| 1 |
zorry 11/01/25 23:07:38 |
| 2 |
|
| 3 |
Modified: hardenedfaq.xml |
| 4 |
Log: |
| 5 |
added the new hardenedfaq.xml for hardened proj |
| 6 |
|
| 7 |
Revision Changes Path |
| 8 |
1.25 xml/htdocs/proj/en/hardened/hardenedfaq.xml |
| 9 |
|
| 10 |
file : http://sources.gentoo.org/viewvc.cgi/gentoo/xml/htdocs/proj/en/hardened/hardenedfaq.xml?rev=1.25&view=markup |
| 11 |
plain: http://sources.gentoo.org/viewvc.cgi/gentoo/xml/htdocs/proj/en/hardened/hardenedfaq.xml?rev=1.25&content-type=text/plain |
| 12 |
diff : http://sources.gentoo.org/viewvc.cgi/gentoo/xml/htdocs/proj/en/hardened/hardenedfaq.xml?r1=1.24&r2=1.25 |
| 13 |
|
| 14 |
Index: hardenedfaq.xml |
| 15 |
=================================================================== |
| 16 |
RCS file: /var/cvsroot/gentoo/xml/htdocs/proj/en/hardened/hardenedfaq.xml,v |
| 17 |
retrieving revision 1.24 |
| 18 |
retrieving revision 1.25 |
| 19 |
diff -u -r1.24 -r1.25 |
| 20 |
--- hardenedfaq.xml 17 Aug 2010 22:35:05 -0000 1.24 |
| 21 |
+++ hardenedfaq.xml 25 Jan 2011 23:07:38 -0000 1.25 |
| 22 |
@@ -1,5 +1,6 @@ |
| 23 |
<?xml version="1.0" encoding="UTF-8"?> |
| 24 |
<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> |
| 25 |
+<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/proj/en/hardened/hardenedfaq.xml,v 1.25 2011/01/25 23:07:38 zorry Exp $ --> |
| 26 |
|
| 27 |
<guide link="/proj/en/hardened/hardenedfaq.xml" lang="en"> |
| 28 |
<title>Gentoo Hardened Frequently Asked Questions</title> |
| 29 |
@@ -15,148 +16,42 @@ |
| 30 |
<author title="Contributor"> |
| 31 |
<mail link="pageexec@××××××××.hu">The PaX Team</mail> |
| 32 |
</author> |
| 33 |
+<author title="Contributor"> |
| 34 |
+ <mail link="klondike@×××××××××.es">klondike</mail> |
| 35 |
+</author> |
| 36 |
+<author title="Contributor"> |
| 37 |
+ <mail link="zorry@g.o">Magnus Granberg</mail> |
| 38 |
+</author> |
| 39 |
+<author title="Contributor"> |
| 40 |
+ <mail link="blueness@g.o">Anthony G. Basile</mail> |
| 41 |
+</author> |
| 42 |
|
| 43 |
<abstract> |
| 44 |
Frequently Asked Questions that arise on the #gentoo-hardened IRC channel and |
| 45 |
the gentoo-hardened mailing list. |
| 46 |
</abstract> |
| 47 |
|
| 48 |
-<version>1.9</version> |
| 49 |
-<date>2006-02-18</date> |
| 50 |
+<version>3.2</version> |
| 51 |
+<date>2011-1-19</date> |
| 52 |
|
| 53 |
-<chapter> |
| 54 |
+<faqindex> |
| 55 |
<title>Questions</title> |
| 56 |
<section> |
| 57 |
-<title>General</title> |
| 58 |
-<body> |
| 59 |
- |
| 60 |
-<ul> |
| 61 |
- <li> |
| 62 |
- <uri link="#toolchain">What exactly is the "toolchain"?</uri> |
| 63 |
- </li> |
| 64 |
- <li> |
| 65 |
- <uri link="#whichisbetter">What should I use: grsecurity, RSBAC or |
| 66 |
- SELinux?</uri> |
| 67 |
- </li> |
| 68 |
- <li> |
| 69 |
- <uri link="#aclall">Is it possible to use grsecurity, RSBAC, SELinux and |
| 70 |
- PaX all at the same time?</uri> |
| 71 |
- </li> |
| 72 |
- <li> |
| 73 |
- <uri link="#hardenedcflags">Do I need to pass any flags to LDFLAGS/CFLAGS in |
| 74 |
- order to turn on PIE/SSP building?</uri> |
| 75 |
- </li> |
| 76 |
- <li> |
| 77 |
- <uri link="#hardenedcflagsoff">How do I turn off PIE/SSP building?</uri> |
| 78 |
- </li> |
| 79 |
- <li> |
| 80 |
- <uri link="#fsexec">My kernel compilation fails with the error "error: |
| 81 |
- structure has no member named `curr_ip'", how do I fix that?</uri> |
| 82 |
- </li> |
| 83 |
- <li> |
| 84 |
- <uri link="#hardenedproject">I just found out about the hardened project; do |
| 85 |
- I have to install everything on the project page in order to install |
| 86 |
- Hardened Gentoo?</uri> |
| 87 |
- </li> |
| 88 |
- <li> |
| 89 |
- <uri link="#Othreessp">Why don't my programs work when I use CFLAGS="-O3" |
| 90 |
- and hardened gcc?</uri> |
| 91 |
- </li> |
| 92 |
- <li> |
| 93 |
- <uri link="#cascadebootstrap">What happened to bootstrap-cascade.sh?</uri> |
| 94 |
- </li> |
| 95 |
- <li> |
| 96 |
- <uri link="#hardenedprofile">How do I switch to the hardened profile?</uri> |
| 97 |
- </li> |
| 98 |
- <li> |
| 99 |
- <uri link="#hardeneddebug">How do I debug with gdb?</uri> |
| 100 |
- </li> |
| 101 |
-</ul> |
| 102 |
- |
| 103 |
-</body> |
| 104 |
-</section> |
| 105 |
- |
| 106 |
-<section> |
| 107 |
-<title>PaX</title> |
| 108 |
-<body> |
| 109 |
- |
| 110 |
-<ul> |
| 111 |
- <li> |
| 112 |
- <uri link="#paxinformation">What is the homepage for PaX?</uri> |
| 113 |
- </li> |
| 114 |
- <li> |
| 115 |
- <uri link="#paxgentoodoc">What Gentoo documentation exists about PaX?</uri> |
| 116 |
- </li> |
| 117 |
- <li> |
| 118 |
- <uri link="#paxnoelf">I keep getting the message: "error while loading |
| 119 |
- shared libraries: cannot make segment writable for relocation: Permission |
| 120 |
- denied." What does this mean? </uri> |
| 121 |
- </li> |
| 122 |
