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* elf: Add glibc-hwcaps support for LD_LIBRARY_PATHFlorian Weimer2020-12-041-5/+15
| | | | | | | | | | | | | | | | | | | | This hacks non-power-set processing into _dl_important_hwcaps. Once the legacy hwcaps handling goes away, the subdirectory handling needs to be reworked, but it is premature to do this while both approaches are still supported. ld.so supports two new arguments, --glibc-hwcaps-prepend and --glibc-hwcaps-mask. Each accepts a colon-separated list of glibc-hwcaps subdirectory names. The prepend option adds additional subdirectories that are searched first, in the specified order. The mask option restricts the automatically selected subdirectories to those listed in the option argument. For example, on systems where /usr/lib64 is on the library search path, --glibc-hwcaps-prepend=valgrind:debug causes the dynamic loader to search the directories /usr/lib64/glibc-hwcaps/valgrind and /usr/lib64/glibc-hwcaps/debug just before /usr/lib64 is searched. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl: Move stack list variables into _rtld_globalFlorian Weimer2020-11-161-3/+16
| | | | | | | | | Now __thread_gscope_wait (the function behind THREAD_GSCOPE_WAIT, formerly __wait_lookup_done) can be implemented directly in ld.so, eliminating the unprotected GL (dl_wait_lookup_done) function pointer. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Do not pass GLRO(dl_platform), GLRO(dl_platformlen) to _dl_important_hwcapsFlorian Weimer2020-10-091-6/+6
| | | | | | | In the current code, the function can easily obtain the information on its own. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Record whether paths come from LD_LIBRARY_PATH or --library-pathFlorian Weimer2020-10-081-2/+4
| | | | | | This allows more precise LD_DEBUG diagnostics. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Implement _dl_writeFlorian Weimer2020-10-071-0/+6
| | | | | | | | The generic version is parallel to _dl_writev. It cannot use _dl_writev directly because the errno value needs to be obtained under a lock. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* rtld: Avoid using up static TLS surplus for optimizations [BZ #25051]Szabolcs Nagy2020-07-081-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | On some targets static TLS surplus area can be used opportunistically for dynamically loaded modules such that the TLS access then becomes faster (TLSDESC and powerpc TLS optimization). However we don't want all surplus TLS to be used for this optimization because dynamically loaded modules with initial-exec model TLS can only use surplus TLS. The new contract for surplus static TLS use is: - libc.so can have up to 192 bytes of IE TLS, - other system libraries together can have up to 144 bytes of IE TLS. - Some "optional" static TLS is available for opportunistic use. The optional TLS is now tunable: rtld.optional_static_tls, so users can directly affect the allocated static TLS size. (Note that module unloading with dlclose does not reclaim static TLS. After the optional TLS runs out, TLS access is no longer optimized to use static TLS.) The default setting of rtld.optional_static_tls is 512 so the surplus TLS is 3*192 + 4*144 + 512 = 1664 by default, the same as before. Fixes BZ #25051. Tested on aarch64-linux-gnu and x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* rtld: Account static TLS surplus for audit modulesSzabolcs Nagy2020-07-081-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | The new static TLS surplus size computation is surplus_tls = 192 * (nns-1) + 144 * nns + 512 where nns is controlled via the rtld.nns tunable. This commit accounts audit modules too so nns = rtld.nns + audit modules. rtld.nns should only include the namespaces required by the application, namespaces for audit modules are accounted on top of that so audit modules don't use up the static TLS that is reserved for the application. This allows loading many audit modules without tuning rtld.nns or using up static TLS, and it fixes FAIL: elf/tst-auditmany Note that DL_NNS is currently a hard upper limit for nns, and if rtld.nns + audit modules go over the limit that's a fatal error. By default rtld.nns is 4 which allows 12 audit modules. Counting the audit modules is based on existing audit string parsing code, we cannot use GLRO(dl_naudit) before the modules are actually loaded.
