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port-linux.c

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/home/opencoverage/opencoverage/guest-scripts/openssh/src/openbsd-compat/port-linux.c

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1 /* -

4 * -

5 * Permission to use, copy, modify, and distribute this software for any -

6 * purpose with or without fee is hereby granted, provided that the above -

7 * copyright notice and this permission notice appear in all copies. -

8 * -

9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES -

10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF -

11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR -

12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES -

13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN -

14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF -

15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. -

16 */ -

17 -

18 /* -

19 * Linux-specific portability code - just SELinux support at present -

20 */ -

21 -

22 #include "includes.h" -

23 -

24 #if defined(WITH_SELINUX) || defined(LINUX_OOM_ADJUST) -

25 #include <errno.h> -

26 #include <stdarg.h> -

27 #include <string.h> -

28 #include <stdio.h> -

29 #include <stdlib.h> -

30 -

31 #include "log.h" -

32 #include "xmalloc.h" -

33 #include "port-linux.h" -

34 -

35 #ifdef WITH_SELINUX -

36 #include <selinux/selinux.h> -

37 #include <selinux/get_context_list.h> -

38 -

39 #ifndef SSH_SELINUX_UNCONFINED_TYPE -

40 # define SSH_SELINUX_UNCONFINED_TYPE ":unconfined_t:" -

41 #endif -

42 -

43 /* Wrapper around is_selinux_enabled() to log its return value once only */ -

44 int -

45 ssh_selinux_enabled(void) -

46 { -

47 static int enabled = -1; -

48 -

49 if (enabled == -1) { -

50 enabled = (is_selinux_enabled() == 1); -

51 debug("SELinux support %s", enabled ? "enabled" : "disabled"); -

52 } -

53 -

54 return (enabled); -

55 } -

56 -

57 /* Return the default security context for the given username */ -

58 static security_context_t -

59 ssh_selinux_getctxbyname(char *pwname) -

60 { -

61 security_context_t sc = NULL; -

62 char *sename = NULL, *lvl = NULL; -

63 int r; -

64 -

65 #ifdef HAVE_GETSEUSERBYNAME -

66 if (getseuserbyname(pwname, &sename, &lvl) != 0) -

67 return NULL; -

68 #else -

69 sename = pwname; -

70 lvl = NULL; -

71 #endif -

72 -

73 #ifdef HAVE_GET_DEFAULT_CONTEXT_WITH_LEVEL -

74 r = get_default_context_with_level(sename, lvl, NULL, &sc); -

75 #else -

76 r = get_default_context(sename, NULL, &sc); -

77 #endif -

78 -

79 if (r != 0) { -

80 switch (security_getenforce()) { -

81 case -1: -

82 fatal("%s: ssh_selinux_getctxbyname: " -

83 "security_getenforce() failed", __func__); -

84 case 0: -

85 error("%s: Failed to get default SELinux security " -

86 "context for %s", __func__, pwname); -

87 sc = NULL; -

88 break; -

89 default: -

90 fatal("%s: Failed to get default SELinux security " -

91 "context for %s (in enforcing mode)", -

92 __func__, pwname); -

93 } -

94 } -

95 -

96 #ifdef HAVE_GETSEUSERBYNAME -

97 free(sename); -

98 free(lvl); -

99 #endif -

100 -

101 return sc; -

102 } -

103 -

104 /* Set the execution context to the default for the specified user */ -

105 void -

106 ssh_selinux_setup_exec_context(char *pwname) -

107 { -

108 security_context_t user_ctx = NULL; -

109 -

110 if (!ssh_selinux_enabled()) -

111 return; -

112 -

113 debug3("%s: setting execution context", __func__); -

114 -

115 user_ctx = ssh_selinux_getctxbyname(pwname); -

116 if (setexeccon(user_ctx) != 0) { -

117 switch (security_getenforce()) { -

118 case -1: -

119 fatal("%s: security_getenforce() failed", __func__); -