- <li> |
| 123 |
- <uri link="#paxjava">Ever since I started using PaX I can't get Java |
| 124 |
- working, why?</uri> |
| 125 |
- </li> |
| 126 |
-</ul> |
| 127 |
- |
| 128 |
-</body> |
| 129 |
-</section> |
| 130 |
- |
| 131 |
-<section> |
| 132 |
-<title>grsecurity</title> |
| 133 |
+<title>Introduction</title> |
| 134 |
<body> |
| 135 |
|
| 136 |
-<ul> |
| 137 |
- <li> |
| 138 |
- <uri link="#grsecinformation">What is the homepage for grsecurity?</uri> |
| 139 |
- </li> |
| 140 |
- <li> |
| 141 |
- <uri link="#grsecgentoodoc">What Gentoo documentation exists about |
| 142 |
- grsecurity?</uri> |
| 143 |
- </li> |
| 144 |
- <li> |
| 145 |
- <uri link="#grsec2681">Can I use grsecurity with a 2.6.8, 2.6.8.1, or 2.6.9 |
| 146 |
- kernel?</uri> |
| 147 |
- </li> |
| 148 |
-</ul> |
| 149 |
- |
| 150 |
-</body> |
| 151 |
-</section> |
| 152 |
- |
| 153 |
-<section> |
| 154 |
-<title>RSBAC</title> |
| 155 |
-<body> |
| 156 |
- |
| 157 |
-<ul> |
| 158 |
- <li> |
| 159 |
- <uri link="#rsbacinformation">What is the homepage for RSBAC?</uri> |
| 160 |
- </li> |
| 161 |
- <li> |
| 162 |
- <uri link="#rsbacgentoodoc">What Gentoo documentation exists about |
| 163 |
- RSBAC?</uri> |
| 164 |
- </li> |
| 165 |
- <li> |
| 166 |
- <uri link="#rsbacinitrd">How do I use an initial ramdisk with a RSBAC |
| 167 |
- enabled kernel?</uri> |
| 168 |
- </li> |
| 169 |
-</ul> |
| 170 |
- |
| 171 |
-</body> |
| 172 |
-</section> |
| 173 |
- |
| 174 |
-<section> |
| 175 |
-<title>SELinux</title> |
| 176 |
-<body> |
| 177 |
- |
| 178 |
-<ul> |
| 179 |
- <li> |
| 180 |
- <uri link="#selinuxfaq">Where can I find SELinux related frequently asked |
| 181 |
- questions?</uri> |
| 182 |
- </li> |
| 183 |
-</ul> |
| 184 |
+<p> |
| 185 |
+The following is a collection of questions collected from #gentoo-hardened IRC |
| 186 |
+channel and the gentoo-hardened mailing list. As such, is geared towards |
| 187 |
+answering fast and concisely rather than providing a whole insight on the |
| 188 |
+technologies behind Gentoo Hardened. It is advisable reading the rest of the |
| 189 |
+documentation on the Gentoo Hardened Project page and that on the projects' |
| 190 |
+home pages in order to get a better insight. |
| 191 |
+</p> |
| 192 |
|
| 193 |
</body> |
| 194 |
</section> |
| 195 |
-</chapter> |
| 196 |
+</faqindex> |
| 197 |
|
| 198 |
<chapter> |
| 199 |
<title>General Questions</title> |
| 200 |
@@ -175,96 +70,125 @@ |
| 201 |
</section> |
| 202 |
|
| 203 |
<section id="whichisbetter"> |
| 204 |
-<title>What should I use: grsecurity, RSBAC or SELinux?</title> |
| 205 |
+<title>What should I use: Grsecurity's RBAC or SELinux?</title> |
| 206 |
<body> |
| 207 |
|
| 208 |
<p> |
| 209 |
-The answer to this question is highly subjective, so the hardened Gentoo project |
| 210 |
-simply tries to lay out each technology and leave the choice up to the user. |
| 211 |
-This decision requires a lot of research that we have hopefully provided clearly |
| 212 |
-in the hardened documentation. However, if you have any specific questions |
| 213 |
-about the security model that each provides, feel free to question the relevant |
| 214 |
-developer in our IRC channel or on the mailing list. |
| 215 |
+The answer to this question is highly subjective, and very dependent on your |
| 216 |
+requisites so the hardened Gentoo project simply tries to lay out each |
| 217 |
+technology and leave the choice up to the user. This decision requires a lot of |
| 218 |
+research that we have hopefully provided clearly in the hardened documentation. |
| 219 |
+However, if you have any specific questions about the security model that each |
| 220 |
+provides, feel free to question the relevant developer in our IRC channel or on |
| 221 |
+the mailing list. |
| 222 |
</p> |
| 223 |
|
| 224 |
</body> |
| 225 |
</section> |
| 226 |
|
| 227 |
<section id="aclall"> |
| 228 |
-<title>Is it possible to use grsecurity, RSBAC, SELinux and PaX all at the same |
| 229 |
+<title>Is it possible to use Grsecurity, SELinux and PaX all at the same |
| 230 |
time?</title> |
| 231 |
<body> |
| 232 |
|
| 233 |
<p> |
| 234 |
-Yes, this combination is quite possible as PaX works with grsecurity, RSBAC |
| 235 |
-and SELinux. The only conflict that arises is you can only use one access |
| 236 |
-control system. |
| 237 |
+Yes, this combination is quite possible as PaX and some of Grsecurity's features |
| 238 |
+work with Grsecurity's RBAC and SELinux. The only conflict that arises is you |
| 239 |
+can only use one access control system (be it RBAC or SELinux). |
| 240 |
</p> |
| 241 |
|
| 242 |
</body> |
| 243 |
</section> |
| 244 |
|
| 245 |
<section id="hardenedcflags"> |
| 246 |
-<title>Do I need to pass any flags to LDFLAGS/CFLAGS in order to turn on PIE/SSP |
