virtio-9p: Security model for symlink and readlink

Mapped mode stores extended attributes in the user space of the extended
attributes. Given that the user space extended attributes are available
to regular files only, special files are created as regular files on the
fileserver and appropriate mode bits are added to the extended attributes.
This method presents all special files and symlinks as regular files on the
fileserver while they are represented as special files on the guest mount.

Implemntation of symlink in mapped security model:

A regular file is created and the link target is written to it.
readlink() reads it back from the file.

On Guest/Client:
lrwxrwxrwx 1 root root 6 2010-05-11 12:20 asymlink -> afile

On Host/Fileserver:
-rw-------. 1 root root 6 2010-05-11 09:20 asymlink
afile

Under passthrough model, it just calls underlying symlink() readlink()
system calls are used.

Under both security models, client user credentials are changed
after the filesystem objec creation.

Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
3 files changed
tree: a6051be7d59bc70cb1bf7af6c11248404dcd9c60
  1. audio/
  2. block/
  3. bsd-user/
  4. darwin-user/
  5. default-configs/
  6. docs/
  7. fpu/
  8. fsdev/
  9. gdb-xml/
  10. hw/
  11. linux-user/
  12. net/
  13. pc-bios/
  14. QMP/
  15. roms/
  16. slirp/
  17. sysconfigs/
  18. target-alpha/
  19. target-arm/
  20. target-cris/
  21. target-i386/
  22. target-m68k/
  23. target-microblaze/
  24. target-mips/
  25. target-ppc/
  26. target-s390x/
  27. target-sh4/
  28. target-sparc/
  29. tcg/
  30. tests/
  31. .gitignore
  32. .gitmodules
  33. a.out.h
  34. acl.c
  35. acl.h
  36. aes.c
  37. aes.h
  38. aio.c
  39. alpha-dis.c
  40. alpha.ld
  41. arch_init.c
  42. arch_init.h
  43. arm-dis.c
  44. arm-semi.c
  45. arm.ld
  46. async.c
  47. balloon.c
  48. balloon.h
  49. block-migration.c
  50. block-migration.h
  51. block.c
  52. block.h
  53. block_int.h
  54. blockdev.c
  55. blockdev.h
  56. bswap.h
  57. bt-host.c
  58. bt-host.h
  59. bt-vhci.c
  60. buffered_file.c
  61. buffered_file.h
  62. cache-utils.c
  63. cache-utils.h
  64. Changelog
  65. check-qdict.c
  66. check-qfloat.c
  67. check-qint.c
  68. check-qjson.c
  69. check-qlist.c
  70. check-qstring.c
  71. cmd.c
  72. cmd.h
  73. cocoa.m
  74. CODING_STYLE
  75. config.h
  76. configure
  77. console.c
  78. console.h
  79. COPYING
  80. COPYING.LIB
  81. cpu-all.h
  82. cpu-common.h
  83. cpu-defs.h
  84. cpu-exec.c
  85. cpus.c
  86. cpus.h
  87. create_config
  88. cris-dis.c
  89. curses.c
  90. curses_keys.h
  91. cursor.c
  92. cursor_hidden.xpm
  93. cursor_left_ptr.xpm
  94. cutils.c
  95. d3des.c
  96. d3des.h
  97. def-helper.h
  98. device_tree.c
  99. device_tree.h
  100. dis-asm.h
  101. disas.c
  102. disas.h
  103. dma-helpers.c
  104. dma.h
  105. dyngen-exec.h
  106. elf.h
  107. envlist.c
  108. envlist.h
  109. exec-all.h
  110. exec.c
  111. feature_to_c.sh
  112. gdbstub.c
  113. gdbstub.h
  114. gen-icount.h
  115. host-utils.c
  116. host-utils.h
  117. hpet.h
  118. hppa-dis.c
  119. hppa.ld
  120. hxtool
  121. i386-dis.c
  122. i386.ld
  123. ia64-dis.c
  124. ia64.ld
  125. input.c
  126. ioport-user.c
