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adduser: safe username passing to passwd/addgroup

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passwd: support creating SHA passwords
random code shrink

function                                             old     new   delta
crypt_make_pw_salt                                     -      87     +87
adduser_main                                         883     904     +21
...
crypt_make_salt                                       99      89     -10
chpasswd_main                                        329     312     -17
packed_usage                                       28731   28691     -40
passwd_main                                         1070    1000     -70
cryptpw_main                                         310     224     -86
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/12 up/down: 154/-288)        Total: -134 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2011-05-13 03:19:01 +02:00
parent 0806e401d6
commit 12a432715f
7 changed files with 88 additions and 77 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
include/libbb.h
View File

@ -1259,14 +1259,19 @@ extern int correct_password(const struct passwd *pw) FAST_FUNC;
#endif #endif
extern char *pw_encrypt(const char *clear, const char *salt, int cleanup) FAST_FUNC; extern char *pw_encrypt(const char *clear, const char *salt, int cleanup) FAST_FUNC;
extern int obscure(const char *old, const char *newval, const struct passwd *pwdp) FAST_FUNC; extern int obscure(const char *old, const char *newval, const struct passwd *pwdp) FAST_FUNC;
/* rnd is additional random input. New one is returned. /*
* rnd is additional random input. New one is returned.
* Useful if you call crypt_make_salt many times in a row: * Useful if you call crypt_make_salt many times in a row:
* rnd = crypt_make_salt(buf1, 4, 0); * rnd = crypt_make_salt(buf1, 4, 0);
* rnd = crypt_make_salt(buf2, 4, rnd); * rnd = crypt_make_salt(buf2, 4, rnd);
* rnd = crypt_make_salt(buf3, 4, rnd); * rnd = crypt_make_salt(buf3, 4, rnd);
* (otherwise we risk having same salt generated) * (otherwise we risk having same salt generated)
*/ */
extern int crypt_make_salt(char *p, int cnt, int rnd) FAST_FUNC; extern int crypt_make_salt(char *p, int cnt /*, int rnd*/) FAST_FUNC;
/* "$N$" + sha_salt_16_bytes + NUL */
#define MAX_PW_SALT_LEN (3 + 16 + 1)
extern char* crypt_make_pw_salt(char p[MAX_PW_SALT_LEN], const char *algo) FAST_FUNC;
/* Returns number of lines changed, or -1 on error */ /* Returns number of lines changed, or -1 on error */
#if !(ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP) #if !(ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP)

25
libbb/pw_encrypt.c
View File

@ -27,9 +27,10 @@ static int i64c(int i)
return ('a' - 38 + i); return ('a' - 38 + i);
} }
int FAST_FUNC crypt_make_salt(char *p, int cnt, int x) int FAST_FUNC crypt_make_salt(char *p, int cnt /*, int x */)
{ {
x += getpid() + time(NULL); /* was: x += ... */
int x = getpid() + monotonic_us();
do { do {
/* x = (x*1664525 + 1013904223) % 2^32 generator is lame /* x = (x*1664525 + 1013904223) % 2^32 generator is lame
* (low-order bit is not "random", etc...), * (low-order bit is not "random", etc...),
@ -47,6 +48,26 @@ int FAST_FUNC crypt_make_salt(char *p, int cnt, int x)
return x; return x;
} }
char* FAST_FUNC crypt_make_pw_salt(char salt[MAX_PW_SALT_LEN], const char *algo)
{
int len = 2/2;
char *salt_ptr = salt;
if (algo[0] != 'd') { /* not des */
len = 8/2; /* so far assuming md5 */
*salt_ptr++ = '$';
*salt_ptr++ = '1';
*salt_ptr++ = '$';
#if !ENABLE_USE_BB_CRYPT || ENABLE_USE_BB_CRYPT_SHA
if (algo[0] == 's') { /* sha */
salt[1] = '5' + (strcmp(algo, "sha512") == 0);
len = 16/2;
}
#endif
}
crypt_make_salt(salt_ptr, len);
return salt_ptr;
}
#if ENABLE_USE_BB_CRYPT #if ENABLE_USE_BB_CRYPT
static char* static char*