| 247 |
-building?</title> |
| 248 |
+<title>Do I need to pass any flags to LDFLAGS/CFLAGS in order to turn on |
| 249 |
+hardened building?</title> |
| 250 |
<body> |
| 251 |
|
| 252 |
<p> |
| 253 |
No, the current toolchain implements the equivalent of <c>CFLAGS="-fPIE |
| 254 |
--fstack-protector-all" LDFLAGS="-Wl,-z,now -Wl,-z,relro"</c> automatically |
| 255 |
-through GCC's specfile which is a more proper solution. For older hardened-gcc |
| 256 |
-users, add <c>USE="hardened pic"</c> to your <path>/etc/make.conf</path> and |
| 257 |
-then upgrade with the following commands: |
| 258 |
+-fstack-protector-all -D_FORTIFY_SOURCE=2" LDFLAGS="-Wl,-z,now -Wl,-z,relro"</c> |
| 259 |
+automatically through GCC's built-in spec and using the specfiles to disable |
| 260 |
+them which is a more proper solution. For older hardened-gcc users the best |
| 261 |
+approach is switch to the hardened profile and then upgrade following the steps |
| 262 |
+on the <uri link="#hardenedprofile">How to switch to Gentoo Hardened question |
| 263 |
+</uri> |
| 264 |
</p> |
| 265 |
|
| 266 |
-<pre caption="Hardened Toolchain Installation"> |
| 267 |
-# <i>emerge --oneshot binutils gcc virtual/libc</i> |
| 268 |
-# <i>emerge -e world</i> |
| 269 |
-</pre> |
| 270 |
+<note> |
| 271 |
+Manually enabling the hardening flags it is not recommended at all. |
| 272 |
+</note> |
| 273 |
+ |
| 274 |
+<note> |
| 275 |
+Sending a -fno... flag will disable the flag, also -fstack-protector-all and |
| 276 |
+-fstack-protector may interfere when passed directly. |
| 277 |
+</note> |
| 278 |
|
| 279 |
<note> |
| 280 |
-Gentoo patches its GCCs to allow specfiles to be passed |
| 281 |
-through an environment variable. Currently several sets of specfiles are |
| 282 |
-installed on Gentoo systems that allow users on supported architectures |
| 283 |
-to easily switch the functionality off and on of the toolchain. |
| 284 |
-To access the specs as the end user you can use the gcc-config utility. |
| 285 |
+Gentoo patches its GCCs to allow specfiles to be passed through an environment |
| 286 |
+variable. Currently several sets of specfiles are installed on Gentoo systems |
| 287 |
+that allow users on supported architectures to easily switch the functionality |
| 288 |
+off and on of the toolchain. To access the specs as the end user you can use the |
| 289 |
+<c>gcc-config</c> utility. |
| 290 |
</note> |
| 291 |
|
| 292 |
</body> |
| 293 |
</section> |
| 294 |
|
| 295 |
<section id="hardenedcflagsoff"> |
| 296 |
-<title>How do I turn off PIE/SSP building?</title> |
| 297 |
+<title>How do I turn off hardened building?</title> |
| 298 |
<body> |
| 299 |
|
| 300 |
<p> |
| 301 |
You can use <c>gcc-config</c> to accomplish this: |
| 302 |
</p> |
| 303 |
- |
| 304 |
<pre caption="Example gcc-config output"> |
| 305 |
-# gcc-config -l |
| 306 |
- [1] i686-pc-linux-gnu-3.4.4 * |
| 307 |
- [2] i686-pc-linux-gnu-3.4.4-hardenednopie |
| 308 |
- [3] i686-pc-linux-gnu-3.4.4-hardenednopiessp |
| 309 |
- [4] i686-pc-linux-gnu-3.4.4-hardenednossp |
| 310 |
- [5] i686-pc-linux-gnu-3.4.4-vanilla |
| 311 |
+# gcc-config -l |
| 312 |
+ [1] x86_64-pc-linux-gnu-4.4.4 * |
| 313 |
+ [2] x86_64-pc-linux-gnu-4.4.4-hardenednopie |
| 314 |
+ [3] x86_64-pc-linux-gnu-4.4.4-hardenednopiessp |
| 315 |
+ [4] x86_64-pc-linux-gnu-4.4.4-hardenednossp |
| 316 |
+ [5] x86_64-pc-linux-gnu-4.4.4-vanilla |
| 317 |
|
| 318 |
+<comment>To turn off PIE building switch to the hardenednopie profile:</comment> |
| 319 |
+# gcc-config x86_64-pc-linux-gnu-4.4.4-hardenednopie |
| 320 |
<comment>To turn off SSP building switch to the hardenednossp profile:</comment> |
| 321 |
-# gcc-config i686-pc-linux-gnu-3.4.4-hardenednossp |
| 322 |
+# gcc-config x86_64-pc-linux-gnu-4.4.4-hardenednossp |
| 323 |
+<comment>To turn off SSP and PIE building switch to the hardenednopiessp profile:</comment> |
| 324 |
+# gcc-config x86_64-pc-linux-gnu-4.4.4-hardenednopiessp |
| 325 |
+<comment>To turn off all hardened building switch to the vanilla profile:</comment> |
| 326 |
+# gcc-config x86_64-pc-linux-gnu-4.4.4-vanilla |
| 327 |
</pre> |
| 328 |
|
| 329 |
+<note> |
| 330 |
+The previous output will vary according to the gcc version and architecture you |
| 331 |
+use, also the commands required to disable things will vary depending on the |
| 332 |
+output of the first command. |
| 333 |
+</note> |
| 334 |
+ |
| 335 |
<p> |
| 336 |
Alternatively you can achieve the same by changing your CFLAGS: |
| 337 |
</p> |
| 338 |
|
| 339 |
+<impo> |
| 340 |
+Disabling flags manually is not recommended by the team and thus an unsupported |
| 341 |
+option, do this at your own risk. |
| 342 |
+</impo> |
| 343 |
+ |
| 344 |
+ |
| 345 |
<p> |
| 346 |
To turn off default SSP building when using the hardened toolchain, append |
