On Thu, 2012-02-23 at 21:17 +0100, Sven Vermeulen wrote: > Hi guys, > > Is libsemanage (and libsepol) still supported on policies without MLS/MCS? > For some reason, I get segfaults when using libsemanage-2.1.6 on a "strict" > policy (one without levels). > > The backtrace is as follows: > > (gdb) run -B > Starting program: /usr/sbin/semodule -B > > Program received signal SIGSEGV, Segmentation fault. > __strlen_sse2 () at ../sysdeps/x86_64/multiarch/../strlen.S:32 > 32 ../sysdeps/x86_64/multiarch/../strlen.S: No such file or directory. > in ../sysdeps/x86_64/multiarch/../strlen.S > (gdb) bt > #0 __strlen_sse2 () at ../sysdeps/x86_64/multiarch/../strlen.S:32 > #1 0x000003a1d08ddce1 in ustr_replace_cstr () from /usr/lib64/libustr-1.0.so.1 > #2 0x000003a1d1524835 in replace_all (str=0x3a1d88e93c0 "HOME_DIR/.+\tsystem_u:object_r:user_home_t", repl=0x3ffffffde00) > at genhomedircon.c:499 > #3 0x000003a1d1524b58 in write_home_dir_context (s=0x3ffffffdf20, out=0x3a1d7444510, tpl=0x3a1d6e1f1b0, > user=0x3a1d71b2680 "user_u", seuser=0x3a1d71b2680 "user_u", home=0x3a1d71e08a3 "/home/[^/]*", > role_prefix=0x3a1d71bafc0 "user", level=0x0) at genhomedircon.c:566 > #4 0x000003a1d1525d68 in write_context_file (s=0x3ffffffdf20, out=0x3a1d7444510) at genhomedircon.c:998 > #5 0x000003a1d1526054 in semanage_genhomedircon (sh=0x3a1d1b6b280, policydb=0x3a1d6e01dd0, usepasswd=1, ignoredirs=0x0) > at genhomedircon.c:1076 > #6 0x000003a1d151e30c in semanage_direct_commit (sh=0x3a1d1b6b280) at direct_api.c:994 > #7 0x000003a1d15234fe in semanage_commit (sh=0x3a1d1b6b280) at handle.c:435 > #8 0x000003a1d1969318 in main (argc=<optimized out>, argv=0x3ffffffe278) at semodule.c:466 > > As you can see in frame #3, level is 0x0, which is confirmed when > traversing the &s variable in the write_context_file function: > > (gdb) frame 4 > #4 0x000003a1d1525d68 in write_context_file (s=0x3ffffffdf20, out=0x3a1d7444510) at genhomedircon.c:998 > 998 genhomedircon.c: No such file or directory. > in genhomedircon.c > (gdb) print s.fallback_user_level > $1 = 0x0 > (gdb) print s.fallback_user > $2 = 0x3a1d71b2680 "user_u" > (gdb) print s.fallback_user_prefix > $3 = 0x3a1d71bafc0 "user" > > Looking at how this can become 0x0, I think that > > 1. write_context_file calls setup_fallback_user > 2. setup_fallback_user calls semanage_user_query (for a default account?) > this returns >= 0 > 3. setup_fallback_user calls semanage_user_get_mlslevel > 4. semanage_user_get_mlslevel eventually calls sepol_user_get_mlslevel > 5. sepol_user_get_mlslevel returns 0x0 > > Should sepol_user_get_mlslevel return some default (like "s0") if the > system doesn't use MLS/MCS? Or shouldn't it be called if one doesn't have > MCS/MLS? Looks the same to me as: http://marc.info/?t=131443240600002&r=1&w=2 http://marc.info/?t=132433045500005&r=1&w=2 It seems that last patch never got applied. The non-MCS/MLS case doesn't get much testing since most of the distributions seem to enable MCS in their default policies. -- Stephen Smalley National Security Agency -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@xxxxxxxxxxxxx with the words "unsubscribe selinux" without quotes as the message.
