lighttpd1.4/src/http_auth.c

#include "server.h"
#include "log.h"
#include "http_auth.h"
#include "inet_ntop_cache.h"
#include "stream.h"

#ifdef HAVE_CRYPT_H
# include <crypt.h>
#elif defined(__linux__)
/* linux needs _XOPEN_SOURCE */
# define _XOPEN_SOURCE
#endif

#if defined(HAVE_LIBCRYPT) && !defined(HAVE_CRYPT)
/* always assume crypt() is present if we have -lcrypt */
# define HAVE_CRYPT
#endif

#include <sys/types.h>
#include <sys/stat.h>

#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <unistd.h>
#include <ctype.h>

#include "md5.h"

#ifdef USE_OPENSSL
#include <openssl/sha.h>
#endif

#define HASHLEN 16
#define HASHHEXLEN 32
typedef unsigned char HASH[HASHLEN];
typedef char HASHHEX[HASHHEXLEN+1];

static void CvtHex(const HASH Bin, char Hex[33]) {
	li_tohex(Hex, (const char*) Bin, 16);
}

/**
 * the $apr1$ handling is taken from apache 1.3.x
 */

/*
 * The apr_md5_encode() routine uses much code obtained from the FreeBSD 3.0
 * MD5 crypt() function, which is licenced as follows:
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
 * ----------------------------------------------------------------------------
 */

handler_t auth_ldap_init(server *srv, mod_auth_plugin_config *s);

static const char base64_pad = '=';

/* "A-Z a-z 0-9 + /" maps to 0-63 */
static const short base64_reverse_table[256] = {
/*	 0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x00 - 0x0F */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x10 - 0x1F */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /* 0x20 - 0x2F */
	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, /* 0x30 - 0x3F */
	-1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, /* 0x40 - 0x4F */
	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 0x50 - 0x5F */
	-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 - 0x6F */
	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 - 0x7F */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x80 - 0x8F */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x90 - 0x9F */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xA0 - 0xAF */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xB0 - 0xBF */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xC0 - 0xCF */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xD0 - 0xDF */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xE0 - 0xEF */
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xF0 - 0xFF */
};


static unsigned char * base64_decode(buffer *out, const char *in) {
	unsigned char *result;
	unsigned int j = 0; /* current output character (position) that is decoded. can contain partial result */
	unsigned int group = 0; /* how many base64 digits in the current group were decoded already. each group has up to 4 digits */
	size_t i;

	size_t in_len = strlen(in);

	result = (unsigned char *) buffer_string_prepare_copy(out, in_len);

	/* run through the whole string, converting as we go */
	for (i = 0; i < in_len; i++) {
		unsigned char c = (unsigned char) in[i];
		short ch;

		if (c == '\0') break;

		if (c == base64_pad) {
			/* pad character can only come after 2 base64 digits in a group */
			if (group < 2) return NULL;
			break;
		}

		ch = base64_reverse_table[c];
		if (ch < 0) continue; /* skip invalid characters */

		switch(group) {
		case 0:
			result[j] = ch << 2;
			group = 1;
			break;
		case 1:
			result[j++] |= ch >> 4;
			result[j] = (ch & 0x0f) << 4;
			group = 2;
			break;
		case 2:
			result[j++] |= ch >>2;
			result[j] = (ch & 0x03) << 6;
			group = 3;
			break;
		case 3:
			result[j++] |= ch;
			group = 0;
			break;
		}
	}

	switch(group) {
	case 0:
		/* ended on boundary */
		break;
	case 1:
		/* need at least 2 base64 digits per group */
		return NULL;
	case 2:
		/* have 2 base64 digits in last group => one real octect, two zeroes padded */
	case 3:
		/* have 3 base64 digits in last group => two real octects, one zero padded */