| 347 |
-<c>-fno-stack-protector-all -fno-stack-protector</c> to your CFLAGS. |
| 348 |
+<c>-fno-stack-protector</c> to your CFLAGS. |
| 349 |
</p> |
| 350 |
+<note> |
| 351 |
+On gcc 3.4 releases you need to use <c>-fno-stack-protector-all |
| 352 |
+-fno-stack-protector</c> |
| 353 |
+</note> |
| 354 |
|
| 355 |
<p> |
| 356 |
If you want to turn off default PIE building then append <c>-nopie</c> to your |
| 357 |
-<c>CFLAGS</c>. |
| 358 |
+<c>CFLAGS</c> and your <c>LDFLAGS</c> (as LDFLAGS is used with no CFLAGS when |
| 359 |
+using gcc to link thre object files). |
| 360 |
</p> |
| 361 |
|
| 362 |
<impo> |
| 363 |
@@ -273,25 +197,28 @@ |
| 364 |
behavior which should be the intended result. |
| 365 |
</impo> |
| 366 |
|
| 367 |
-<note> |
| 368 |
-If you are interested in using per-package CFLAGS with Portage currently then |
| 369 |
-you may be interested in reading about the script solar has developed to deal |
| 370 |
-with this: <uri>http://article.gmane.org/gmane.linux.gentoo.hardened/1204</uri> |
| 371 |
-</note> |
| 372 |
- |
| 373 |
-</body> |
| 374 |
-</section> |
| 375 |
- |
| 376 |
-<section id="fsexec"> |
| 377 |
-<title>My kernel compilation fails with the error "error: structure has no |
| 378 |
-member named `curr_ip'", how do I fix that?</title> |
| 379 |
-<body> |
| 380 |
+<p> |
| 381 |
+If you want to turn off default now binding append <c>-z,lazy</c> to your |
| 382 |
+<c>LDFLAGS</c>. |
| 383 |
+</p> |
| 384 |
|
| 385 |
<p> |
| 386 |
-In order to use PaX on hardened-sources, you must enable grsecurity as well in |
| 387 |
-your kernel config. This should be fixed in a future kernels. |
| 388 |
+If you want to turn off default relro binding append <c>-z,norelro</c> to your |
| 389 |
+<c>LDFLAGS</c>. |
| 390 |
</p> |
| 391 |
|
| 392 |
+<note> |
| 393 |
+Relro is default on binutils so be sure that you want to disable it before doing |
| 394 |
+so. |
| 395 |
+</note> |
| 396 |
+ |
| 397 |
+<note> |
| 398 |
+If you are interested in using per-package CFLAGS with Portage currently then |
| 399 |
+you may be interested in reading about <uri |
| 400 |
+link="http://article.gmane.org/gmane.linux.gentoo.hardened/1204">the script |
| 401 |
+solar has developed to deal with this</uri> |
| 402 |
+</note> |
| 403 |
+ |
| 404 |
</body> |
| 405 |
</section> |
| 406 |
|
| 407 |
@@ -317,30 +244,27 @@ |
| 408 |
|
| 409 |
<p> |
| 410 |
Using the gcc optimization flag <c>-O3</c> has been known to be problematic with |
| 411 |
-stack-smashing protector (SSP) in some situations. This optimization flag is not |
| 412 |
-officially supported and therefore discouraged by the hardened team. Compile |
| 413 |
-issues where a user uses <c>CFLAGS="-O3"</c> will be closed as INVALID/CANTFIX |
| 414 |
-and or ignored. |
| 415 |
+stack-smashing protector (SSP) and on vanilla builds in some situations. This |
| 416 |
+optimization flag is not officially supported and is, therefore, discouraged by |
| 417 |
+the hardened team. Compile issues where a user uses <c>CFLAGS="-O3"</c> may be |
| 418 |
+closed as INVALID/CANTFIX and/or ignored. |
| 419 |
</p> |
| 420 |
|
| 421 |
</body> |
| 422 |
</section> |
| 423 |
|
| 424 |
-<section id="cascadebootstrap"> |
| 425 |
-<title>What happened to bootstrap-cascade.sh?</title> |
| 426 |
+<section id="hardenedprofile"> |
| 427 |
+<title>How do I switch to the hardened profile?</title> |
| 428 |
<body> |
| 429 |
- |
| 430 |
<p> |
| 431 |
-Recently, the old bootstrap.sh and bootstrap-2.6.sh were deprecated. In their |
| 432 |
-place, bootstrap-cascade.sh has been renamed to bootstrap.sh. |
| 433 |
+To change your profile use eselect to choose it. |
| 434 |
</p> |
| 435 |
|
| 436 |
-</body> |
| 437 |
-</section> |
| 438 |
- |
| 439 |
-<section id="hardenedprofile"> |
| 440 |
-<title>How do I switch to the hardened profile?</title> |
| 441 |
-<body> |
| 442 |
+<note> |
| 443 |
+Reading part 1 chapter 6 "Installing the Gentoo BaseSystem" on the |
| 444 |
+<uri link="/doc/en/handbook/">Gentoo Handbook</uri> is recommended for better |
| 445 |
+instructions on how to change your profile. |
| 446 |
+</note> |
| 447 |
|
| 448 |
<pre caption="Set make.profile"> |
| 449 |
# <i>eselect profile list</i> |
| 450 |
@@ -351,8 +275,8 @@ |
| 451 |
[5] default/linux/amd64/10.0/developer |
| 452 |
[6] default/linux/amd64/10.0/no-multilib |
| 453 |
[7] default/linux/amd64/10.0/server |
| 454 |
-[8] hardened/linux/amd64/10.0 |
| 455 |
-[9] hardened/linux/amd64/10.0/no-multilib |
| 456 |
+[8] hardened/linux/amd64 |
| 457 |
+[9] hardened/linux/amd64/no-multilib |
| 458 |
[10] selinux/2007.0/amd64 |
| 459 |
[11] selinux/2007.0/amd64/hardened |
| 460 |
[12] selinux/v2refpolicy/amd64 |
| 461 |
@@ -363,66 +287,124 @@ |
| 462 |