120 case 0: -

121 error("%s: Failed to set SELinux execution " -

122 "context for %s", __func__, pwname); -

123 break; -

124 default: -

125 fatal("%s: Failed to set SELinux execution context " -

126 "for %s (in enforcing mode)", __func__, pwname); -

127 } -

128 } -

129 if (user_ctx != NULL) -

130 freecon(user_ctx); -

131 -

132 debug3("%s: done", __func__); -

133 } -

134 -

135 /* Set the TTY context for the specified user */ -

136 void -

137 ssh_selinux_setup_pty(char *pwname, const char *tty) -

138 { -

139 security_context_t new_tty_ctx = NULL; -

140 security_context_t user_ctx = NULL; -

141 security_context_t old_tty_ctx = NULL; -

142 security_class_t chrclass; -

143 -

144 if (!ssh_selinux_enabled()) -

145 return; -

146 -

147 debug3("%s: setting TTY context on %s", __func__, tty); -

148 -

149 user_ctx = ssh_selinux_getctxbyname(pwname); -

150 -

151 /* XXX: should these calls fatal() upon failure in enforcing mode? */ -

152 -

153 if (getfilecon(tty, &old_tty_ctx) == -1) { -

154 error("%s: getfilecon: %s", __func__, strerror(errno)); -

155 goto out; -

156 } -

157 if ((chrclass = string_to_security_class("chr_file")) == 0) { -

158 error("%s: couldn't get security class for chr_file", __func__); -

159 goto out; -

160 } -

161 if (security_compute_relabel(user_ctx, old_tty_ctx, -

162 chrclass, &new_tty_ctx) != 0) { -

163 error("%s: security_compute_relabel: %s", -

164 __func__, strerror(errno)); -

165 goto out; -

166 } -

167 -

168 if (setfilecon(tty, new_tty_ctx) != 0) -

169 error("%s: setfilecon: %s", __func__, strerror(errno)); -

170 out: -

171 if (new_tty_ctx != NULL) -

172 freecon(new_tty_ctx); -

173 if (old_tty_ctx != NULL) -

174 freecon(old_tty_ctx); -

175 if (user_ctx != NULL) -

176 freecon(user_ctx); -

177 debug3("%s: done", __func__); -

178 } -

179 -

180 void -

181 ssh_selinux_change_context(const char *newname) -

182 { -

183 int len, newlen; -

184 char *oldctx, *newctx, *cx; -

185 void (*switchlog) (const char *fmt,...) = logit; -

186 -

187 if (!ssh_selinux_enabled()) -

188 return; -

189 -

190 if (getcon((security_context_t *)&oldctx) < 0) { -

191 logit("%s: getcon failed with %s", __func__, strerror(errno)); -

192 return; -

193 } -

194 if ((cx = index(oldctx, ':')) == NULL || (cx = index(cx + 1, ':')) == -

195 NULL) { -

196 logit ("%s: unparseable context %s", __func__, oldctx); -

197 return; -

198 } -

199 -

200 /* -

201 * Check whether we are attempting to switch away from an unconfined -

202 * security context. -

203 */ -

204 if (strncmp(cx, SSH_SELINUX_UNCONFINED_TYPE, -

205 sizeof(SSH_SELINUX_UNCONFINED_TYPE) - 1) == 0) -

206 switchlog = debug3; -

207 -

208 newlen = strlen(oldctx) + strlen(newname) + 1; -

209 newctx = xmalloc(newlen); -

210 len = cx - oldctx + 1; -

211 memcpy(newctx, oldctx, len); -

212 strlcpy(newctx + len, newname, newlen - len); -

213 if ((cx = index(cx + 1, ':'))) -

214 strlcat(newctx, cx, newlen); -

215 debug3("%s: setting context from '%s' to '%s'", __func__, -

216 oldctx, newctx); -

217 if (setcon(newctx) < 0) -

218 switchlog("%s: setcon %s from %s failed with %s", __func__, -

219 newctx, oldctx, strerror(errno)); -

220 free(oldctx); -

221 free(newctx); -

222 } -

223 -

224 void -

225 ssh_selinux_setfscreatecon(const char *path) -

226 { -

227 security_context_t context; -

228 -

229 if (!ssh_selinux_enabled()) -

230 return; -

231 if (path == NULL) { -

232 setfscreatecon(NULL); -

233 return; -

234 } -

235 if (matchpathcon(path, 0700, &context) == 0) -

236 setfscreatecon(context); -

237 } -

238 -

239 #endif /* WITH_SELINUX */ -

240 -

241 #ifdef LINUX_OOM_ADJUST -

242 /* -

