diff options
author | Colin Watson <cjwatson@debian.org> | 2011-09-06 09:45:52 +0100 |
---|---|---|
committer | Colin Watson <cjwatson@debian.org> | 2011-09-06 09:45:52 +0100 |
commit | f38224d546cdde55f45c13d3d8225d273a3f920e (patch) | |
tree | a91a26b88ac90dc72d0ea3767feabb341eaa50a8 /entropy.c | |
parent | 338146a3fc257e216fe5c10fe40e6896b40d7739 (diff) | |
parent | e90790abaf031e037f444a6658e136e48577ea49 (diff) |
merge 5.9p1
Diffstat (limited to 'entropy.c')
-rw-r--r-- | entropy.c | 238 |
1 files changed, 139 insertions, 99 deletions
@@ -25,19 +25,19 @@ | |||
25 | #include "includes.h" | 25 | #include "includes.h" |
26 | 26 | ||
27 | #include <sys/types.h> | 27 | #include <sys/types.h> |
28 | #include <sys/wait.h> | 28 | #include <sys/socket.h> |
29 | 29 | #ifdef HAVE_SYS_UN_H | |
30 | #ifdef HAVE_SYS_STAT_H | 30 | # include <sys/un.h> |
31 | # include <sys/stat.h> | ||
32 | #endif | 31 | #endif |
33 | 32 | ||
34 | #ifdef HAVE_FCNTL_H | 33 | #include <netinet/in.h> |
35 | # include <fcntl.h> | 34 | #include <arpa/inet.h> |
36 | #endif | 35 | |
37 | #include <stdarg.h> | 36 | #include <errno.h> |
38 | #include <string.h> | ||
39 | #include <signal.h> | 37 | #include <signal.h> |
38 | #include <string.h> | ||
40 | #include <unistd.h> | 39 | #include <unistd.h> |
40 | #include <stddef.h> /* for offsetof */ | ||
41 | 41 | ||
42 | #include <openssl/rand.h> | 42 | #include <openssl/rand.h> |
43 | #include <openssl/crypto.h> | 43 | #include <openssl/crypto.h> |
@@ -54,118 +54,128 @@ | |||
54 | /* | 54 | /* |
55 | * Portable OpenSSH PRNG seeding: | 55 | * Portable OpenSSH PRNG seeding: |
56 | * If OpenSSL has not "internally seeded" itself (e.g. pulled data from | 56 | * If OpenSSL has not "internally seeded" itself (e.g. pulled data from |
57 | * /dev/random), then we execute a "ssh-rand-helper" program which | 57 | * /dev/random), then collect RANDOM_SEED_SIZE bytes of randomness from |
58 | * collects entropy and writes it to stdout. The child program must | 58 | * PRNGd. |
59 | * write at least RANDOM_SEED_SIZE bytes. The child is run with stderr | ||
60 | * attached, so error/debugging output should be visible. | ||
61 | * | ||
62 | * XXX: we should tell the child how many bytes we need. | ||
63 | */ | 59 | */ |
64 | |||
65 | #ifndef OPENSSL_PRNG_ONLY | 60 | #ifndef OPENSSL_PRNG_ONLY |
61 | |||
66 | #define RANDOM_SEED_SIZE 48 | 62 | #define RANDOM_SEED_SIZE 48 |
67 | static uid_t original_uid, original_euid; | ||
68 | #endif | ||
69 | 63 | ||
70 | void | 64 | /* |
71 | seed_rng(void) | 65 | * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon |
66 | * listening either on 'tcp_port', or via Unix domain socket at * | ||
67 | * 'socket_path'. | ||
68 | * Either a non-zero tcp_port or a non-null socket_path must be | ||
69 | * supplied. | ||
70 | * Returns 0 on success, -1 on error | ||
71 | */ | ||
72 | int | ||
73 | get_random_bytes_prngd(unsigned char *buf, int len, | ||
74 | unsigned short tcp_port, char *socket_path) | ||
72 | { | 75 | { |
73 | #ifndef OPENSSL_PRNG_ONLY | 76 | int fd, addr_len, rval, errors; |
74 | int devnull; | 77 | u_char msg[2]; |
75 | int p[2]; | 78 | struct sockaddr_storage addr; |
76 | pid_t pid; | 79 | struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; |
77 | int ret; | 80 | struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; |
78 | unsigned char buf[RANDOM_SEED_SIZE]; | 81 | mysig_t old_sigpipe; |
79 | mysig_t old_sigchld; | 82 | |
83 | /* Sanity checks */ | ||
84 | if (socket_path == NULL && tcp_port == 0) | ||
85 | fatal("You must specify a port or a socket"); | ||