# <i>eselect profile set 8</i> <comment>(replace 8 with the desired hardened profile)</comment> |
| 463 |
</pre> |
| 464 |
|
| 465 |
+<note> |
| 466 |
+The previous output will vary according to the architecture you use, also the |
| 467 |
+commands required to choose the profile will vary depending on the output of the |
| 468 |
+first command. |
| 469 |
+</note> |
| 470 |
+ |
| 471 |
<p> |
| 472 |
-After setting up your profile, you should recompile your system using a |
| 473 |
-hardened toolchain so that you have a consistent base: |
| 474 |
+After setting up your profile, you should recompile your system using a hardened |
| 475 |
+toolchain so that you have a consistent base: |
| 476 |
</p> |
| 477 |
|
| 478 |
<pre caption="Switch to hardened toolchain"> |
| 479 |
# <i>emerge --oneshot binutils gcc virtual/libc</i> |
| 480 |
-# <i>emerge -e world</i> |
| 481 |
+# <i>emerge -e --keep-going system</i> |
| 482 |
+# <i>emerge -e --keep-going world</i> |
| 483 |
</pre> |
| 484 |
|
| 485 |
+<p> |
| 486 |
+The <c>--keep-going</c> option is added to ensure emerge won't stop in case any |
| 487 |
+package fails to build. |
| 488 |
+</p> |
| 489 |
+ |
| 490 |
</body> |
| 491 |
</section> |
| 492 |
|
| 493 |
<section id="hardeneddebug"> |
| 494 |
<title>How do I debug with gdb?</title> |
| 495 |
<body> |
| 496 |
+ |
| 497 |
<p> |
| 498 |
-First gotcha is that GDB can't resolve symbols in PIEs; it doesn't realise that |
| 499 |
-the addresses are relative in PIEs not absolute. This shows up when you try to |
| 500 |
-get a backtrace for example, and see a stream of lines with '??' where the |
| 501 |
-symbol should be. |
| 502 |
+We have written a <uri link="/proj/en/hardened/hardened-debugging.xml">document |
| 503 |
+on how to debug with Gentoo Hardened</uri>, so following the recommendations |
| 504 |
+there should fix your problem. |
| 505 |
</p> |
| 506 |
+ |
| 507 |
+</body> |
| 508 |
+</section> |
| 509 |
+ |
| 510 |
+<section id="jitflag"> |
| 511 |
+<title>Why is the jit flag disabled in the hardened profile?</title> |
| 512 |
+<body> |
| 513 |
+ |
| 514 |
<p> |
| 515 |
-To get around this, do the final link stage with <c>-nopie</c> - all the |
| 516 |
-preceding object compilations can still be with <c>-fPIE</c> as normal (i.e. the |
| 517 |
-default with the hardened compiler) so that your executable is as close as |
| 518 |
-possible to the real thing, but the final link must create a regular executable. |
| 519 |
-Try adding <c>-nopie</c> to LDFLAGS if you're building with emerge. |
| 520 |
+JIT means Just In Time Compilation and consist on taking some code meant to be |
| 521 |
+interpreted (like Java bytecode or JavaScript code) compile it into native |
| 522 |
+binary code in memory and then executing the compiled code. This means that the |
| 523 |
+program need a section of memory which has write and execution permissions to |
| 524 |
+write and then execute the code which is denied by PaX, unless the mprotect flag |
| 525 |
+is unset for the executable. As a result, we disabled the JIT use flag by |
| 526 |
+default to avoid complaints and security problems. |
| 527 |
</p> |
| 528 |
+ |
| 529 |
<p> |
| 530 |
-Another way of accomplishing this, it to emerge >=sys-devel/gdb-7.1, which contains |
| 531 |
-a special patch that makes it able to debug executeables linked with -pie. |
| 532 |
+You should bear in mind that having a section which is written and then executed |
| 533 |
+can be a serious security problem as the attacker needs to be able to exploit a |
| 534 |
+bug between the write and execute stages to write in that section in order to |
| 535 |
+execute any code it wants to. |
| 536 |
</p> |
| 537 |
+</body> |
| 538 |
+</section> |
| 539 |
+ |
| 540 |
+<section id="enablejit"> |
| 541 |
+<title>How do I enable the jit flag?</title> |
| 542 |
+<body> |
| 543 |
+ |
| 544 |
<p> |
| 545 |
-The second gotcha is that PaX may prevent GDB from setting breakpoints, |
| 546 |
-depending on how the kernel is configured. This includes the breakpoint at main |
| 547 |
-which you need to get started. To stop PaX doing this, the executable being |
| 548 |
-debugged needs the <c>m</c> and <c>x</c> flags. The <c>x</c> flag is set by |
| 549 |
-default, so it is enough to do: |
| 550 |
+If you need it, we recommend enabling the flag in a per package basis using |
| 551 |
+<c>/etc/portage/package.use</c> |
| 552 |
</p> |
| 553 |
-<pre caption="Relax PaX for debug"> |
| 554 |
-# <i>/sbin/paxctl -m foo</i> |
| 555 |
+ |
| 556 |
+<pre caption="Example /etc/portage/package.use enabling JIT in some libraries"> |
| 557 |
+x11-libs/qt-core jit |
| 558 |
+x11-libs/qt-script jit |
| 559 |
+x11-libs/qt-webkit jit |
| 560 |
</pre> |
| 561 |
+ |
| 562 |
<p> |
| 563 |
-At this point, you should be good to go! Fire up gdb in the usual way. Good |