* rtld: Add rtld.nns tunable for the number of supported namespacesSzabolcs Nagy2020-07-081-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | TLS_STATIC_SURPLUS is 1664 bytes currently which is not enough to support DL_NNS (== 16) number of dynamic link namespaces, if we assume 192 bytes of TLS are reserved for libc use and 144 bytes are reserved for other system libraries that use IE TLS. A new tunable is introduced to control the number of supported namespaces and to adjust the surplus static TLS size as follows: surplus_tls = 192 * (rtld.nns-1) + 144 * rtld.nns + 512 The default is rtld.nns == 4 and then the surplus TLS size is the same as before, so the behaviour is unchanged by default. If an application creates more namespaces than the rtld.nns setting allows, then it is not guaranteed to work, but the limit is not checked. So existing usage will continue to work, but in the future if an application creates more than 4 dynamic link namespaces then the tunable will need to be set. In this patch DL_NNS is a fixed value and provides a maximum to the rtld.nns setting. Static linking used fixed 2048 bytes surplus TLS, this is changed so the same contract is used as for dynamic linking. With static linking DL_NNS == 1 so rtld.nns tunable is forced to 1, so by default the surplus TLS is reduced to 144 + 512 = 656 bytes. This change is not expected to cause problems. Tested on aarch64-linux-gnu and x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* rtld: Clean up PT_NOTE and add PT_GNU_PROPERTY handlingSzabolcs Nagy2020-07-081-0/+4
| | | | | | | | | | | | | | | | | | | | | | Add generic code to handle PT_GNU_PROPERTY notes. Invalid content is ignored, _dl_process_pt_gnu_property is always called after PT_LOAD segments are mapped and it has no failure modes. Currently only one NT_GNU_PROPERTY_TYPE_0 note is handled, which contains target specific properties: the _dl_process_gnu_property hook is called for each property. The old _dl_process_pt_note and _rtld_process_pt_note differ in how the program header is read. The old _dl_process_pt_note is called before PT_LOAD segments are mapped and _rtld_process_pt_note is called after PT_LOAD segments are mapped. The old _rtld_process_pt_note is removed and _dl_process_pt_note is always called after PT_LOAD segments are mapped and now it has no failure modes. The program headers are scanned backwards so that PT_NOTE can be skipped if PT_GNU_PROPERTY exists. Co-Authored-By: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Turn _dl_printf, _dl_error_printf, _dl_fatal_printf into functionsFlorian Weimer2020-05-251-12/+7
| | | | | | | | | | | | | | This change makes it easier to set a breakpoint on these calls. This also addresses the issue that including <ldsodefs.h> without <unistd.h> does not result usable _dl_*printf macros because of the use of the STD*_FILENO macros there. (The private symbol for _dl_fatal_printf will go away again once the exception handling implementation is unified between libc and ld.so.) Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Implement __libc_early_initFlorian Weimer2020-04-241-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function is defined in libc.so, and the dynamic loader calls right after relocation has been finished, before any ELF constructors or the preinit function is invoked. It is also used in the static build for initializing parts of the static libc. To locate __libc_early_init, a direct symbol lookup function is used, _dl_lookup_direct. It does not search the entire symbol scope and consults merely a single link map. This function could also be used to implement lookups in the vDSO (as an optimization). A per-namespace variable (libc_map) is added for locating libc.so, to avoid repeated traversals of the search scope. It is similar to GL(dl_initfirst). An alternative would have been to thread a context argument from _dl_open down to _dl_map_object_from_fd (where libc.so is identified). This could have avoided the global variable, but the change would be larger as a result. It would not have been possible to use this to replace GL(dl_initfirst) because that global variable is used to pass the function pointer past the stack switch from dl_main to the main program. Replacing that requires adding a new argument to _dl_init, which in turn needs changes to the architecture-specific libc.so startup code written in assembler. __libc_early_init should not be used to replace _dl_var_init (as it exists today on some architectures). Instead, _dl_lookup_direct should be used to look up a new variable symbol in libc.so, and that should then be initialized from the dynamic loader, immediately after the object has been loaded in _dl_map_object_from_fd (before relocation is run). This way, more IFUNC resolvers which depend on these variables will work. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* elf: Move vDSO setup to rtld (BZ#24967)Adhemerval Zanella2020-01-031-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | This patch moves the vDSO setup from libc to loader code, just after the vDSO link_map setup. For static case the initialization is moved to _dl_non_dynamic_init instead. Instead of using the mangled pointer, the vDSO data is set as attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for static). It is read-only even with partial relro. It fixes BZ#24967 now that the vDSO pointer is setup earlier than malloc interposition is called. Also, vDSO calls should not be a problem for static dlopen as indicated by BZ#20802. The vDSO pointer would be zero-initialized and the syscall will be issued instead. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and sparcv9-linux-gnu. I also run some tests on mips. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* Update copyright dates with scripts/update-copyrights.Joseph Myers2020-01-011-1/+1