		/* for both cases the current index already is on the first zero padded octet
		 * - check it really is zero (overlapping bits) */
		if (0 != result[j]) return NULL;
		break;
	}

	buffer_commit(out, j);

	return result;
}

static int http_auth_get_password(server *srv, mod_auth_plugin_data *p, buffer *username, buffer *realm, buffer *password) {
	int ret = -1;

	if (buffer_is_empty(username) || buffer_is_empty(realm)) return -1;

	if (p->conf.auth_backend == AUTH_BACKEND_HTDIGEST) {
		stream f;
		char * f_line;

		if (buffer_string_is_empty(p->conf.auth_htdigest_userfile)) return -1;

		if (0 != stream_open(&f, p->conf.auth_htdigest_userfile)) {
			log_error_write(srv, __FILE__, __LINE__, "sbss", "opening digest-userfile", p->conf.auth_htdigest_userfile, "failed:", strerror(errno));

			return -1;
		}

		f_line = f.start;

		while (f_line - f.start != f.size) {
			char *f_user, *f_pwd, *e, *f_realm;
			size_t u_len, pwd_len, r_len;

			f_user = f_line;

			/*
			 * htdigest format
			 *
			 * user:realm:md5(user:realm:password)
			 */

			if (NULL == (f_realm = memchr(f_user, ':', f.size - (f_user - f.start) ))) {
				log_error_write(srv, __FILE__, __LINE__, "sbs",
						"parsed error in", p->conf.auth_htdigest_userfile,
						"expected 'username:realm:hashed password'");

				stream_close(&f);

				return -1;
			}

			if (NULL == (f_pwd = memchr(f_realm + 1, ':', f.size - (f_realm + 1 - f.start)))) {
				log_error_write(srv, __FILE__, __LINE__, "sbs",
						"parsed error in", p->conf.auth_plain_userfile,
						"expected 'username:realm:hashed password'");

				stream_close(&f);

				return -1;
			}

			/* get pointers to the fields */
			u_len = f_realm - f_user;
			f_realm++;
			r_len = f_pwd - f_realm;
			f_pwd++;

			if (NULL != (e = memchr(f_pwd, '\n', f.size - (f_pwd - f.start)))) {
				pwd_len = e - f_pwd;
			} else {
				pwd_len = f.size - (f_pwd - f.start);
			}

			if (buffer_string_length(username) == u_len &&
			    (buffer_string_length(realm) == r_len) &&
			    (0 == strncmp(username->ptr, f_user, u_len)) &&
			    (0 == strncmp(realm->ptr, f_realm, r_len))) {
				/* found */

				buffer_copy_string_len(password, f_pwd, pwd_len);

				ret = 0;
				break;
			}

			/* EOL */
			if (!e) break;

			f_line = e + 1;
		}

		stream_close(&f);
	} else if (p->conf.auth_backend == AUTH_BACKEND_HTPASSWD ||
		   p->conf.auth_backend == AUTH_BACKEND_PLAIN) {
		stream f;
		char * f_line;
		buffer *auth_fn;

		auth_fn = (p->conf.auth_backend == AUTH_BACKEND_HTPASSWD) ? p->conf.auth_htpasswd_userfile : p->conf.auth_plain_userfile;

		if (buffer_string_is_empty(auth_fn)) return -1;

		if (0 != stream_open(&f, auth_fn)) {
			log_error_write(srv, __FILE__, __LINE__, "sbss",
					"opening plain-userfile", auth_fn, "failed:", strerror(errno));

			return -1;
		}

		f_line = f.start;

		while (f_line - f.start != f.size) {
			char *f_user, *f_pwd, *e;
			size_t u_len, pwd_len;

			f_user = f_line;

			/*
			 * htpasswd format
			 *
			 * user:crypted passwd
			 */

			if (NULL == (f_pwd = memchr(f_user, ':', f.size - (f_user - f.start) ))) {
				log_error_write(srv, __FILE__, __LINE__, "sbs",
						"parsed error in", auth_fn,
						"expected 'username:hashed password'");

				stream_close(&f);

				return -1;
			}

			/* get pointers to the fields */
			u_len = f_pwd - f_user;
			f_pwd++;

			if (NULL != (e = memchr(f_pwd, '\n', f.size - (f_pwd - f.start)))) {
				pwd_len = e - f_pwd;
			} else {
				pwd_len = f.size - (f_pwd - f.start);
			}