| 564 |
-luck! |
| 565 |
+Anyway, you can enable the use flag globally using <c>/etc/make.conf</c> |
| 566 |
</p> |
| 567 |
+ |
| 568 |
+<pre caption="Example /etc/make.conf with JIT enabled"> |
| 569 |
+CFLAGS="-O2 -pipe -fomit-frame-pointer -march=native" |
| 570 |
+CXXFLAGS="${CFLAGS}" |
| 571 |
+# WARNING: Changing your CHOST is not something that should be done lightly. |
| 572 |
+# Please consult http://www.gentoo.org/doc/en/change-chost.xml before changing. |
| 573 |
+CHOST="x86_64-pc-linux-gnu" |
| 574 |
+# These are the USE flags that were used in addition to what is provided by the |
| 575 |
+# profile used for building. |
| 576 |
+<comment>#If you have more uses adding jit to the end should suffice</comment> |
| 577 |
+USE="jit" |
| 578 |
+ |
| 579 |
+MAKEOPTS="-j2" |
| 580 |
+ |
| 581 |
+GENTOO_MIRRORS="ftp://ftp.udc.es/gentoo/" |
| 582 |
+ |
| 583 |
+SYNC="rsync://rsync.europe.gentoo.org/gentoo-portage" |
| 584 |
+</pre> |
| 585 |
+ |
| 586 |
+<impo> |
| 587 |
+Remember that if you enable JIT code on PaX you may need to disable mprotect on |
| 588 |
+the binaries using such code, either by them selves or through libraries. Check |
| 589 |
+the <uri link="#paxjavajit">PaX question on Java and JIT to see how to do this |
| 590 |
+</uri> |
| 591 |
+</impo> |
| 592 |
+ |
| 593 |
</body> |
| 594 |
</section> |
| 595 |
- |
| 596 |
+ |
| 597 |
</chapter> |
| 598 |
|
| 599 |
<chapter> |
| 600 |
<title>PaX Questions</title> |
| 601 |
<section id="paxinformation"> |
| 602 |
-<title>What is the homepage for PaX?</title> |
| 603 |
+<title>Where is the homepage for PaX?</title> |
| 604 |
<body> |
| 605 |
|
| 606 |
<p> |
| 607 |
-The homepage for PaX is located at <uri>http://pax.grsecurity.net</uri>. |
| 608 |
+That is <uri link="http://pax.grsecurity.net">the homepage for PaX</uri>. |
| 609 |
</p> |
| 610 |
|
| 611 |
</body> |
| 612 |
@@ -433,14 +415,45 @@ |
| 613 |
<body> |
| 614 |
|
| 615 |
<p> |
| 616 |
-Currently the only Gentoo documentation that exists about PaX is a PaX |
| 617 |
-quickstart guide located at the |
| 618 |
-<uri>http://www.gentoo.org/proj/en/hardened/pax-quickstart.xml</uri> website. |
| 619 |
+Currently the only Gentoo documentation that exists about PaX is a <uri |
| 620 |
+link="http://www.gentoo.org/proj/en/hardened/pax-quickstart.xml"> PaX quickstart |
| 621 |
+guide</uri>. |
| 622 |
</p> |
| 623 |
|
| 624 |
</body> |
| 625 |
</section> |
| 626 |
|
| 627 |
+<section id="paxmarkings"> |
| 628 |
+<title>How do PaX markings work?</title> |
| 629 |
+<body> |
| 630 |
+ |
| 631 |
+<p> |
| 632 |
+PaX markings are a way to tell PaX which features should enable (or disable) for |
| 633 |
+a certain binary. |
| 634 |
+</p> |
| 635 |
+ |
| 636 |
+<p> |
| 637 |
+Features can either be enabled, disabled or not set. Enabling or disabling them |
| 638 |
+will supersede the kernel action, so a binary with a feature enabled will |
| 639 |
+always use the feature and one with a feature disabled won't ever used it. |
| 640 |
+</p> |
| 641 |
+ |
| 642 |
+<p> |
| 643 |
+When the feature status is not set the kernel will choose whether to enable or |
| 644 |
+disable it. By default, the hardened kernel will enable those features with only |
| 645 |
+two exceptions, the feature is not supported by the architecture/kernel or PaX |
| 646 |
+is running in Soft Mode. In those two cases, it will be disabled. |
| 647 |
+</p> |
| 648 |
+ |
| 649 |
+<note> |
| 650 |
+In order to have Soft Mode, your kernel should have that feature enabled and |
| 651 |
+you should enable it either passing <c>pax_softmode=1</c> in the kernel cmdline |
| 652 |
+or setting to 1 the option in <c>/proc/sys/kernel/pax/softmode</c>. |
| 653 |
+</note> |
| 654 |
+ |
| 655 |
+</body> |
| 656 |
+</section> |
| 657 |
+ |
| 658 |
<section id="paxnoelf"> |
| 659 |
<title>I keep getting the message: "error while loading shared libraries: cannot |
| 660 |
make segment writable for relocation: Permission denied." What does this |
| 661 |
@@ -448,13 +461,29 @@ |
| 662 |
<body> |
| 663 |
|
| 664 |
<p> |
| 665 |
-This error occurs when you enable CONFIG_PAX_NOELFRELOCS as such: |
| 666 |
+Text relocations are a way in which references in the executable code to |
| 667 |
+addresses not known at link time are solved. Basically they just write the |
| 668 |
+appropriate address at runtime marking the code segment writable in order to |
| 669 |
+change the address then unmarking it. This can be a problem as an attacker could |
| 670 |
+try to exploit a bug when the text relocation happens in order to be able to |
| 671 |
+write arbitrary code in the text segment which would be executed. As this also |
| 672 |
+means that code will be loaded on fixed addresses (not be position independent) |
| 673 |
