1 /*++
2 /* NAME
3 /* tls_prng_file 3
4 /* SUMMARY
5 /* seed OpenSSL PRNG from entropy file
6 /* SYNOPSIS
7 /* #include <tls_prng_src.h>
8 /*
9 /* TLS_PRNG_SRC *tls_prng_file_open(name, timeout)
10 /* const char *name;
11 /* int timeout;
12 /*
13 /* ssize_t tls_prng_file_read(fh, length)
14 /* TLS_PRNG_SRC *fh;
15 /* size_t length;
16 /*
17 /* int tls_prng_file_close(fh)
18 /* TLS_PRNG_SRC *fh;
19 /* DESCRIPTION
20 /* tls_prng_file_open() open the specified file and returns
21 /* a handle that should be used with all subsequent access.
22 /*
23 /* tls_prng_file_read() reads the requested number of bytes from
24 /* the entropy file and updates the OpenSSL PRNG. The file is not
25 /* locked for shared or exclusive access.
26 /*
27 /* tls_prng_file_close() closes the specified entropy file
28 /* and releases memory that was allocated for the handle.
29 /*
30 /* Arguments:
31 /* .IP name
32 /* The pathname of the entropy file.
33 /* .IP length
34 /* The number of bytes to read from the entropy file.
35 /* .IP timeout
36 /* Time limit on individual I/O operations.
37 /* DIAGNOSTICS
38 /* tls_prng_file_open() returns a null pointer on error.
39 /*
40 /* tls_prng_file_read() returns -1 on error, the number
41 /* of bytes received on success.
42 /*
43 /* tls_prng_file_close() returns -1 on error, 0 on success.
44 /*
45 /* In all cases the errno variable indicates the type of error.
46 /* LICENSE
47 /* .ad
48 /* .fi
49 /* The Secure Mailer license must be distributed with this software.
50 /* AUTHOR(S)
51 /* Wietse Venema
52 /* IBM T.J. Watson Research
53 /* P.O. Box 704
54 /* Yorktown Heights, NY 10598, USA
55 /*--*/
56
57 /* System library. */
58
59 #include <sys_defs.h>
60 #include <fcntl.h>
61 #include <unistd.h>
62 #include <limits.h>
63 #include <errno.h>
64
65 /* OpenSSL library. */
66
67 #ifdef USE_TLS
68 #include <openssl/rand.h> /* For the PRNG */
69
70 /* Utility library. */
71
72 #include <msg.h>
73 #include <mymalloc.h>
74 #include <connect.h>
75 #include <iostuff.h>
76
77 /* TLS library. */
78
79 #include <tls_prng.h>
80
81 /* tls_prng_file_open - open entropy file */
82
tls_prng_file_open(const char * name,int timeout)83 TLS_PRNG_SRC *tls_prng_file_open(const char *name, int timeout)
84 {
85 const char *myname = "tls_prng_file_open";
86 TLS_PRNG_SRC *fh;
87 int fd;
88
89 if ((fd = open(name, O_RDONLY, 0)) < 0) {
90 if (msg_verbose)
91 msg_info("%s: cannot open entropy file %s: %m", myname, name);
92 return (0);
93 } else {
94 fh = (TLS_PRNG_SRC *) mymalloc(sizeof(*fh));
95 fh->fd = fd;
96 fh->name = mystrdup(name);
97 fh->timeout = timeout;
98 if (msg_verbose)
99 msg_info("%s: opened entropy file %s", myname, name);
100 return (fh);
101 }
102 }
103
104 /* tls_prng_file_read - update internal PRNG from entropy file */
105
tls_prng_file_read(TLS_PRNG_SRC * fh,size_t len)106 ssize_t tls_prng_file_read(TLS_PRNG_SRC *fh, size_t len)
107 {
108 const char *myname = "tls_prng_file_read";
109 char buffer[8192];
110 ssize_t to_read;
111 ssize_t count;
112
113 if (msg_verbose)
114 msg_info("%s: seed internal pool from file %s", myname, fh->name);
115
116 if (lseek(fh->fd, 0, SEEK_SET) < 0) {
117 if (msg_verbose)
118 msg_info("cannot seek entropy file %s: %m", fh->name);
119 return (-1);
120 }
121 errno = 0;
122 for (to_read = len; to_read > 0; to_read -= count) {
123 if ((count = timed_read(fh->fd, buffer, to_read > sizeof(buffer) ?
124 sizeof(buffer) : to_read,
125 fh->timeout, (void *) 0)) < 0) {
126 if (msg_verbose)
127 msg_info("cannot read entropy file %s: %m", fh->name);
128 return (-1);
129 }
130 if (count == 0)
131 break;
132 RAND_seed(buffer, count);
133 }
134 if (msg_verbose)
135 msg_info("read %ld bytes from entropy file %s: %m",
136 (long) (len - to_read), fh->name);
137 return (len - to_read);
138 }
139
140 /* tls_prng_file_close - close entropy file */
141
tls_prng_file_close(TLS_PRNG_SRC * fh)142 int tls_prng_file_close(TLS_PRNG_SRC *fh)
143 {
144 const char *myname = "tls_prng_file_close";
145 int err;
146
147 if (msg_verbose)
148 msg_info("%s: close entropy file %s", myname, fh->name);
149 err = close(fh->fd);
150 myfree(fh->name);
151 myfree((void *) fh);
152 return (err);
153 }
154
155 #endif
156