16
loginutils/adduser.c
View File

@ -82,21 +82,23 @@ static void passwd_study(struct passwd *p)
static void addgroup_wrapper(struct passwd *p, const char *group_name) static void addgroup_wrapper(struct passwd *p, const char *group_name)
{ {
char *argv[5]; char *argv[6];
argv[0] = (char*)"addgroup"; argv[0] = (char*)"addgroup";
if (group_name) { if (group_name) {
/* Add user to existing group */ /* Add user to existing group */
argv[1] = p->pw_name; argv[1] = (char*)"--";
argv[2] = (char*)group_name; argv[2] = p->pw_name;
argv[3] = NULL; argv[3] = (char*)group_name;
argv[4] = NULL;
} else { } else {
/* Add user to his own group with the first free gid found in passwd_study */ /* Add user to his own group with the first free gid found in passwd_study */
//TODO: to be compatible with external addgroup programs we should use --gid instead... //TODO: to be compatible with external addgroup programs we should use --gid instead...
argv[1] = (char*)"-g"; argv[1] = (char*)"-g";
argv[2] = utoa(p->pw_gid); argv[2] = utoa(p->pw_gid);
argv[3] = p->pw_name; argv[3] = (char*)"--";
argv[4] = NULL; argv[4] = p->pw_name;
argv[5] = NULL;
} }
spawn_and_wait(argv); spawn_and_wait(argv);
@ -106,7 +108,7 @@ static void passwd_wrapper(const char *login_name) NORETURN;
static void passwd_wrapper(const char *login_name) static void passwd_wrapper(const char *login_name)
{ {
BB_EXECLP("passwd", "passwd", login_name, NULL); BB_EXECLP("passwd", "passwd", "--", login_name, NULL);
bb_error_msg_and_die("can't execute passwd, you must set password manually"); bb_error_msg_and_die("can't execute passwd, you must set password manually");
} }

11
loginutils/chpasswd.c
View File

@ -37,9 +37,8 @@ int chpasswd_main(int argc UNUSED_PARAM, char **argv)
char *name, *pass; char *name, *pass;
char salt[sizeof("$N$XXXXXXXX")]; char salt[sizeof("$N$XXXXXXXX")];
int opt, rc; int opt, rc;
int rnd = rnd; /* we *want* it to be non-initialized! */
if (getuid()) if (getuid() != 0)
bb_error_msg_and_die(bb_msg_perm_denied_are_you_root); bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
opt_complementary = "m--e:e--m"; opt_complementary = "m--e:e--m";
@ -55,10 +54,12 @@ int chpasswd_main(int argc UNUSED_PARAM, char **argv)
xuname2uid(name); /* dies if there is no such user */ xuname2uid(name); /* dies if there is no such user */
if (!(opt & OPT_ENC)) { if (!(opt & OPT_ENC)) {
rnd = crypt_make_salt(salt, 1, rnd); crypt_make_salt(salt, 1);
if (opt & OPT_MD5) { if (opt & OPT_MD5) {
strcpy(salt, "$1$"); salt[0] = '$';
rnd = crypt_make_salt(salt + 3, 4, rnd); salt[1] = '1';
salt[2] = '$';
crypt_make_salt(salt + 3, 4);
} }
pass = pw_encrypt(pass, salt, 0); pass = pw_encrypt(pass, salt, 0);
} }

