From feac9b607dc68ea63992a46b3b8361f00f663cdc Mon Sep 17 00:00:00 2001 From: Morten Kvistgaard Date: Tue, 5 Aug 2014 21:57:18 +0200 Subject: ftpd: add optional support for authentication function old new delta cmdio_get_cmd_and_arg - 237 +237 get_passwd - 97 +97 check_password - 82 +82 ftpd_main 2297 2178 -119 ask_and_check_password_extended 206 84 -122 ------------------------------------------------------------------------------ (add/remove: 3/0 grow/shrink: 0/2 up/down: 416/-241) Total: 175 bytes Signed-off-by: Morten Kvistgaard Signed-off-by: Denys Vlasenko --- libbb/correct_password.c | 96 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 67 insertions(+), 29 deletions(-) (limited to 'libbb/correct_password.c') diff --git a/libbb/correct_password.c b/libbb/correct_password.c index acadf3914..513c93028 100644 --- a/libbb/correct_password.c +++ b/libbb/correct_password.c @@ -30,6 +30,63 @@ #include "libbb.h" +#define SHADOW_BUFSIZE 256 + +/* Retrieve encrypted password string for pw. + * If pw == NULL, return a string which fails password check against any + * password. + */ +#if !ENABLE_FEATURE_SHADOWPASSWDS +#define get_passwd(pw, buffer) get_passwd(pw) +#endif +static const char *get_passwd(const struct passwd *pw, char buffer[SHADOW_BUFSIZE]) +{ + const char *pass; + + if (!pw) + return "aa"; /* "aa" will never match */ + + pass = pw->pw_passwd; +#if ENABLE_FEATURE_SHADOWPASSWDS + /* Using _r function to avoid pulling in static buffers */ + if ((pass[0] == 'x' || pass[0] == '*') && !pass[1]) { + struct spwd spw; + int r; + /* getspnam_r may return 0 yet set result to NULL. + * At least glibc 2.4 does this. Be extra paranoid here. */ + struct spwd *result = NULL; + r = getspnam_r(pw->pw_name, &spw, buffer, SHADOW_BUFSIZE, &result); + pass = (r || !result) ? "aa" : result->sp_pwdp; + } +#endif + return pass; +} + +/* + * Return 1 if PW has an empty password. + * Return 1 if the user gives the correct password for entry PW, + * 0 if not. + * NULL pw means "just fake it for login with bad username" + */ +int FAST_FUNC check_password(const struct passwd *pw, const char *plaintext) +{ + IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];) + char *encrypted; + const char *pw_pass; + int r; + + pw_pass = get_passwd(pw, buffer); + if (!pw_pass[0]) { /* empty password field? */ + return 1; + } + + encrypted = pw_encrypt(plaintext, /*salt:*/ pw_pass, 1); + r = (strcmp(encrypted, pw_pass) == 0); + free(encrypted); + return r; +} + + /* Ask the user for a password. * Return 1 without asking if PW has an empty password. * Return -1 on EOF, error while reading input, or timeout. @@ -41,42 +98,23 @@ int FAST_FUNC ask_and_check_password_extended(const struct passwd *pw, int timeout, const char *prompt) { - char *unencrypted, *encrypted; - const char *correct; + IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];) + char *plaintext; + const char *pw_pass; int r; - /* fake salt. crypt() can choke otherwise. */ - correct = "aa"; - if (!pw) { - /* "aa" will never match */ - goto fake_it; - } - correct = pw->pw_passwd; -#if ENABLE_FEATURE_SHADOWPASSWDS - /* Using _r function to avoid pulling in static buffers */ - if ((correct[0] == 'x' || correct[0] == '*') && !correct[1]) { - struct spwd spw; - char buffer[256]; - /* getspnam_r may return 0 yet set result to NULL. - * At least glibc 2.4 does this. Be extra paranoid here. */ - struct spwd *result = NULL; - r = getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result); - correct = (r || !result) ? "aa" : result->sp_pwdp; - } -#endif - if (!correct[0]) /* empty password field? */ + pw_pass = get_passwd(pw, buffer); + if (!pw_pass[0]) /* empty password field? */ return 1; - fake_it: - unencrypted = bb_ask(STDIN_FILENO, timeout, prompt); - if (!unencrypted) { + plaintext = bb_ask(STDIN_FILENO, timeout, prompt); + if (!plaintext) { /* EOF (such as ^D) or error (such as ^C) or timeout */ return -1; } - encrypted = pw_encrypt(unencrypted, correct, 1); - r = (strcmp(encrypted, correct) == 0); - free(encrypted); - nuke_str(unencrypted); + + r = check_password(pw, plaintext); + nuke_str(plaintext); return r; } -- cgit v1.2.3