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* Avoid late dlopen failure due to scope, TLS slotinfo updates [BZ #25112]Florian Weimer2019-11-271-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | This change splits the scope and TLS slotinfo updates in dlopen into two parts: one to resize the data structures, and one to actually apply the update. The call to add_to_global_resize in dl_open_worker is moved before the demarcation point at which no further memory allocations are allowed. _dl_add_to_slotinfo is adjusted to make the list update optional. There is some optimization possibility here because we could grow the slotinfo list of arrays in a single call, one the largest TLS modid is known. This commit does not fix the fatal meory allocation failure in _dl_update_slotinfo. Ideally, this error during dlopen should be recoverable. The update order of scopes and TLS data structures is retained, although it appears to be more correct to fully initialize TLS first, and then expose symbols in the newly loaded objects via the scope update. Tested on x86_64-linux-gnu. Change-Id: I240c58387dabda3ca1bcab48b02115175fa83d6c
* Avoid late failure in dlopen in global scope update [BZ #25112]Florian Weimer2019-11-271-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | The call to add_to_global in dl_open_worker happens after running ELF constructors for new objects. At this point, proper recovery from malloc failure would be quite complicated: We would have to run the ELF destructors and close all opened objects, something that we currently do not do. Instead, this change splits add_to_global into two phases, add_to_global_resize (which can raise an exception, called before ELF constructors run), and add_to_global_update (which cannot, called after ELF constructors). A complication arises due to recursive dlopen: After the inner dlopen consumes some space, the pre-allocation in the outer dlopen may no longer be sufficient. A new member in the namespace structure, _ns_global_scope_pending_adds keeps track of the maximum number of objects that need to be added to the global scope. This enables the inner add_to_global_resize call to take into account the needs of an outer dlopen. Most code in the dynamic linker assumes that the number of global scope entries fits into an unsigned int (matching the r_nlist member of struct r_scop_elem). Therefore, change the type of _ns_global_scope_alloc to unsigned int (from size_t), and add overflow checks. Change-Id: Ie08e2f318510d5a6a4bcb1c315f46791b5b77524
* Introduce DL_LOOKUP_FOR_RELOCATE flag for _dl_lookup_symbol_xFlorian Weimer2019-11-211-0/+3
| | | | | | | | | | This will allow changes in dependency processing during non-lazy binding, for more precise processing of NODELETE objects: During initial relocation in dlopen, the fate of NODELETE objects is still unclear, so objects which are depended upon by NODELETE objects cannot immediately be marked as NODELETE. Change-Id: Ic7b94a3f7c4719a00ca8e6018088567824da0658
* Enhance _dl_catch_exception to allow disabling exception handlingFlorian Weimer2019-11-161-1/+3
| | | | | | | | | | | | In some cases, it is necessary to introduce noexcept regions where raised dynamic loader exceptions (e.g., from lazy binding) are fatal, despite being nested in a code region with an active exception handler. This change enhances _dl_catch_exception with to provide such a capability. The existing function is reused, so that it is not necessary to introduce yet another function with a similar purpose. Change-Id: Iec1bf642ff95a349fdde8040e9baf851ac7b8904
* Avoid zero-length array at the end of struct link_map [BZ #25097]Florian Weimer2019-11-151-4/+13
| | | | | | | | | | | | l_audit ends up as an internal array with _rtld_global, and GCC 10 warns about this. This commit does not change the layout of _rtld_global, so it is suitable for backporting. Future changes could allocate more of the audit state dynamically and remove it from always-allocated data structures, to optimize the common case of inactive auditing. Change-Id: Ic911100730f9124d4ea977ead8e13cee64b84d45
* Introduce link_map_audit_state accessor functionFlorian Weimer2019-11-151-1/+7
| | | | | | | | | | | | To improve GCC 10 compatibility, it is necessary to remove the l_audit zero-length array from the end of struct link_map. In preparation of that, this commit introduces an accessor function for the audit state, so that it is possible to change the representation of the audit state without adjusting the code that accesses it. Tested on x86_64-linux-gnu. Built on i686-gnu. Change-Id: Id815673c29950fc011ae5301d7cde12624f658df
* slotinfo in struct dtv_slotinfo_list should be flexible array [BZ #25097]Florian Weimer2019-11-121-1/+1
| | | | | | | | | GCC 10 will warn about subscribing inner length zero arrays. Use a GCC extension in csu/libc-tls.c to allocate space for the static_slotinfo variable. Adjust nptl_db so that the type description machinery does not attempt to determine the size of the flexible array member slotinfo. Change-Id: I51be146a7857186a4ede0bb40b332509487bdde8