86 | if (socket_path != NULL && | ||
87 | strlen(socket_path) >= sizeof(addr_un->sun_path)) | ||
88 | fatal("Random pool path is too long"); | ||
89 | if (len <= 0 || len > 255) | ||
90 | fatal("Too many bytes (%d) to read from PRNGD", len); | ||
91 | |||
92 | memset(&addr, '\0', sizeof(addr)); | ||
93 | |||
94 | if (tcp_port != 0) { | ||
95 | addr_in->sin_family = AF_INET; | ||
96 | addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); | ||
97 | addr_in->sin_port = htons(tcp_port); | ||
98 | addr_len = sizeof(*addr_in); | ||
99 | } else { | ||
100 | addr_un->sun_family = AF_UNIX; | ||
101 | strlcpy(addr_un->sun_path, socket_path, | ||
102 | sizeof(addr_un->sun_path)); | ||
103 | addr_len = offsetof(struct sockaddr_un, sun_path) + | ||
104 | strlen(socket_path) + 1; | ||
105 | } | ||
80 | 106 | ||
81 | if (RAND_status() == 1) { | 107 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); |
82 | debug3("RNG is ready, skipping seeding"); | 108 | |
83 | return; | 109 | errors = 0; |
110 | rval = -1; | ||
111 | reopen: | ||
112 | fd = socket(addr.ss_family, SOCK_STREAM, 0); | ||
113 | if (fd == -1) { | ||
114 | error("Couldn't create socket: %s", strerror(errno)); | ||
115 | goto done; | ||
84 | } | 116 | } |
85 | 117 | ||
86 | debug3("Seeding PRNG from %s", SSH_RAND_HELPER); | 118 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { |
87 | 119 | if (tcp_port != 0) { | |
88 | if ((devnull = open("/dev/null", O_RDWR)) == -1) | 120 | error("Couldn't connect to PRNGD port %d: %s", |
89 | fatal("Couldn't open /dev/null: %s", strerror(errno)); | 121 | tcp_port, strerror(errno)); |
90 | if (pipe(p) == -1) | 122 | } else { |
91 | fatal("pipe: %s", strerror(errno)); | 123 | error("Couldn't connect to PRNGD socket \"%s\": %s", |
92 | 124 | addr_un->sun_path, strerror(errno)); | |
93 | old_sigchld = signal(SIGCHLD, SIG_DFL); | ||
94 | if ((pid = fork()) == -1) | ||
95 | fatal("Couldn't fork: %s", strerror(errno)); | ||
96 | if (pid == 0) { | ||
97 | dup2(devnull, STDIN_FILENO); | ||
98 | dup2(p[1], STDOUT_FILENO); | ||
99 | /* Keep stderr open for errors */ | ||
100 | close(p[0]); | ||
101 | close(p[1]); | ||
102 | close(devnull); | ||
103 | |||
104 | if (original_uid != original_euid && | ||
105 | ( seteuid(getuid()) == -1 || | ||
106 | setuid(original_uid) == -1) ) { | ||
107 | fprintf(stderr, "(rand child) setuid(%li): %s\n", | ||
108 | (long int)original_uid, strerror(errno)); | ||
109 | _exit(1); | ||
110 | } | 125 | } |
111 | 126 | goto done; | |
112 | execl(SSH_RAND_HELPER, "ssh-rand-helper", NULL); | ||
113 | fprintf(stderr, "(rand child) Couldn't exec '%s': %s\n", | ||
114 | SSH_RAND_HELPER, strerror(errno)); | ||
115 | _exit(1); | ||
116 | } | 127 | } |
117 | 128 | ||
118 | close(devnull); | 129 | /* Send blocking read request to PRNGD */ |
119 | close(p[1]); | 130 | msg[0] = 0x02; |
131 | msg[1] = len; | ||
120 | 132 | ||
121 | memset(buf, '\0', sizeof(buf)); | 133 | if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { |
122 | ret = atomicio(read, p[0], buf, sizeof(buf)); | 134 | if (errno == EPIPE && errors < 10) { |
123 | if (ret == -1) | 135 | close(fd); |
124 | fatal("Couldn't read from ssh-rand-helper: %s", | 136 | errors++; |
137 | goto reopen; | ||
138 | } | ||
139 | error("Couldn't write to PRNGD socket: %s", | ||
125 | strerror(errno)); | 140 | strerror(errno)); |
126 | if (ret != sizeof(buf)) | 141 | goto done; |
127 | fatal("ssh-rand-helper child produced insufficient data"); | 142 | } |
128 | |||
129 | close(p[0]); | ||
130 | 143 | ||
131 | if (waitpid(pid, &ret, 0) == -1) | 144 | if (atomicio(read, fd, buf, len) != (size_t)len) { |