+this can also be exploited to pass over the randomization features provided by |
| 674 |
+PaX.</p> |
| 675 |
+ |
| 676 |
+<p> |
| 677 |
+As this can be triggered for example by adding a library with text |
| 678 |
+relocations to the ones loaded by the executable, PaX offers the option |
| 679 |
+CONFIG_PAX_NOELFRELOCS in order to avoid them. This option is enabled like this: |
| 680 |
</p> |
| 681 |
|
| 682 |
<pre caption="Menuconfig Options"> |
| 683 |
-Non-executable page -> |
| 684 |
- |
| 685 |
- [*] Disallow ELF text relocations |
| 686 |
+-> Security options |
| 687 |
+ -> PaX |
| 688 |
+ -> Enable various PaX features |
| 689 |
+ -> Non-executable pages |
| 690 |
+ [*] Restrict mprotect() |
| 691 |
+ [*] Allow ELF text relocations |
| 692 |
</pre> |
| 693 |
|
| 694 |
<p> |
| 695 |
@@ -490,87 +519,87 @@ |
| 696 |
</body> |
| 697 |
</section> |
| 698 |
|
| 699 |
-<section id="paxjava"> |
| 700 |
-<title>Ever since I started using PaX I can't get Java working, why?</title> |
| 701 |
+<section id="paxjavajit"> |
| 702 |
+<title>Ever since I started using PaX I can't get Java/JIT code working, |
| 703 |
+why?</title> |
| 704 |
<body> |
| 705 |
|
| 706 |
<p> |
| 707 |
As part of its design, the Java virtual machine creates a considerable amount of |
| 708 |
-code at runtime which does not make PaX happy. There are two ways to correct |
| 709 |
-this problem: |
| 710 |
+code at runtime which does not make PaX happy. Although, with current versions |
| 711 |
+of portage and java, portage will mark the binaries automatically, you still |
| 712 |
+need to enable PaX marking so PaX can do an exception with them and have paxctl |
| 713 |
+installed so the markings can be applied to the binaries (an reemerge them so |
| 714 |
+they are applied). |
| 715 |
</p> |
| 716 |
|
| 717 |
-<pre caption="Install Chpax"> |
| 718 |
-# <i>emerge chpax</i> |
| 719 |
-# <i>/etc/init.d/chpax start</i> |
| 720 |
+<p> |
| 721 |
+This of course can't be applied to all packages linking with libraries with JIT |
| 722 |
+code, so if it doesn't, there are two ways to correct this problem: |
| 723 |
+</p> |
| 724 |
+ |
| 725 |
+<pre caption="Enable the marking on your kernel"> |
| 726 |
+-> Security options |
| 727 |
+ -> PaX |
| 728 |
+ -> Enable various PaX features |
| 729 |
+ -> PaX Control |
| 730 |
+ [*] Use ELF program header marking |
| 731 |
+</pre> |
| 732 |
+ |
| 733 |
+<pre caption="Install paxctl"> |
| 734 |
+# <i>emerge paxctl</i> |
| 735 |
</pre> |
| 736 |
|
| 737 |
<p> |
| 738 |
-Or if you already have <c>chpax</c> emerged then you can do: |
| 739 |
+When you already have <c>paxctl</c> emerged you can do: |
| 740 |
</p> |
| 741 |
|
| 742 |
-<pre caption="Java Chpax Options"> |
| 743 |
-# <i>chpax -pemrxs /opt/*-jdk-*/{jre,}/bin/*</i> |
| 744 |
+<pre caption="Disable PaX for the binary"> |
| 745 |
+# <i>paxctl -pemrxs /path/to/binary</i> |
| 746 |
</pre> |
| 747 |
|
| 748 |
<p> |
| 749 |
-Both of these options will slightly modify the ELF eheader in order to correctly |
| 750 |
+This option will slightly modify the ELF header in order to correctly |
| 751 |
set the PAX flags on the binaries. |
| 752 |
</p> |
| 753 |
|
| 754 |
<note> |
| 755 |
If you are running PaX in conjunction with an additional security implementation |
| 756 |
-such as RSBAC, grsecurity, or SELinux you should manage PaX using the kernel |
| 757 |
+such as Grsecurity's RBAC, or SELinux you should manage PaX using the kernel |
| 758 |
hooks provided for each implementation. |
| 759 |
</note> |
| 760 |
|
| 761 |
<p> |
| 762 |
-On RSBAC, you can label all Java files with the following command. |
| 763 |
+The other way is using your security implementation to do this using the kernel |
| 764 |
+hooks. |
| 765 |
</p> |
| 766 |
|
| 767 |
-<pre caption="Java PaX options with RSBAC"> |
| 768 |
-# <i>for i in $(ls /opt/*(jdk|sdk)*/{jre,}/bin/*);do attr_set_file_dir FILE $i pax_flags pmerxs;done</i> |
| 769 |
-</pre> |
| 770 |
- |
| 771 |
</body> |
| 772 |
</section> |
| 773 |
-</chapter> |
| 774 |
|
| 775 |
-<chapter> |
| 776 |
-<title>grsecurity Questions</title> |
| 777 |
-<section id="grsecinformation"> |
| 778 |
-<title>What is the homepage for grsecurity?</title> |
| 779 |
+<section id="paxbootparams"> |
| 780 |
+<title>Can I disable PaX features at boot?</title> |
| 781 |
<body> |
| 782 |
|
| 783 |
<p> |
| 784 |
-The homepage for grsecurity is located at <uri>http://www.grsecurity.net</uri>. |
| 785 |
+Although this is not advised except when used to rescue the system or for |
| 786 |
+debugging purposes, it is possible to change a few of PaX behaviours on boot via |
| 787 |
+the kernel command line. |
| 788 |
</p> |
| 789 |
|
| 790 |
-</body> |
| 791 |
-</section> |
| 792 |
- |
| 793 |
-<section id="grsecgentoodoc"> |
| 794 |