27
loginutils/cryptpw.c
View File

@ -19,7 +19,7 @@
//usage: IF_LONG_OPTS( //usage: IF_LONG_OPTS(
//usage: "\n -P,--password-fd=N Read password from fd N" //usage: "\n -P,--password-fd=N Read password from fd N"
/* //usage: "\n -s,--stdin Use stdin; like -P0" */ /* //usage: "\n -s,--stdin Use stdin; like -P0" */
//usage: "\n -m,--method=TYPE Encryption method TYPE" //usage: "\n -m,--method=TYPE Encryption method"
//usage: "\n -S,--salt=SALT" //usage: "\n -S,--salt=SALT"
//usage: ) //usage: )
//usage: IF_NOT_LONG_OPTS( //usage: IF_NOT_LONG_OPTS(
@ -39,7 +39,7 @@
//usage: IF_LONG_OPTS( //usage: IF_LONG_OPTS(
//usage: "\n -P,--password-fd=N Read password from fd N" //usage: "\n -P,--password-fd=N Read password from fd N"
/* //usage: "\n -s,--stdin Use stdin; like -P0" */ /* //usage: "\n -s,--stdin Use stdin; like -P0" */
//usage: "\n -m,--method=TYPE Encryption method TYPE" //usage: "\n -m,--method=TYPE Encryption method"
//usage: "\n -S,--salt=SALT" //usage: "\n -S,--salt=SALT"
//usage: ) //usage: )
//usage: IF_NOT_LONG_OPTS( //usage: IF_NOT_LONG_OPTS(
@ -92,11 +92,9 @@ to cryptpw. -a option (alias for -m) came from cryptpw.
int cryptpw_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int cryptpw_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int cryptpw_main(int argc UNUSED_PARAM, char **argv) int cryptpw_main(int argc UNUSED_PARAM, char **argv)
{ {
/* $N$ + sha_salt_16_bytes + NUL */ char salt[MAX_PW_SALT_LEN];
char salt[3 + 16 + 1];
char *salt_ptr; char *salt_ptr;
const char *opt_m, *opt_S; const char *opt_m, *opt_S;
int len;
int fd; int fd;
#if ENABLE_LONG_OPTS #if ENABLE_LONG_OPTS
@ -121,24 +119,9 @@ int cryptpw_main(int argc UNUSED_PARAM, char **argv)
if (argv[0] && !opt_S) if (argv[0] && !opt_S)
opt_S = argv[1]; opt_S = argv[1];
len = 2/2; salt_ptr = crypt_make_pw_salt(salt, opt_m);
salt_ptr = salt;
if (opt_m[0] != 'd') { /* not des */
len = 8/2; /* so far assuming md5 */
*salt_ptr++ = '$';
*salt_ptr++ = '1';
*salt_ptr++ = '$';
#if !ENABLE_USE_BB_CRYPT || ENABLE_USE_BB_CRYPT_SHA
if (opt_m[0] == 's') { /* sha */
salt[1] = '5' + (strcmp(opt_m, "sha512") == 0);
len = 16/2;
}
#endif
}
if (opt_S) if (opt_S)
safe_strncpy(salt_ptr, opt_S, sizeof(salt) - 3); safe_strncpy(salt_ptr, opt_S, sizeof(salt) - (sizeof("$N$")-1));
else
crypt_make_salt(salt_ptr, len, 0);
xmove_fd(fd, STDIN_FILENO); xmove_fd(fd, STDIN_FILENO);

