void)
   pw = getpwnam(name);
   if (!pw) error_exit("Unknown user '%s'",name);
 
-  if (myuid != 0 && (myuid != pw->pw_uid))
+  if (myuid && (myuid != pw->pw_uid))
     error_exit("You need to be root to change '%s' password\n", name);
 
   pass = pw->pw_passwd;
   if (pw->pw_passwd[0] == 'x') {
-    /*get shadow passwd */
+    //get shadow passwd
     sp = getspnam(name);
     if (sp) pass = sp->sp_pwdp;
   }
 
 
   if (!(toys.optflags & (FLAG_l | FLAG_u | FLAG_d))) {
+    
+    if (!(toys.optflags & FLAG_a)) TT.algo = "des";
+    if (get_salt(salt, TT.algo) == -1)
+      error_exit("Error: Unkown encryption algorithm\n");
+
     printf("Changing password for %s\n",name);
-    if (pass[0] == '!')
+    if (myuid && pass[0] == '!')
       error_exit("Can't change, password is locked for %s",name);
-    if (myuid != 0) {
-      /*Validate user */
+    if (myuid) {
+      //Validate user 
 
       if (read_password(toybuf, sizeof(toybuf), "Origial password:")) {
         if (!toys.optargs[0]) free(name);
@@ -204,7 +148,7 @@ void passwd_main(void)
 
     orig = xstrdup(orig);
 
-    /*Get new password */
+    // Get new password
     newp = new_password(orig, name);
     if (!newp) {
       free(orig);
@@ -212,31 +156,24 @@ void passwd_main(void)
       return; //new password is not set well.
     }
 
-    /*Encrypt the passwd */
-    if (!(toys.optflags & FLAG_a)) TT.algo = "des";
-
-    if (get_salt(salt)) error_exit("Error: Unkown encryption algorithm\n");
-
     encrypted = crypt(newp, salt);
     free(newp);
     free(orig);
   } else if (toys.optflags & FLAG_l) {
-    if (pass[0] == '!')
-      error_exit("password is already locked for %s",name);
+    if (pass[0] == '!') error_exit("password is already locked for %s",name);
     printf("Locking password for %s\n",name);
     encrypted = xmsprintf("!%s",pass);
   } else if (toys.optflags & FLAG_u) {
-    if (pass[0] != '!')
-      error_exit("password is already unlocked for %s",name);
+    if (pass[0] != '!') error_exit("password is already unlocked for %s",name);
 
     printf("Unlocking password for %s\n",name);
     encrypted = xstrdup(&pass[1]);
   } else if (toys.optflags & FLAG_d) {
     printf("Deleting password for %s\n",name);
-    encrypted = (char*)xzalloc(sizeof(char)*2); //1 = "", 2 = '\0'
+    encrypted = xstrdup(""); //1 = "", 2 = '\0'
   }
 
-  /*Update the passwd */
+  // Update the passwd
   if (pw->pw_passwd[0] == 'x')
     ret = update_password("/etc/shadow", name, encrypted);
   else ret = update_password("/etc/passwd", name, encrypted);
-- 
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