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* Fix range check in do_tunable_update_valAlexey Makhalov2017-09-271-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current implementation of tunables does not set arena_max and arena_test values. Any value provided by glibc.malloc.arena_max and glibc.malloc.arena_test parameters is ignored. These tunables have minval value set to 1 (see elf/dl-tunables.list file) and undefined maxval value. In that case default value (which is 0. see scripts/gen-tunables.awk) is being used to set maxval. For instance, generated tunable_list[] entry for arena_max is: (gdb) p *cur $1 = {name = 0x7ffff7df6217 "glibc.malloc.arena_max", type = {type_code = TUNABLE_TYPE_SIZE_T, min = 1, max = 0}, val = {numval = 0, strval = 0x0}, initialized = false, security_level = TUNABLE_SECLEVEL_SXID_IGNORE, env_alias = 0x7ffff7df622e "MALLOC_ARENA_MAX"} As a result, any value of glibc.malloc.arena_max is ignored by TUNABLE_SET_VAL_IF_VALID_RANGE macro __type min = (__cur)->type.min; <- initialized to 1 __type max = (__cur)->type.max; <- initialized to 0! if (min == max) <- false { min = __default_min; max = __default_max; } if ((__type) (__val) >= min && (__type) (val) <= max) <- false { (__cur)->val.numval = val; (__cur)->initialized = true; } Assigning correct min/max values at a build time fixes a problem. Plus, a bit of optimization: Setting of default min/max values for the given type at a run time might be eliminated. * elf/dl-tunables.c (do_tunable_update_val): Range checking fix. * scripts/gen-tunables.awk: Set unspecified minval and/or maxval values to correct default value for given type.
* Fix gen-tunables.awk to work with older awkAdhemerval Zanella2017-06-191-34/+34
| | | | | | | Awk 3.1.x does not support multi-dimensional arrays, so fix up to make sure that gen-tunables.awk works on it. * scripts/gen-tunables.awk: Avoid multi-dimensional arrays.
* tunables: Add LD_HWCAP_MASK to tunablesSiddhesh Poyarekar2017-06-071-0/+1
| | | | | | | | | | | | | | | | Add LD_HWCAP_MASK to tunables in preparation of it being removed from rtld.c. This allows us to read LD_HWCAP_MASK much earlier so that it can influence IFUNC resolution in aarch64. This patch does not actually do anything other than read the LD_HWCAP_MASK variable and add the tunables way to set the LD_HWCAP_MASK, i.e. via the glibc.tune.hwcap_mask tunable. In a follow-up patch, the _dl_hwcap_mask will be replaced with glibc.tune.hwcap_mask to complete the transition. * elf/dl-tunables.list: Add glibc.tune.hwcap_mask. * scripts/gen-tunables.awk: Include dl-procinfo.h. * manual/tunables.texi: Document glibc.tune.hwcap_mask.
* tunables: Specify a default value for tunablesSiddhesh Poyarekar2017-05-171-2/+10
| | | | | | | | | Enhance dl-tunables.list to allow specifying a default value for a tunable that it would be initialized to. * scripts/gen-tunables.awk: Recognize 'default' keyword in dl-tunables.list. * README.tunables: Document it.
* tunables: Make tunable_list relroSiddhesh Poyarekar2017-05-111-1/+1
| | | | | | | | | | | | | | | | | As of now we don't need tunables to be writable after they have been set initially, so there is no point in having them writable. Put tunable_list in .data.rel.ro so that it is set as read-only after relocation. This also allows us to move some of the dl_* variables that are tunables controlled into the tunables infrastructure instead of having two copies. In future if we ever need specific tunables to be writable at runtime, we can split the tunable_list into two. Regression tested on x86_64 to verify that tests continue to pass. * scripts/gen-tunables.awk: Add attribute_relro to tunable_list.
* Update old tunables framework document/script.Sunyeop Lee2017-03-241-6/+6
| | | | | | | | | | | Since commit 8b9e9c3c0bae497ad5e2d0ae2f333f62feddcc12, security_level replaces is_secure. There were some old files need to be updated. 2017-03-23 Sunyeop Lee <sunyeop97@gmail.com> * README.tunables: Updated descriptions. * elf/dl-tunables.list: Fixed typo: SXID_NONE -> NONE. * scripts/gen-tunables.awk: Updated the code related to the commit.