* Prefer https to http for gnu.org and fsf.org URLsPaul Eggert2019-09-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
* MIPS support for GNU hashMihailo Stojanovic2019-08-291-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a reimplementation of [1], which was submitted back in 2015. Copyright issue has been sorted [2] last year. It proposed a new section (.gnu.xhash) and related dynamic tag (GT_GNU_XHASH). The new section would be virtually identical to the existing .gnu.hash except for the translation table (xlat) which would contain correct MIPS .dynsym indexes corresponding to the hashvals in chains. This is because MIPS ABI imposes a different ordering of the dynsyms than the one expected by the .gnu.hash section. Another addition would be a leading word at the beggining of the section, which would contain the number of entries in the translation table. In this patch, the new section name and dynamic tag are changed to reflect the fact that the section should be treated as MIPS specific (.MIPS.xhash and DT_MIPS_XHASH). This patch addresses the alignment issue reported in [3] which is caused by the leading word of the .MIPS.xhash section. Leading word is now removed in the corresponding binutils patch, and the number of entries in the translation table is computed using DT_MIPS_SYMTABNO dynamic tag. Since the MIPS specific dl-lookup.c file was removed following the initial patch submission, I opted for the definition of three new macros in the generic ldsodefs.h. ELF_MACHINE_GNU_HASH_ADDRIDX defines the index of the dynamic tag in the l_info array. ELF_MACHINE_HASH_SYMIDX is used to calculate the index of a symbol in GNU hash. On MIPS, it is defined to look up the symbol index in the translation table. ELF_MACHINE_XHASH_SETUP is defined for MIPS only. It initializes the .MIPS.xhash pointer in the link_map_machine struct. The other major change is bumping the highest EI_ABIVERSION value for MIPS to suggest that the dynamic linker now supports GNU hash. The patch was tested by running the glibc testsuite for the three MIPS ABIs (o32, n32 and n64) and for x86_64-linux-gnu. [1] https://sourceware.org/ml/binutils/2015-10/msg00057.html [2] https://sourceware.org/ml/binutils/2018-03/msg00025.html [3] https://sourceware.org/ml/binutils/2016-01/msg00006.html * elf/dl-addr.c (determine_info): Calculate the symbol index using the newly defined ELF_MACHINE_HASH_SYMIDX macro. * elf/dl-lookup.c (do_lookup_x): Ditto. (_dl_setup_hash): Initialize MIPS xhash translation table. * elf/elf.h (SHT_MIPS_XHASH): New define. (DT_MIPS_XHASH): New define. * sysdeps/generic/ldsodefs.h (ELF_MACHINE_GNU_HASH_ADDRIDX): New define. (ELF_MACHINE_HASH_SYMIDX): Ditto. (ELF_MACHINE_XHASH_SETUP): Ditto. * sysdeps/mips/ldsodefs.h (ELF_MACHINE_GNU_HASH_ADDRIDX): New define. (ELF_MACHINE_HASH_SYMIDX): Ditto. (ELF_MACHINE_XHASH_SETUP): Ditto. * sysdeps/mips/linkmap.h (struct link_map_machine): New member. * sysdeps/unix/sysv/linux/mips/ldsodefs.h: Increment valid ABI version. * sysdeps/unix/sysv/linux/mips/libc-abis: New ABI version.
* nptl: Remove pthread_clock_gettime pthread_clock_settimeAdhemerval Zanella2019-03-221-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes CLOCK_THREAD_CPUTIME_ID and CLOCK_PROCESS_CPUTIME_ID support from clock_gettime and clock_settime generic implementation. For Linux, kernel already provides supports through the syscall and Hurd HTL lacks __pthread_clock_gettime and __pthread_clock_settime internal implementation. As described in clock_gettime man-page [1] on 'Historical note for SMP system', implementing CLOCK_{THREAD,PROCESS}_CPUTIME_ID with timer registers is error-prone and susceptible to timing and accurary issues that the libc can not deal without kernel support. This allows removes unused code which, however, still incur in some runtime overhead in thread creation (the struct pthread cpuclock_offset initialization). If hurd eventually wants to support them it should either either implement as a kernel facility (or something related due its architecture) or in system specific implementation. Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. I also checked on a i686-gnu build. * nptl/Makefile (libpthread-routines): Remove pthread_clock_gettime and pthread_clock_settime. * nptl/pthreadP.h (__find_thread_by_id): Remove prototype. * elf/dl-support.c [!HP_TIMING_NOAVAIL] (_dl_cpuclock_offset): Remove. (_dl_non_dynamic_init): Remove _dl_cpuclock_offset setting. * elf/rtld.c (_dl_start_final): Likewise. * nptl/allocatestack.c (__find_thread_by_id): Remove function. * sysdeps/generic/ldsodefs.h [!HP_TIMING_NOAVAIL] (_dl_cpuclock_offset): Remove. * sysdeps/mach/hurd/dl-sysdep.c [!HP_TIMING_NOAVAIL] (_dl_cpuclock_offset): Remove. * nptl/descr.h (struct pthread): Rename cpuclock_offset to cpuclock_offset_ununsed. * nptl/nptl-init.c (__pthread_initialize_minimal_internal): Remove cpuclock_offset set. * nptl/pthread_create.c (START_THREAD_DEFN): Likewise. * sysdeps/nptl/fork.c (__libc_fork): Likewise. * nptl/pthread_clock_gettime.c: Remove file. * nptl/pthread_clock_settime.c: Likewise. * sysdeps/unix/clock_gettime.c (hp_timing_gettime): Remove function. [HP_TIMING_AVAIL] (realtime_gettime): Remove CLOCK_THREAD_CPUTIME_ID and CLOCK_PROCESS_CPUTIME_ID support. * sysdeps/unix/clock_settime.c (hp_timing_gettime): