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Diffstat (limited to 'mcop/md5auth.cc')
| -rw-r--r-- | mcop/md5auth.cc | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/mcop/md5auth.cc b/mcop/md5auth.cc new file mode 100644 index 0000000..1e6fe1a --- /dev/null +++ b/mcop/md5auth.cc @@ -0,0 +1,213 @@ + /* + + Copyright (C) 2000 Stefan Westerfeld + stefan@space.twc.de + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public License + along with this library; see the file COPYING.LIB. If not, write to + the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. + + */ + +#include <config.h> + +#include <sys/utsname.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <assert.h> +#include <stdlib.h> + +#if TIME_WITH_SYS_TIME +# include <sys/time.h> +# include <time.h> +#elif HAVE_SYS_TIME_H +# include <sys/time.h> +#else +# include <time.h> +#endif + +#include "md5.h" +#include "md5auth.h" +#include "debug.h" + +// MD5_BINARY_LEN is defined in md5.h +#define MD5_COOKIE_LEN (MD5_BINARY_LEN*2) +#define MD5_MANGLE_LEN (MD5_COOKIE_LEN*2) + + + +struct random_info { + struct timeval tv; + int pid; + struct utsname un; + char dev_urandom[MD5_BINARY_LEN]; + char seed[MD5_COOKIE_LEN+1]; + int number; +}; + +static char md5_seed[MD5_COOKIE_LEN+1]; +static char md5_cookie[MD5_COOKIE_LEN+1]; +static int md5_init = 0; +static int md5_random_cookie_number = 0; + +static char *md5_to_ascii_overwrite(char *md5) +{ + char outascii[MD5_COOKIE_LEN+1]; + char *result; + int i; + + // convert to readable text + for(i = 0; i < MD5_BINARY_LEN; i++) { + sprintf(&outascii[i*2],"%02x",md5[i] & 0xff); + } + outascii[MD5_COOKIE_LEN] = 0; + result = strdup(outascii); + + // try to zero out traces + memset(md5,0,MD5_BINARY_LEN); + memset(outascii,0,MD5_COOKIE_LEN); + + // well, here it is + return result; +} + +char *arts_md5_auth_mangle(const char *cookie) +{ + char mangle[MD5_MANGLE_LEN+1]; + char out[MD5_BINARY_LEN]; + assert(md5_init); + + // concat the two cookies and mangle them to a new one + strncpy(mangle,md5_cookie, MD5_COOKIE_LEN); + mangle[MD5_COOKIE_LEN] = 0; + strncat(mangle,cookie, MD5_COOKIE_LEN); + mangle[MD5_MANGLE_LEN] = 0; + arts_md5sum((unsigned char *)mangle,MD5_MANGLE_LEN,out); + + // try to zero out traces + memset(mangle,0,MD5_MANGLE_LEN); + + return md5_to_ascii_overwrite(out); +} + +char *arts_md5_auth_mkcookie() +{ + struct random_info r; + char out[MD5_BINARY_LEN]; + int rndfd; + + memset(&r,0,sizeof(struct random_info)); + + // collect some "random" system information + gettimeofday(&r.tv,0); + r.pid = getpid(); + uname(&r.un); + + // linux random device ; if that works, we have good random anyway, the + // above are just helpers for the case that it doesn't + rndfd = open("/dev/urandom",O_RDONLY); + if(rndfd != -1) + { + read(rndfd,r.dev_urandom,MD5_BINARY_LEN); + close(rndfd); + } + + // ensure that two cookies that are requested very shortly after each + // other (so that it looks like "at the same time") won't be the same + r.number = ++md5_random_cookie_number; + + // this is some seed from a file which is updated sometimes with a + // new "arts_md5_auth_mkcookie()" after initialization + strncpy(r.seed,md5_seed,MD5_COOKIE_LEN); + + // build hash value of all information + arts_md5sum((unsigned char *)&r,sizeof(struct random_info),out); + + // zero out traces and return + memset(&r,0,sizeof(struct random_info)); + return md5_to_ascii_overwrite(out); +} + +const char *arts_md5_auth_cookie() +{ + assert(md5_init); + return md5_cookie; +} + +static int md5_load_cookie(const char *filename, char *cookie) +{ + int fd = open(filename,O_RDONLY); + int i; + + if(fd != -1) { + struct stat st; + for(i=0;i<5;i++) { + fstat(fd,&st); + if(st.st_size == MD5_COOKIE_LEN) { + lseek(fd, 0, SEEK_SET); + if(read(fd,cookie,MD5_COOKIE_LEN) == MD5_COOKIE_LEN) + { + cookie[MD5_COOKIE_LEN] = 0; + close(fd); + return 1; + } + } + arts_warning("MCOP: " + "authority file has wrong size (just being written?)"); + sleep(1); + } + } + return 0; +} + +void arts_md5_auth_init_seed(const char *seedname) +{ + // don't care if it works - no harm is being done if it doesn't + md5_load_cookie(seedname,md5_seed); + + /* + * maxage ensures that not everybody will try to update the seed + * at the same time, while it will take at most 5 hours between + * updates (if there are any initialization calls) + */ + struct stat st; + int maxage = 300 + (getpid() & 0xfff)*4; + int lstat_result = lstat(seedname,&st); + if(lstat_result != 0 || (time(0) - st.st_mtime) > maxage) + { + int fd = open(seedname,O_TRUNC|O_CREAT|O_WRONLY,S_IRUSR|S_IWUSR); + if(fd != -1) { + char *cookie = arts_md5_auth_mkcookie(); + write(fd,cookie,strlen(cookie)); + memset(cookie,0,strlen(cookie)); + free(cookie); + close(fd); + } + } +} + +bool arts_md5_auth_set_cookie(const char *cookie) +{ + if(strlen(cookie) != MD5_COOKIE_LEN) + return false; + + strncpy(md5_cookie,cookie,MD5_COOKIE_LEN); + md5_cookie[MD5_COOKIE_LEN] = 0; + md5_init = 1; + return true; +} |