Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * be-secure-common.c
4 : *
5 : * common implementation-independent SSL support code
6 : *
7 : * While be-secure.c contains the interfaces that the rest of the
8 : * communications code calls, this file contains support routines that are
9 : * used by the library-specific implementations such as be-secure-openssl.c.
10 : *
11 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
12 : * Portions Copyright (c) 1994, Regents of the University of California
13 : *
14 : * IDENTIFICATION
15 : * src/backend/libpq/be-secure-common.c
16 : *
17 : *-------------------------------------------------------------------------
18 : */
19 :
20 : #include "postgres.h"
21 :
22 : #include <sys/stat.h>
23 : #include <unistd.h>
24 :
25 : #include "common/percentrepl.h"
26 : #include "common/string.h"
27 : #include "libpq/libpq.h"
28 : #include "storage/fd.h"
29 :
30 : /*
31 : * Run ssl_passphrase_command
32 : *
33 : * prompt will be substituted for %p. is_server_start determines the loglevel
34 : * of error messages.
35 : *
36 : * The result will be put in buffer buf, which is of size size. The return
37 : * value is the length of the actual result.
38 : */
39 : int
40 12 : run_ssl_passphrase_command(const char *prompt, bool is_server_start, char *buf, int size)
41 : {
42 12 : int loglevel = is_server_start ? ERROR : LOG;
43 : char *command;
44 : FILE *fh;
45 : int pclose_rc;
46 12 : size_t len = 0;
47 :
48 : Assert(prompt);
49 : Assert(size > 0);
50 12 : buf[0] = '\0';
51 :
52 12 : command = replace_percent_placeholders(ssl_passphrase_command, "ssl_passphrase_command", "p", prompt);
53 :
54 12 : fh = OpenPipeStream(command, "r");
55 12 : if (fh == NULL)
56 : {
57 0 : ereport(loglevel,
58 : (errcode_for_file_access(),
59 : errmsg("could not execute command \"%s\": %m",
60 : command)));
61 0 : goto error;
62 : }
63 :
64 12 : if (!fgets(buf, size, fh))
65 : {
66 0 : if (ferror(fh))
67 : {
68 0 : explicit_bzero(buf, size);
69 0 : ereport(loglevel,
70 : (errcode_for_file_access(),
71 : errmsg("could not read from command \"%s\": %m",
72 : command)));
73 0 : goto error;
74 : }
75 : }
76 :
77 12 : pclose_rc = ClosePipeStream(fh);
78 12 : if (pclose_rc == -1)
79 : {
80 0 : explicit_bzero(buf, size);
81 0 : ereport(loglevel,
82 : (errcode_for_file_access(),
83 : errmsg("could not close pipe to external command: %m")));
84 0 : goto error;
85 : }
86 12 : else if (pclose_rc != 0)
87 : {
88 : char *reason;
89 :
90 0 : explicit_bzero(buf, size);
91 0 : reason = wait_result_to_str(pclose_rc);
92 0 : ereport(loglevel,
93 : (errcode_for_file_access(),
94 : errmsg("command \"%s\" failed",
95 : command),
96 : errdetail_internal("%s", reason)));
97 0 : pfree(reason);
98 0 : goto error;
99 : }
100 :
101 : /* strip trailing newline and carriage return */
102 12 : len = pg_strip_crlf(buf);
103 :
104 12 : error:
105 12 : pfree(command);
106 12 : return len;
107 : }
108 :
109 :
110 : /*
111 : * Check permissions for SSL key files.
112 : */
113 : bool
114 64 : check_ssl_key_file_permissions(const char *ssl_key_file, bool isServerStart)
115 : {
116 64 : int loglevel = isServerStart ? FATAL : LOG;
117 : struct stat buf;
118 :
119 64 : if (stat(ssl_key_file, &buf) != 0)
120 : {
121 0 : ereport(loglevel,
122 : (errcode_for_file_access(),
123 : errmsg("could not access private key file \"%s\": %m",
124 : ssl_key_file)));
125 0 : return false;
126 : }
127 :
128 : /* Key file must be a regular file */
129 64 : if (!S_ISREG(buf.st_mode))
130 : {
131 0 : ereport(loglevel,
132 : (errcode(ERRCODE_CONFIG_FILE_ERROR),
133 : errmsg("private key file \"%s\" is not a regular file",
134 : ssl_key_file)));
135 0 : return false;
136 : }
137 :
138 : /*
139 : * Refuse to load key files owned by users other than us or root, and
140 : * require no public access to the key file. If the file is owned by us,
141 : * require mode 0600 or less. If owned by root, require 0640 or less to
142 : * allow read access through either our gid or a supplementary gid that
143 : * allows us to read system-wide certificates.
144 : *
145 : * Note that roughly similar checks are performed in
146 : * src/interfaces/libpq/fe-secure-openssl.c so any changes here may need
147 : * to be made there as well. The environment is different though; this
148 : * code can assume that we're not running as root.
149 : *
150 : * Ideally we would do similar permissions checks on Windows, but it is
151 : * not clear how that would work since Unix-style permissions may not be
152 : * available.
153 : */
154 : #if !defined(WIN32) && !defined(__CYGWIN__)
155 64 : if (buf.st_uid != geteuid() && buf.st_uid != 0)
156 : {
157 0 : ereport(loglevel,
158 : (errcode(ERRCODE_CONFIG_FILE_ERROR),
159 : errmsg("private key file \"%s\" must be owned by the database user or root",
160 : ssl_key_file)));
161 0 : return false;
162 : }
163 :
164 64 : if ((buf.st_uid == geteuid() && buf.st_mode & (S_IRWXG | S_IRWXO)) ||
165 64 : (buf.st_uid == 0 && buf.st_mode & (S_IWGRP | S_IXGRP | S_IRWXO)))
166 : {
167 0 : ereport(loglevel,
168 : (errcode(ERRCODE_CONFIG_FILE_ERROR),
169 : errmsg("private key file \"%s\" has group or world access",
170 : ssl_key_file),
171 : errdetail("File must have permissions u=rw (0600) or less if owned by the database user, or permissions u=rw,g=r (0640) or less if owned by root.")));
172 0 : return false;
173 : }
174 : #endif
175 :
176 64 : return true;
177 : }
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