-<title>What Gentoo documentation exists about grsecurity?</title> |
| 795 |
-<body> |
| 796 |
- |
| 797 |
<p> |
| 798 |
-The most current documentation for grsecurity is a Grsecurity2 quickstart guide |
| 799 |
-located at <uri>http://www.gentoo.org/proj/en/hardened/grsecurity.xml</uri>. |
| 800 |
+Passing <c>pax_nouderef</c> in the kernel cmdline will disable uderef which can |
| 801 |
+cause problems on certain virtualization environments and cause some bugs (at |
| 802 |
+times) at the expense leaving the kernel unprotected against unwanted userspace |
| 803 |
+dereferences. |
| 804 |
</p> |
| 805 |
|
| 806 |
-</body> |
| 807 |
-</section> |
| 808 |
- |
| 809 |
-<section id="grsec2681"> |
| 810 |
-<title>Can I use grsecurity with a 2.6.8, 2.6.8.1, or 2.6.9 kernel?</title> |
| 811 |
-<body> |
| 812 |
- |
| 813 |
<p> |
| 814 |
-Due to significant changes in the 2.6.8 kernel that broke PaX, neither a PaX nor |
| 815 |
-a grsecurity patch are available for kernels 2.6.8, 2.6.8.1, or 2.6.9. Although |
| 816 |
-an experimental patch is available for 2.6.10, the official stance of the PaX |
| 817 |
-Team regarding 2.6 kernels should be noted and taken into consideration before |
| 818 |
-use: <uri> http://forums.grsecurity.net./viewtopic.php?t=968</uri>. |
| 819 |
+Passing <c>pax_softmode=1</c> in the kernel cmdline will enable the softmode |
| 820 |
+which can be useful when booting a not prepared system with a PaX kernel. In |
| 821 |
+soft mode PaX will disable most features by default unless told otherwise via |
| 822 |
+the markings. In a similar way, <c>pax_softmode=0</c> will disable the softmode |
| 823 |
+if it was enabled in the config. |
| 824 |
</p> |
| 825 |
|
| 826 |
</body> |
| 827 |
@@ -578,49 +607,43 @@ |
| 828 |
</chapter> |
| 829 |
|
| 830 |
<chapter> |
| 831 |
-<title>RSBAC Questions</title> |
| 832 |
-<section id="rsbacinformation"> |
| 833 |
-<title>What is the homepage for RSBAC?</title> |
| 834 |
+<title>Grsecurity Questions</title> |
| 835 |
+<section id="grsecinformation"> |
| 836 |
+<title>Where is the homepage for Grsecurity?</title> |
| 837 |
<body> |
| 838 |
|
| 839 |
<p> |
| 840 |
-The homepage for RSBAC is located at <uri>http://www.rsbac.org</uri>. |
| 841 |
+That is the <uri link="http://www.grsecurity.net">homepage for Grsecurity</uri>. |
| 842 |
</p> |
| 843 |
|
| 844 |
</body> |
| 845 |
</section> |
| 846 |
|
| 847 |
-<section id="rsbacgentoodoc"> |
| 848 |
-<title>What Gentoo documentation exists about RSBAC?</title> |
| 849 |
+<section id="grsecgentoodoc"> |
| 850 |
+<title>What Gentoo documentation exists about Grsecurity?</title> |
| 851 |
<body> |
| 852 |
|
| 853 |
<p> |
| 854 |
-All Gentoo RSBAC documentation is located at the RSBAC subproject page found at: |
| 855 |
-<uri>http://www.gentoo.org/proj/en/hardened/rsbac/index.xml</uri> |
| 856 |
-</p> |
| 857 |
- |
| 858 |
-<p> |
| 859 |
-Moreover, non-Gentoo RSBAC documentation can be found in the RSBAC handbook, |
| 860 |
-found at: <uri>http://www.rsbac.org/documentation/rsbac_handbook</uri> |
| 861 |
+The most current documentation for Grsecurity is a <uri |
| 862 |
+link="http://www.gentoo.org/proj/en/hardened/grsecurity.xml">Grsecurity2 |
| 863 |
+quickstart guide</uri>. |
| 864 |
</p> |
| 865 |
|
| 866 |
</body> |
| 867 |
</section> |
| 868 |
|
| 869 |
-<section id="rsbacinitrd"> |
| 870 |
-<title>How do I use an initial ramdisk with a RSBAC enabled kernel?</title> |
| 871 |
+<section id="grsecnew"> |
| 872 |
+<title>Can I use Grsecurity with a recent kernel not on the portage tree |
| 873 |
+</title> |
| 874 |
<body> |
| 875 |
|
| 876 |
<p> |
| 877 |
-To use an initial ramdisk with a RSBAC enabled kernel, a special kernel option |
| 878 |
-must be enabled or else RSBAC will treat the initrd as the root device: |
| 879 |
+Usually we release a new version of hardened sources not long after a new |
| 880 |
+PaX/Grsecurity patch is released, so the best option is just waiting a bit for |
| 881 |
+the kernel team to adapt the patches and then test them. Remind that we won't |
| 882 |
+support kernel sources not coming from the portage tree. |
| 883 |
</p> |
| 884 |
|
| 885 |
-<pre caption="Menuconfig Options"> |
| 886 |
-General RSBAC options ---> |
| 887 |
- [*] Delayed init for initial ramdisk |
| 888 |
-</pre> |
| 889 |
- |
| 890 |
</body> |
| 891 |
</section> |
| 892 |
</chapter> |
| 893 |
@@ -632,8 +655,9 @@ |
| 894 |
<body> |
| 895 |
|
| 896 |
<p> |
| 897 |
-A SELinux specific FAQ can be found at <uri> |
| 898 |
-http://www.gentoo.org/proj/en/hardened/selinux/selinux-handbook.xml?part=3&chap=3</uri>. |
| 899 |
+There is a <uri |
| 900 |
+link="http://www.gentoo.org/proj/en/hardened/selinux/selinux-handbook.xml?part=3&chap=3"> |
| 901 |
+SELinux specific FAQ</uri>. |
| 902 |
</p> |
| 903 |
|
| 904 |
</body> |
Archives