Repoll immediately if a protocol error happens during the authentication - fetchmail - [fork] set imap idle timeout to 600s, some servers don't follow rfc recommendations

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author	Matthias Andree <matthias.andree@gmx.de>	2007-03-02 00:36:00 +0000
committer	Matthias Andree <matthias.andree@gmx.de>	2007-03-02 00:36:00 +0000
commit	55d0b2fbac078f4295069f23a42567118b8907e0 (patch)
tree	ab9ed1a2f112e7dfb83acdfb94ce2c7831244b37 /cram.c
parent	293c3ad71c5964d77afd3dcd41f5bd0cc1c7b5d7 (diff)
download	fetchmail-55d0b2fbac078f4295069f23a42567118b8907e0.tar.gz fetchmail-55d0b2fbac078f4295069f23a42567118b8907e0.tar.bz2 fetchmail-55d0b2fbac078f4295069f23a42567118b8907e0.zip

Repoll immediately if a protocol error happens during the authentication

attempt after a failed opportunistic TLS upgrade. Gentoo Bug #163782 comment #9, reported by Takuto Matsuu. svn path=/branches/BRANCH_6-3/; revision=5044

Diffstat (limited to 'cram.c')

0 files changed, 0 insertions, 0 deletions

/* * kerberos.c -- Kerberos authentication (see RFC 1731). * * For license terms, see the file COPYING in this directory. */ #include "config.h" #ifdef KERBEROS_V4 #include <stdio.h> #include <string.h> #include <ctype.h> #if defined(STDC_HEADERS) #include <stdlib.h> #endif #include "fetchmail.h" #include "socket.h" #include "kerberos.h" #include <sys/types.h> #include <netinet/in.h> /* for htonl/ntohl */ #include "i18n.h" #if SIZEOF_INT == 4 typedef int int32; #elif SIZEOF_SHORT == 4 typedef short int32; #elif SIZEOF_LONG == 4 typedef long int32; #else #error Cannot deduce a 32-bit-type #endif int do_rfc1731(int sock, char *command, char *truename) /* authenticate as per RFC1731 -- note 32-bit integer requirement here */ { int result = 0, len; char buf1[4096], buf2[4096]; union { int32 cint; char cstr[4]; } challenge1, challenge2; char srvinst[INST_SZ]; char *p; char srvrealm[REALM_SZ]; KTEXT_ST authenticator; CREDENTIALS credentials; char tktuser[MAX_K_NAME_SZ+1+INST_SZ+1+REALM_SZ+1]; char tktinst[INST_SZ]; char tktrealm[REALM_SZ]; des_cblock session; des_key_schedule schedule; gen_send(sock, "%s KERBEROS_V4", command); /* The data encoded in the first ready response contains a random * 32-bit number in network byte order. The client should respond * with a Kerberos ticket and an authenticator for the principal * "imap.hostname@realm", where "hostname" is the first component * of the host name of the server with all letters in lower case * and where "realm" is the Kerberos realm of the server. The * encrypted checksum field included within the Kerberos * authenticator should contain the server provided 32-bit number * in network byte order. */ if ((result = gen_recv(sock, buf1, sizeof buf1)) != 0) { return result; } len = from64tobits(challenge1.cstr, buf1, sizeof(challenge1.cstr)); if (len < 0) { report(stderr, GT_("could not decode initial BASE64 challenge\n")); return PS_AUTHFAIL; } /* this patch by Dan Root <dar@thekeep.org> solves an endianess * problem. */ { char tmp[4]; *(int *)tmp = ntohl(*(int *) challenge1.cstr); memcpy(challenge1.cstr, tmp, sizeof(tmp)); } /* Client responds with a Kerberos ticket and an authenticator for * the principal "imap.hostname@realm" where "hostname" is the * first component of the host name of the server with all letters * in lower case and where "realm" is the Kerberos realm of the * server. The encrypted checksum field included within the * Kerberos authenticator should contain the server-provided * 32-bit number in network byte order. */ strncpy(srvinst, truename, (sizeof srvinst)-1); srvinst[(sizeof srvinst)-1] = '\0'; for (p = srvinst; *p; p++) { if (isupper((unsigned char)*p)) { *p = tolower((unsigned char)*p); } } strncpy(srvrealm, (char *)krb_realmofhost(srvinst), (sizeof srvrealm)-1); srvrealm[(sizeof srvrealm)-1] = '\0'; if ((p = strchr(srvinst, '.')) != NULL) { *p = '\0'; } result = krb_mk_req(&authenticator, "imap", srvinst, srvrealm, 0); if (result) { report(stderr, "krb_mq_req: %s\n", krb_get_err_text(result)); return PS_AUTHFAIL; } result = krb_get_cred("imap", srvinst, srvrealm, &credentials); if (result) { report(stderr, "krb_get_cred: %s\n", krb_get_err_text(result)); return PS_AUTHFAIL; } memcpy(session, credentials.session, sizeof session); memset(&credentials, 0, sizeof credentials); des_key_sched(&session, schedule); result = krb_get_tf_fullname(TKT_FILE, tktuser, tktinst, tktrealm); if (result) { report(stderr, "krb_get_tf_fullname: %s\n", krb_get_err_text(result)); return PS_AUTHFAIL; } #ifdef __UNUSED__ /* * Andrew H. Chatham <andrew.chatham@duke.edu> alleges that this check * is not necessary and has consistently been messing him up. */ if (strcmp(tktuser, user) != 0) { report(stderr, GT_("principal %s in ticket does not match -u %s\n"), tktuser, user); return PS_AUTHFAIL; } #endif /* __UNUSED__ */ if (tktinst[0]) { report(stderr, GT_("non-null instance (%s) might cause strange behavior\n"), tktinst); strlcat(tktuser, ".", sizeof(tktuser)); strlcat(tktuser, tktinst, sizeof(tktuser)); } if (strcmp(tktrealm, srvrealm) != 0) { strlcat(tktuser, "@", sizeof(tktuser)); strlcat(tktuser, tktrealm, sizeof(tktuser)); } result = krb_mk_req(&authenticator, "imap", srvinst, srvrealm, challenge1.cint); if (result) { report(stderr, "krb_mq_req: %s\n", krb_get_err_text(result)); return PS_AUTHFAIL; } to64frombits(buf1, authenticator.dat, authenticator.length); if (outlevel >= O_MONITOR) { report(stdout, "IMAP> %s\n", buf1); } strcat(buf1, "\r\n"); SockWrite(sock, buf1, strlen(buf1)); /* Upon decrypting and verifying the ticket and authenticator, the * server should verify that the contained checksum field equals * the original server provided random 32-bit number. Should the * verification be successful, the server must add one to the * checksum and construct 8 octets of data, with the first four * octets containing the incremented checksum in network byte * order, the fifth octet containing a bit-mask specifying the * protection mechanisms supported by the server, and the sixth * through eighth octets containing, in network byte order, the * maximum cipher-text buffer size the server is able to receive. * The server must encrypt the 8 octets of data in the session key * and issue that encrypted data in a second ready response. The * client should consider the server authenticated if the first * four octets the un-encrypted data is equal to one plus the * checksum it previously sent. */ if ((result = gen_recv(sock, buf1, sizeof buf1)) != 0) return result; /* The client must construct data with the first four octets * containing the original server-issued checksum in network byte * order, the fifth octet containing the bit-mask specifying the * selected protection mechanism, the sixth through eighth octets * containing in network byte order the maximum cipher-text buffer * size the client is able to receive, and the following octets * containing a user name string. The client must then append * from one to eight octets so that the length of the data is a * multiple of eight octets. The client must then PCBC encrypt the * data with the session key and respond to the second ready * response with the encrypted data. The server decrypts the data * and verifies the contained checksum. The username field * identifies the user for whom subsequent IMAP operations are to * be performed; the server must verify that the principal * identified in the Kerberos ticket is authorized to connect as * that user. After these verifications, the authentication * process is complete. */ len = from64tobits(buf2, buf1, sizeof(buf2)); if (len < 0) { report(stderr, GT_("could not decode BASE64 ready response\n")); return PS_AUTHFAIL; } des_ecb_encrypt((des_cblock *)buf2, (des_cblock *)buf2, schedule, 0); memcpy(challenge2.cstr, buf2, 4); if ((int32)ntohl(challenge2.cint) != challenge1.cint + 1) { report(stderr, GT_("challenge mismatch\n")); return PS_AUTHFAIL; } memset(authenticator.dat, 0, sizeof authenticator.dat); result = htonl(challenge1.cint); memcpy(authenticator.dat, &result, sizeof result); /* The protection mechanisms and their corresponding bit-masks are as * follows: * * 1 No protection mechanism * 2 Integrity (krb_mk_safe) protection * 4 Privacy (krb_mk_priv) protection */ authenticator.dat[4] = 1; len = strlen(tktuser); strncpy((char *)authenticator.dat+8, tktuser, len); authenticator.length = len + 8 + 1; while (authenticator.length & 7) { authenticator.length++; } des_pcbc_encrypt((const unsigned char *)authenticator.dat, (unsigned char *)authenticator.dat, authenticator.length, schedule, &session, 1); to64frombits(buf1, authenticator.dat, authenticator.length); /* ship down the response, accept the server's error/ok indication */ suppress_tags = TRUE; result = gen_transact(sock, buf1, strlen(buf1)); suppress_tags = FALSE; if (result) return(result); else return(PS_SUCCESS); } #endif /* KERBEROS_V4 */ /* kerberos.c ends here */


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