75
loginutils/passwd.c
View File

@ -9,7 +9,7 @@
//usage: "Change USER's password. If no USER is specified,\n" //usage: "Change USER's password. If no USER is specified,\n"
//usage: "changes the password for the current user.\n" //usage: "changes the password for the current user.\n"
//usage: "\nOptions:" //usage: "\nOptions:"
//usage: "\n -a ALG Algorithm to use for password (des, md5)" /* ", sha1)" */ //usage: "\n -a ALG Encryption method"
//usage: "\n -d Delete password for the account" //usage: "\n -d Delete password for the account"
//usage: "\n -l Lock (disable) account" //usage: "\n -l Lock (disable) account"
//usage: "\n -u Unlock (re-enable) account" //usage: "\n -u Unlock (re-enable) account"
@ -22,15 +22,15 @@ static void nuke_str(char *str)
if (str) memset(str, 0, strlen(str)); if (str) memset(str, 0, strlen(str));
} }
static char* new_password(const struct passwd *pw, uid_t myuid, int algo) static char* new_password(const struct passwd *pw, uid_t myuid, const char *algo)
{ {
char salt[sizeof("$N$XXXXXXXX")]; /* "$N$XXXXXXXX" or "XX" */ char salt[MAX_PW_SALT_LEN];
char *orig = (char*)""; char *orig = (char*)"";
char *newp = NULL; char *newp = NULL;
char *cp = NULL; char *cp = NULL;
char *ret = NULL; /* failure so far */ char *ret = NULL; /* failure so far */
if (myuid && pw->pw_passwd[0]) { if (myuid != 0 && pw->pw_passwd[0]) {
char *encrypted; char *encrypted;
orig = bb_ask_stdin("Old password: "); /* returns ptr to static */ orig = bb_ask_stdin("Old password: "); /* returns ptr to static */
@ -38,13 +38,13 @@ static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
goto err_ret; goto err_ret;
encrypted = pw_encrypt(orig, pw->pw_passwd, 1); /* returns malloced str */ encrypted = pw_encrypt(orig, pw->pw_passwd, 1); /* returns malloced str */
if (strcmp(encrypted, pw->pw_passwd) != 0) { if (strcmp(encrypted, pw->pw_passwd) != 0) {
syslog(LOG_WARNING, "incorrect password for %s", syslog(LOG_WARNING, "incorrect password for %s", pw->pw_name);
pw->pw_name);
bb_do_delay(LOGIN_FAIL_DELAY); bb_do_delay(LOGIN_FAIL_DELAY);
puts("Incorrect password"); puts("Incorrect password");
goto err_ret; goto err_ret;
} }
if (ENABLE_FEATURE_CLEAN_UP) free(encrypted); if (ENABLE_FEATURE_CLEAN_UP)
free(encrypted);
} }
orig = xstrdup(orig); /* or else bb_ask_stdin() will destroy it */ orig = xstrdup(orig); /* or else bb_ask_stdin() will destroy it */
newp = bb_ask_stdin("New password: "); /* returns ptr to static */ newp = bb_ask_stdin("New password: "); /* returns ptr to static */
@ -52,22 +52,22 @@ static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
goto err_ret; goto err_ret;
newp = xstrdup(newp); /* we are going to bb_ask_stdin() again, so save it */ newp = xstrdup(newp); /* we are going to bb_ask_stdin() again, so save it */
if (ENABLE_FEATURE_PASSWD_WEAK_CHECK if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
&& obscure(orig, newp, pw) && myuid) && obscure(orig, newp, pw)
&& myuid != 0
) {
goto err_ret; /* non-root is not allowed to have weak passwd */ goto err_ret; /* non-root is not allowed to have weak passwd */
}
cp = bb_ask_stdin("Retype password: "); cp = bb_ask_stdin("Retype password: ");
if (!cp) if (!cp)
goto err_ret; goto err_ret;
if (strcmp(cp, newp)) { if (strcmp(cp, newp) != 0) {
puts("Passwords don't match"); puts("Passwords don't match");
goto err_ret; goto err_ret;
} }
crypt_make_salt(salt, 1, 0); /* des */ crypt_make_pw_salt(salt, algo);
if (algo) { /* MD5 */
strcpy(salt, "$1$");
crypt_make_salt(salt + 3, 4, 0);
}
/* pw_encrypt returns malloced str */ /* pw_encrypt returns malloced str */
ret = pw_encrypt(newp, salt, 1); ret = pw_encrypt(newp, salt, 1);
/* whee, success! */ /* whee, success! */
@ -75,8 +75,10 @@ static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
err_ret: err_ret:
nuke_str(orig); nuke_str(orig);
if (ENABLE_FEATURE_CLEAN_UP) free(orig); if (ENABLE_FEATURE_CLEAN_UP) free(orig);
nuke_str(newp); nuke_str(newp);
if (ENABLE_FEATURE_CLEAN_UP) free(newp); if (ENABLE_FEATURE_CLEAN_UP) free(newp);
nuke_str(cp); nuke_str(cp);
return ret; return ret;
} }
@ -85,17 +87,15 @@ int passwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int passwd_main(int argc UNUSED_PARAM, char **argv) int passwd_main(int argc UNUSED_PARAM, char **argv)
{ {
enum { enum {
OPT_algo = 0x1, /* -a - password algorithm */ OPT_algo = (1 << 0), /* -a - password algorithm */
OPT_lock = 0x2, /* -l - lock account */ OPT_lock = (1 << 1), /* -l - lock account */
OPT_unlock = 0x4, /* -u - unlock account */ OPT_unlock = (1 << 2), /* -u - unlock account */
OPT_delete = 0x8, /* -d - delete password */ OPT_delete = (1 << 3), /* -d - delete password */
OPT_lud = 0xe, OPT_lud = OPT_lock | OPT_unlock | OPT_delete,
STATE_ALGO_md5 = 0x10,