			if (buffer_string_length(username) == u_len &&
			    (0 == strncmp(username->ptr, f_user, u_len))) {
				/* found */

				buffer_copy_string_len(password, f_pwd, pwd_len);

				ret = 0;
				break;
			}

			/* EOL */
			if (!e) break;

			f_line = e + 1;
		}

		stream_close(&f);
	} else if (p->conf.auth_backend == AUTH_BACKEND_LDAP) {
		ret = 0;
	} else {
		return -1;
	}

	return ret;
}

int http_auth_match_rules(server *srv, array *req, const char *username, const char *group, const char *host) {
	const char *r = NULL, *rules = NULL;
	int username_len;
	data_string *require;

	UNUSED(group);
	UNUSED(host);

	require = (data_string *)array_get_element(req, "require");

	/* if we get here, the user we got a authed user */
	if (0 == strcmp(require->value->ptr, "valid-user")) {
		return 0;
	}

	/* user=name1|group=name3|host=name4 */

	/* seperate the string by | */
#if 0
	log_error_write(srv, __FILE__, __LINE__, "sb", "rules", require->value);
#endif

	username_len = username ? strlen(username) : 0;

	r = rules = require->value->ptr;

	while (1) {
		const char *eq;
		const char *k, *v, *e;
		int k_len, v_len, r_len;

		e = strchr(r, '|');

		if (e) {
			r_len = e - r;
		} else {
			r_len = strlen(rules) - (r - rules);
		}

		/* from r to r + r_len is a rule */

		if (0 == strncmp(r, "valid-user", r_len)) {
			log_error_write(srv, __FILE__, __LINE__, "sb",
					"parsing the 'require' section in 'auth.require' failed: valid-user cannot be combined with other require rules",
					require->value);
			return -1;
		}

		/* search for = in the rules */
		if (NULL == (eq = strchr(r, '='))) {
			log_error_write(srv, __FILE__, __LINE__, "sb",
					"parsing the 'require' section in 'auth.require' failed: a = is missing",
					require->value);
			return -1;
		}

		/* = out of range */
		if (eq > r + r_len) {
			log_error_write(srv, __FILE__, __LINE__, "sb",
					"parsing the 'require' section in 'auth.require' failed: = out of range",
					require->value);

			return -1;
		}

		/* the part before the = is user|group|host */

		k = r;
		k_len = eq - r;
		v = eq + 1;
		v_len = r_len - k_len - 1;

		if (k_len == 4) {
			if (0 == strncmp(k, "user", k_len)) {
				if (username &&
				    username_len == v_len &&
				    0 == strncmp(username, v, v_len)) {
					return 0;
				}
			} else if (0 == strncmp(k, "host", k_len)) {
				log_error_write(srv, __FILE__, __LINE__, "s", "host ... (not implemented)");
			} else {
				log_error_write(srv, __FILE__, __LINE__, "s", "unknown key");
				return -1;
			}
		} else if (k_len == 5) {
			if (0 == strncmp(k, "group", k_len)) {
				log_error_write(srv, __FILE__, __LINE__, "s", "group ... (not implemented)");
			} else {
				log_error_write(srv, __FILE__, __LINE__, "ss", "unknown key", k);
				return -1;
			}
		} else {
			log_error_write(srv, __FILE__, __LINE__, "s", "unknown  key");
			return -1;
		}

		if (!e) break;
		r = e + 1;
	}

	log_error_write(srv, __FILE__, __LINE__, "s", "nothing matched");

	return -1;
}

#define APR_MD5_DIGESTSIZE 16
#define APR1_ID "$apr1$"

/*
 * The following MD5 password encryption code was largely borrowed from
 * the FreeBSD 3.0 /usr/src/lib/libcrypt/crypt.c file, which is
 * licenced as stated at the top of this file.
 */

static void to64(char *s, unsigned long v, int n)
{
    static const unsigned char itoa64[] =         /* 0 ... 63 => ASCII - 64 */
        "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

    while (--n >= 0) {
        *s++ = itoa64[v&0x3f];
        v >>= 6;
    }
}

static void apr_md5_encode(const char *pw, const char *salt, char *result, size_t nbytes) {
    /*
     * Minimum size is 8 bytes for salt, plus 1 for the trailing NUL,
     * plus 4 for the '$' separators, plus the password hash itself.
     * Let's leave a goodly amount of leeway.
     */

    char passwd[120], *p;
    const char *sp, *ep;
    unsigned char final[APR_MD5_DIGESTSIZE];
    ssize_t sl, pl, i;
    li_MD5_CTX ctx, ctx1;
    unsigned long l;

    /*
     * Refine the salt first.  It's possible we were given an already-hashed
     * string as the salt argument, so extract the actual salt value from it
     * if so.  Otherwise just use the string up to the first '$' as the salt.
     */
    sp = salt;

    /*
     * If it starts with the magic string, then skip that.
     */
    if (!strncmp(sp, APR1_ID, strlen(APR1_ID))) {
        sp += strlen(APR1_ID);
    }

    /*
     * It stops at the first '$' or 8 chars, whichever comes first
     */
    for (ep = sp; (*ep != '\0') && (*ep != '$') && (ep < (sp + 8)); ep++) {
        continue;
    }

    /*
     * Get the length of the true salt
     */
    sl = ep - sp;

    /*
     * 'Time to make the doughnuts..'
     */
    li_MD5_Init(&ctx);

    /*
     * The password first, since that is what is most unknown
     */
    li_MD5_Update(&ctx, pw, strlen(pw));

    /*
     * Then our magic string
     */
    li_MD5_Update(&ctx, APR1_ID, strlen(APR1_ID));

    /*
     * Then the raw salt
     */
    li_MD5_Update(&ctx, sp, sl);

    /*
     * Then just as many characters of the MD5(pw, salt, pw)
     */
    li_MD5_Init(&ctx1);
    li_MD5_Update(&ctx1, pw, strlen(pw));
    li_MD5_Update(&ctx1, sp, sl);
    li_MD5_Update(&ctx1, pw, strlen(pw));
    li_MD5_Final(final, &ctx1);
    for (pl = strlen(pw); pl > 0; pl -= APR_MD5_DIGESTSIZE) {
        li_MD5_Update(&ctx, final,
                      (pl > APR_MD5_DIGESTSIZE) ? APR_MD5_DIGESTSIZE : pl);
    }

    /*
     * Don't leave anything around in vm they could use.
     */
    memset(final, 0, sizeof(final));

    /*
     * Then something really weird...
     */
    for (i = strlen(pw); i != 0; i >>= 1) {
        if (i & 1) {
            li_MD5_Update(&ctx, final, 1);
        }
        else {
            li_MD5_Update(&ctx, pw, 1);
        }
    }

    /*
     * Now make the output string.  We know our limitations, so we
     * can use the string routines without bounds checking.
     */
    strcpy(passwd, APR1_ID);
    strncat(passwd, sp, sl);
    strcat(passwd, "$");

    li_MD5_Final(final, &ctx);

    /*
     * And now, just to make sure things don't run too fast..
     * On a 60 Mhz Pentium this takes 34 msec, so you would
     * need 30 seconds to build a 1000 entry dictionary...
     */
    for (i = 0; i < 1000; i++) {
        li_MD5_Init(&ctx1);
        if (i & 1) {
            li_MD5_Update(&ctx1, pw, strlen(pw));
        }
        else {
            li_MD5_Update(&ctx1, final, APR_MD5_DIGESTSIZE);
        }
        if (i % 3) {
            li_MD5_Update(&ctx1, sp, sl);
        }

        if (i % 7) {
            li_MD5_Update(&ctx1, pw, strlen(pw));
        }

        if (i & 1) {
            li_MD5_Update(&ctx1, final, APR_MD5_DIGESTSIZE);
        }
        else {
            li_MD5_Update(&ctx1, pw, strlen(pw));
        }
        li_MD5_Final(final,&ctx1);
    }

    p = passwd + strlen(passwd);

    l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(p, l, 4); p += 4;
    l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(p, l, 4); p += 4;
    l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(p, l, 4); p += 4;
    l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(p, l, 4); p += 4;
    l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(p, l, 4); p += 4;
    l =                    final[11]                ; to64(p, l, 2); p += 2;
    *p = '\0';