243 * The magic "don't kill me" values, old and new, as documented in eg: -

244 * http://lxr.linux.no/#linux+v2.6.32/Documentation/filesystems/proc.txt -

245 * http://lxr.linux.no/#linux+v2.6.36/Documentation/filesystems/proc.txt -

246 */ -

247 -

248 static int oom_adj_save = INT_MIN; -

249 static char *oom_adj_path = NULL; -

250 struct { -

251 char *path; -

252 int value; -

253 } oom_adjust[] = { -

254 {"/proc/self/oom_score_adj", -1000}, /* kernels >= 2.6.36 */ -

255 {"/proc/self/oom_adj", -17}, /* kernels <= 2.6.35 */ -

256 {NULL, 0}, -

257 }; -

258 -

259 /* -

260 * Tell the kernel's out-of-memory killer to avoid sshd. -

261 * Returns the previous oom_adj value or zero. -

262 */ -

263 void -

264 oom_adjust_setup(void) -

265 { -

266 int i, value; -

267 FILE *fp; -

268 -

269 debug3("%s", __func__); -

270

for (i = 0; oom_adjust[i].path != NULL; i++) {

oom_adjust[i]....!= ((void *)0)	Description
TRUE	never evaluated
FALSE	never evaluated

271 oom_adj_path = oom_adjust[i].path; -

272 value = oom_adjust[i].value; -

273

if ((fp = fopen(oom_adj_path, "r+")) != NULL) {

(fp = fopen(oo...!= ((void *)0)	Description
TRUE	never evaluated
FALSE	never evaluated

274

if (fscanf(fp, "%d", &oom_adj_save) != 1)

fscanf(fp, "%d...adj_save) != 1	Description
TRUE	never evaluated
FALSE	never evaluated

275

verbose("error reading %s: %s", oom_adj_path,

never executed: verbose("error reading %s: %s", oom_adj_path, strerror( (*__errno_location ()) ));

276

strerror(errno));

never executed: verbose("error reading %s: %s", oom_adj_path, strerror( (*__errno_location ()) ));

277 else { -

278 rewind(fp); -

279

if (fprintf(fp, "%d\n", value) <= 0)

fprintf(fp, "%...", value) <= 0	Description
TRUE	never evaluated
FALSE	never evaluated

280

verbose("error writing %s: %s",

never executed: verbose("error writing %s: %s", oom_adj_path, strerror( (*__errno_location ()) ));

281

oom_adj_path, strerror(errno));

never executed: verbose("error writing %s: %s", oom_adj_path, strerror( (*__errno_location ()) ));

282 else -

283

debug("Set %s from %d to %d",

never executed: debug("Set %s from %d to %d", oom_adj_path, oom_adj_save, value);

284

oom_adj_path, oom_adj_save, value);

never executed: debug("Set %s from %d to %d", oom_adj_path, oom_adj_save, value);

285 } -

286 fclose(fp); -

287

return;

never executed: return;

288 } -

289

}

never executed: end of block

290 oom_adj_path = NULL; -

291

}

never executed: end of block

292 -

293 /* Restore the saved OOM adjustment */ -

294 void -

295 oom_adjust_restore(void) -

296 { -

297 FILE *fp; -

298 -

299 debug3("%s", __func__); -

300

if (oom_adj_save == INT_MIN || oom_adj_path == NULL ||

oom_adj_save =...x7fffffff - 1)	Description
TRUE	never evaluated
FALSE	never evaluated

oom_adj_path == ((void *)0)	Description
TRUE	never evaluated
FALSE	never evaluated

301

(fp = fopen(oom_adj_path, "w")) == NULL)

(fp = fopen(oo...== ((void *)0)	Description
TRUE	never evaluated
FALSE	never evaluated

302

return;

never executed: return;

303 -

304

if (fprintf(fp, "%d\n", oom_adj_save) <= 0)

fprintf(fp, "%...adj_save) <= 0	Description
TRUE	never evaluated
FALSE	never evaluated

305

verbose("error writing %s: %s", oom_adj_path, strerror(errno));

never executed: verbose("error writing %s: %s", oom_adj_path, strerror( (*__errno_location ()) ));

306 else -

307

debug("Set %s to %d", oom_adj_path, oom_adj_save);

never executed: debug("Set %s to %d", oom_adj_path, oom_adj_save);

308 -

309 fclose(fp); -

310

return;

never executed: return;

311 } -

312 #endif /* LINUX_OOM_ADJUST */ -

313 #endif /* WITH_SELINUX || LINUX_OOM_ADJUST */ -

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