//STATE_ALGO_des = 0x20, not needed yet
}; };
unsigned opt; unsigned opt;
int rc; int rc;
const char *opt_a = ""; const char *opt_a = "d"; /* des */
const char *filename; const char *filename;
char *myname; char *myname;
char *name; char *name;
@ -116,13 +116,9 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
//argc -= optind; //argc -= optind;
argv += optind; argv += optind;
if (strcasecmp(opt_a, "des") != 0) /* -a */
opt |= STATE_ALGO_md5;
//else
// opt |= STATE_ALGO_des;
myuid = getuid(); myuid = getuid();
/* -l, -u, -d require root priv and username argument */ /* -l, -u, -d require root priv and username argument */
if ((opt & OPT_lud) && (myuid || !argv[0])) if ((opt & OPT_lud) && (myuid != 0 || !argv[0]))
bb_show_usage(); bb_show_usage();
/* Will complain and die if username not found */ /* Will complain and die if username not found */
@ -130,7 +126,7 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
name = argv[0] ? argv[0] : myname; name = argv[0] ? argv[0] : myname;
pw = xgetpwnam(name); pw = xgetpwnam(name);
if (myuid && pw->pw_uid != myuid) { if (myuid != 0 && pw->pw_uid != myuid) {
/* LOGMODE_BOTH */ /* LOGMODE_BOTH */
bb_error_msg_and_die("%s can't change password for %s", myname, name); bb_error_msg_and_die("%s can't change password for %s", myname, name);
} }
@ -164,27 +160,29 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
newp = NULL; newp = NULL;
c = pw->pw_passwd[0] - '!'; c = pw->pw_passwd[0] - '!';
if (!(opt & OPT_lud)) { if (!(opt & OPT_lud)) {
if (myuid && !c) { /* passwd starts with '!' */ if (myuid != 0 && !c) { /* passwd starts with '!' */
/* LOGMODE_BOTH */ /* LOGMODE_BOTH */
bb_error_msg_and_die("can't change " bb_error_msg_and_die("can't change "
"locked password for %s", name); "locked password for %s", name);
} }
printf("Changing password for %s\n", name); printf("Changing password for %s\n", name);
newp = new_password(pw, myuid, opt & STATE_ALGO_md5); newp = new_password(pw, myuid, opt_a);
if (!newp) { if (!newp) {
logmode = LOGMODE_STDIO; logmode = LOGMODE_STDIO;
bb_error_msg_and_die("password for %s is unchanged", name); bb_error_msg_and_die("password for %s is unchanged", name);
} }
} else if (opt & OPT_lock) { } else if (opt & OPT_lock) {
if (!c) goto skip; /* passwd starts with '!' */ if (!c)
goto skip; /* passwd starts with '!' */
newp = xasprintf("!%s", pw->pw_passwd); newp = xasprintf("!%s", pw->pw_passwd);
} else if (opt & OPT_unlock) { } else if (opt & OPT_unlock) {
if (c) goto skip; /* not '!' */ if (c)
goto skip; /* not '!' */
/* pw->pw_passwd points to static storage, /* pw->pw_passwd points to static storage,
* strdup'ing to avoid nasty surprizes */ * strdup'ing to avoid nasty surprizes */
newp = xstrdup(&pw->pw_passwd[1]); newp = xstrdup(&pw->pw_passwd[1]);
} else if (opt & OPT_delete) { } else if (opt & OPT_delete) {
newp = (char*)""; //xstrdup(""); newp = (char*)"";
} }
rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000; rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
@ -202,7 +200,7 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
rc = update_passwd(bb_path_shadow_file, name, newp, NULL); rc = update_passwd(bb_path_shadow_file, name, newp, NULL);
if (rc > 0) if (rc > 0)
/* password in /etc/shadow was updated */ /* password in /etc/shadow was updated */
newp = (char*) "x"; //xstrdup("x"); newp = (char*) "x";
if (rc >= 0) if (rc >= 0)
/* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */ /* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */
#endif #endif
@ -212,16 +210,17 @@ int passwd_main(int argc UNUSED_PARAM, char **argv)
} }
/* LOGMODE_BOTH */ /* LOGMODE_BOTH */
if (rc < 0) if (rc < 0)
bb_error_msg_and_die("can't update password file %s", bb_error_msg_and_die("can't update password file %s", filename);
filename);
bb_info_msg("Password for %s changed by %s", name, myname); bb_info_msg("Password for %s changed by %s", name, myname);
//if (ENABLE_FEATURE_CLEAN_UP) free(newp); /*if (ENABLE_FEATURE_CLEAN_UP) free(newp); - can't, it may be non-malloced */
skip: skip:
if (!newp) { if (!newp) {
bb_error_msg_and_die("password for %s is already %slocked", bb_error_msg_and_die("password for %s is already %slocked",
name, (opt & OPT_unlock) ? "un" : ""); name, (opt & OPT_unlock) ? "un" : "");
} }
if (ENABLE_FEATURE_CLEAN_UP) free(myname);
if (ENABLE_FEATURE_CLEAN_UP)
free(myname);
return 0; return 0;
} }

2
networking/httpd.c
View File

@ -2424,7 +2424,7 @@ int httpd_main(int argc UNUSED_PARAM, char **argv)
salt[0] = '$'; salt[0] = '$';
salt[1] = '1'; salt[1] = '1';
salt[2] = '$'; salt[2] = '$';
crypt_make_salt(salt + 3, 4, 0); crypt_make_salt(salt + 3, 4);
puts(pw_encrypt(pass, salt, 1)); puts(pw_encrypt(pass, salt, 1));
return 0; return 0;
} }