    /*
     * Don't leave anything around in vm they could use.
     */
    memset(final, 0, sizeof(final));

	/* FIXME
	 */
#define apr_cpystrn strncpy
    apr_cpystrn(result, passwd, nbytes - 1);
}

#ifdef USE_OPENSSL
static void apr_sha_encode(const char *pw, char *result, size_t nbytes) {
	static const unsigned char base64_data[65] =
		"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	unsigned char digest[21]; /* multiple of 3 for base64 encoding */
	int i;

	memset(result, 0, nbytes);

	/* need 5 bytes for "{SHA}", 28 for base64 (3 bytes -> 4 bytes) of SHA1 (20 bytes), 1 terminating */
	if (nbytes < 5 + 28 + 1) return;

	SHA1((const unsigned char*) pw, strlen(pw), digest);
	digest[20] = 0;

	strcpy(result, "{SHA}");
	result = result + 5;
	for (i = 0; i < 21; i += 3) {
		unsigned int v = (digest[i] << 16) | (digest[i+1] << 8) | digest[i+2];
		result[3] = base64_data[v & 0x3f]; v >>= 6;
		result[2] = base64_data[v & 0x3f]; v >>= 6;
		result[1] = base64_data[v & 0x3f]; v >>= 6;
		result[0] = base64_data[v & 0x3f];
		result += 4;
	}
	result[-1] = '='; /* last digest character was already end of string, pad it */
	*result = '\0';
}
#endif

/**
 *
 *
 * @param password password-string from the auth-backend
 * @param pw       password-string from the client
 */

static int http_auth_basic_password_compare(server *srv, mod_auth_plugin_data *p, array *req, buffer *username, buffer *realm, buffer *password, const char *pw) {
	UNUSED(srv);
	UNUSED(req);

	if (p->conf.auth_backend == AUTH_BACKEND_HTDIGEST) {
		/*
		 * htdigest format
		 *
		 * user:realm:md5(user:realm:password)
		 */

		li_MD5_CTX Md5Ctx;
		HASH HA1;
		char a1[256];

		li_MD5_Init(&Md5Ctx);
		li_MD5_Update(&Md5Ctx, CONST_BUF_LEN(username));
		li_MD5_Update(&Md5Ctx, CONST_STR_LEN(":"));
		li_MD5_Update(&Md5Ctx, CONST_BUF_LEN(realm));
		li_MD5_Update(&Md5Ctx, CONST_STR_LEN(":"));
		li_MD5_Update(&Md5Ctx, (unsigned char *)pw, strlen(pw));
		li_MD5_Final(HA1, &Md5Ctx);

		CvtHex(HA1, a1);

		if (0 == strcmp(password->ptr, a1)) {
			return 0;
		}
	} else if (p->conf.auth_backend == AUTH_BACKEND_HTPASSWD) {
		char sample[120];
		if (!strncmp(password->ptr, APR1_ID, strlen(APR1_ID))) {
			/*
			 * The hash was created using $apr1$ custom algorithm.
			 */
			apr_md5_encode(pw, password->ptr, sample, sizeof(sample));
			return (strcmp(sample, password->ptr) == 0) ? 0 : 1;
#ifdef USE_OPENSSL
		} else if (0 == strncmp(password->ptr, "{SHA}", 5)) {
			apr_sha_encode(pw, sample, sizeof(sample));
			return (strcmp(sample, password->ptr) == 0) ? 0 : 1;
#endif
		} else {
#if defined(HAVE_CRYPT_R) || defined(HAVE_CRYPT)
			char *crypted;
#if defined(HAVE_CRYPT_R)
			struct crypt_data crypt_tmp_data;
			crypt_tmp_data.initialized = 0;
#endif

			/* a simple DES password is 2 + 11 characters. everything else should be longer. */