  127. ioport.c
  128. ioport.h
  129. iov.c
  130. iov.h
  131. json-lexer.c
  132. json-lexer.h
  133. json-parser.c
  134. json-parser.h
  135. json-streamer.c
  136. json-streamer.h
  137. keymaps.c
  138. keymaps.h
  139. kvm-all.c
  140. kvm-stub.c
  141. kvm.h
  142. libfdt_env.h
  143. LICENSE
  144. linux-aio.c
  145. m68k-dis.c
  146. m68k-semi.c
  147. m68k.ld
  148. MAINTAINERS
  149. Makefile
  150. Makefile.dis
  151. Makefile.hw
  152. Makefile.objs
  153. Makefile.target
  154. Makefile.user
  155. microblaze-dis.c
  156. migration-exec.c
  157. migration-fd.c
  158. migration-tcp.c
  159. migration-unix.c
  160. migration.c
  161. migration.h
  162. mips-dis.c
  163. mips.ld
  164. module.c
  165. module.h
  166. monitor.c
  167. monitor.h
  168. nbd.c
  169. nbd.h
  170. net-checksum.c
  171. net.c
  172. net.h
  173. notify.c
  174. notify.h
  175. os-posix.c
  176. os-win32.c
  177. osdep.c
  178. osdep.h
  179. path.c
  180. pci-ids.txt
  181. poison.h
  182. posix-aio-compat.c
  183. ppc-dis.c
  184. ppc.ld
  185. ppc64.ld
  186. qbool.c
  187. qbool.h
  188. qdict-test-data.txt
  189. qdict.c
  190. qdict.h
  191. qemu-aio.h
  192. qemu-barrier.h
  193. qemu-binfmt-conf.sh
  194. qemu-char.c
  195. qemu-char.h
  196. qemu-common.h
  197. qemu-config.c
  198. qemu-config.h
  199. qemu-doc.texi
  200. qemu-error.c
  201. qemu-error.h
  202. qemu-img-cmds.hx
  203. qemu-img.c
  204. qemu-img.texi
  205. qemu-io.c
  206. qemu-lock.h
  207. qemu-log.h
  208. qemu-malloc.c
  209. qemu-monitor.hx
  210. qemu-nbd.c
  211. qemu-nbd.texi
  212. qemu-objects.h
  213. qemu-option.c
  214. qemu-option.h
  215. qemu-options.h
  216. qemu-options.hx
  217. qemu-os-posix.h
  218. qemu-os-win32.h
  219. qemu-queue.h
  220. qemu-sockets.c
  221. qemu-tech.texi
  222. qemu-thread.c
  223. qemu-thread.h
  224. qemu-timer.c
  225. qemu-timer.h
  226. qemu-tool.c
  227. qemu-x509.h
  228. qemu.sasl
  229. qemu_socket.h
  230. qerror.c
  231. qerror.h
  232. qfloat.c
  233. qfloat.h
  234. qint.c
  235. qint.h
  236. qjson.c
  237. qjson.h
  238. qlist.c
  239. qlist.h
  240. qobject.h
  241. qstring.c
  242. qstring.h
  243. readline.c
  244. readline.h
  245. README
  246. rules.mak
  247. rwhandler.c
  248. rwhandler.h
  249. s390-dis.c
  250. s390.ld
  251. savevm.c
  252. sdl.c
  253. sdl_keysym.h
  254. sdl_zoom.c
  255. sdl_zoom.h
  256. sdl_zoom_template.h
  257. sh4-dis.c
  258. softmmu-semi.h
  259. softmmu_defs.h
  260. softmmu_exec.h
  261. softmmu_header.h
  262. softmmu_template.h
  263. sparc-dis.c
  264. sparc.ld
  265. sparc64.ld
  266. sysemu.h
  267. targphys.h
  268. tcg-runtime.c
  269. texi2pod.pl
  270. thunk.c
  271. thunk.h
  272. TODO
  273. translate-all.c
  274. uboot_image.h
  275. usb-bsd.c
  276. usb-linux.c
  277. usb-stub.c
  278. VERSION
  279. vgafont.h
  280. vl.c
  281. vnc-auth-sasl.c
  282. vnc-auth-sasl.h
  283. vnc-auth-vencrypt.c
  284. vnc-auth-vencrypt.h
  285. vnc-encoding-hextile.c
  286. vnc-encoding-tight.c
  287. vnc-encoding-tight.h
  288. vnc-encoding-zlib.c
  289. vnc-tls.c
  290. vnc-tls.h
  291. vnc.c
  292. vnc.h
  293. vnc_keysym.h
  294. vnchextile.h
  295. x86_64.ld
  296. x_keymap.c
  297. x_keymap.h