* tunables: Fix environment variable processing for setuid binaries (bz #21073)Siddhesh Poyarekar2017-02-021-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Florian Weimer pointed out that we have three different kinds of environment variables (and hence tunables): 1. Variables that are removed for setxid processes 2. Variables that are ignored in setxid processes but is passed on to child processes 3. Variables that are passed on to child processes all the time Tunables currently only does (2) and (3) when it should be doing (1) for MALLOC_CHECK_. This patch enhances the is_secure flag in tunables to an enum value that can specify which of the above three categories the tunable (and its envvar alias) belongs to. The default is for tunables to be in (1). Hence, all of the malloc tunables barring MALLOC_CHECK_ are explicitly specified to belong to category (2). There were discussions around abolishing category (2) completely but we can do that as a separate exercise in 2.26. Tested on x86_64 to verify that there are no regressions. [BZ #21073] * elf/dl-tunable-types.h (tunable_seclevel_t): New enum. * elf/dl-tunables.c (tunables_strdup): Remove. (get_next_env): Also return the previous envp. (parse_tunables): Erase tunables of category TUNABLES_SECLEVEL_SXID_ERASE. (maybe_enable_malloc_check): Make MALLOC_CHECK_ TUNABLE_SECLEVEL_NONE if /etc/setuid-debug is accessible. (__tunables_init)[TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring]: Update GLIBC_TUNABLES envvar after parsing. [TUNABLES_FRONTEND != TUNABLES_FRONTEND_valstring]: Erase tunable envvars of category TUNABLES_SECLEVEL_SXID_ERASE. * elf/dl-tunables.h (struct _tunable): Change member is_secure to security_level. * elf/dl-tunables.list: Add security_level annotations for all tunables. * scripts/gen-tunables.awk: Recognize and generate enum values for security_level. * elf/tst-env-setuid.c: New test case. * elf/tst-env-setuid-tunables: new test case. * elf/Makefile (tests-static): Add them.
* Add framework for tunablesSiddhesh Poyarekar2016-12-311-0/+157
The tunables framework allows us to uniformly manage and expose global variables inside glibc as switches to users. tunables/README has instructions for glibc developers to add new tunables. Tunables support can be enabled by passing the --enable-tunables configure flag to the configure script. This patch only adds a framework and does not pose any limitations on how tunable values are read from the user. It also adds environment variables used in malloc behaviour tweaking to the tunables framework as a PoC of the compatibility interface. * manual/install.texi: Add --enable-tunables option. * INSTALL: Regenerate. * README.tunables: New file. * Makeconfig (CPPFLAGS): Define TOP_NAMESPACE. (before-compile): Generate dl-tunable-list.h early. * config.h.in: Add HAVE_TUNABLES. * config.make.in: Add have-tunables. * configure.ac: Add --enable-tunables option. * configure: Regenerate. * csu/init-first.c (__libc_init_first): Move __libc_init_secure earlier... * csu/init-first.c (LIBC_START_MAIN):... to here. Include dl-tunables.h, libc-internal.h. (LIBC_START_MAIN) [!SHARED]: Initialize tunables for static binaries. * elf/Makefile (dl-routines): Add dl-tunables. * elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE namespace. * elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_ only when !HAVE_TUNABLES. * elf/rtld.c (process_envvars): Likewise. * elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h (_dl_sysdep_start): Call __tunables_init. * elf/dl-tunable-types.h: New file. * elf/dl-tunables.c: New file. * elf/dl-tunables.h: New file. * elf/dl-tunables.list: New file. * malloc/tst-malloc-usable-static.c: New test case. * malloc/Makefile (tests-static): Add it. * malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h. Define TUNABLE_NAMESPACE. (DL_TUNABLE_CALLBACK (set_mallopt_check)): New function. (DL_TUNABLE_CALLBACK_FNDECL): New macro. Use it to define callback functions. (ptmalloc_init): Set tunable values. * scripts/gen-tunables.awk: New file. * sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h. (_dl_sysdep_start): Call __tunables_init.