132 | fatal("Couldn't wait for ssh-rand-helper completion: %s", | 145 | if (errno == EPIPE && errors < 10) { |
146 | close(fd); | ||
147 | errors++; | ||
148 | goto reopen; | ||
149 | } | ||
150 | error("Couldn't read from PRNGD socket: %s", | ||
133 | strerror(errno)); | 151 | strerror(errno)); |
134 | signal(SIGCHLD, old_sigchld); | 152 | goto done; |
135 | 153 | } | |
136 | /* We don't mind if the child exits upon a SIGPIPE */ | ||
137 | if (!WIFEXITED(ret) && | ||
138 | (!WIFSIGNALED(ret) || WTERMSIG(ret) != SIGPIPE)) | ||
139 | fatal("ssh-rand-helper terminated abnormally"); | ||
140 | if (WEXITSTATUS(ret) != 0) | ||
141 | fatal("ssh-rand-helper exit with exit status %d", ret); | ||
142 | |||
143 | RAND_add(buf, sizeof(buf), sizeof(buf)); | ||
144 | memset(buf, '\0', sizeof(buf)); | ||
145 | 154 | ||
146 | #endif /* OPENSSL_PRNG_ONLY */ | 155 | rval = 0; |
147 | if (RAND_status() != 1) | 156 | done: |
148 | fatal("PRNG is not seeded"); | 157 | mysignal(SIGPIPE, old_sigpipe); |
158 | if (fd != -1) | ||
159 | close(fd); | ||
160 | return rval; | ||
149 | } | 161 | } |
150 | 162 | ||
151 | void | 163 | static int |
152 | init_rng(void) | 164 | seed_from_prngd(unsigned char *buf, size_t bytes) |
153 | { | 165 | { |
154 | /* | 166 | #ifdef PRNGD_PORT |
155 | * OpenSSL version numbers: MNNFFPPS: major minor fix patch status | 167 | debug("trying egd/prngd port %d", PRNGD_PORT); |
156 | * We match major, minor, fix and status (not patch) | 168 | if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0) |
157 | */ | 169 | return 0; |
158 | if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L) | 170 | #endif |
159 | fatal("OpenSSL version mismatch. Built against %lx, you " | 171 | #ifdef PRNGD_SOCKET |
160 | "have %lx", (u_long)OPENSSL_VERSION_NUMBER, SSLeay()); | 172 | debug("trying egd/prngd socket %s", PRNGD_SOCKET); |
161 | 173 | if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0) | |
162 | #ifndef OPENSSL_PRNG_ONLY | 174 | return 0; |
163 | original_uid = getuid(); | ||
164 | original_euid = geteuid(); | ||
165 | #endif | 175 | #endif |
176 | return -1; | ||
166 | } | 177 | } |
167 | 178 | ||
168 | #ifndef OPENSSL_PRNG_ONLY | ||
169 | void | 179 | void |
170 | rexec_send_rng_seed(Buffer *m) | 180 | rexec_send_rng_seed(Buffer *m) |
171 | { | 181 | { |
@@ -191,4 +201,34 @@ rexec_recv_rng_seed(Buffer *m) | |||
191 | RAND_add(buf, len, len); | 201 | RAND_add(buf, len, len); |
192 | } | 202 | } |
193 | } | 203 | } |
204 | #endif /* OPENSSL_PRNG_ONLY */ | ||
205 | |||
206 | void | ||
207 | seed_rng(void) | ||
208 | { | ||
209 | #ifndef OPENSSL_PRNG_ONLY | ||
210 | unsigned char buf[RANDOM_SEED_SIZE]; | ||
194 | #endif | 211 | #endif |
212 | /* | ||
213 | * OpenSSL version numbers: MNNFFPPS: major minor fix patch status | ||
214 | * We match major, minor, fix and status (not patch) | ||
215 | */ | ||
216 | if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L) | ||
217 | fatal("OpenSSL version mismatch. Built against %lx, you " | ||
218 | "have %lx", (u_long)OPENSSL_VERSION_NUMBER, SSLeay()); | ||
219 | |||
220 | #ifndef OPENSSL_PRNG_ONLY | ||
221 | if (RAND_status() == 1) { | ||
222 | debug3("RNG is ready, skipping seeding"); | ||
223 | return; | ||
224 | } | ||
225 | |||
226 | if (seed_from_prngd(buf, sizeof(buf)) == -1) | ||
227 | fatal("Could not obtain seed from PRNGd"); | ||
228 | RAND_add(buf, sizeof(buf), sizeof(buf)); | ||
229 | memset(buf, '\0', sizeof(buf)); | ||
230 | |||
231 | #endif /* OPENSSL_PRNG_ONLY */ | ||
232 | if (RAND_status() != 1) | ||
233 | fatal("PRNG is not seeded"); | ||
234 | } | ||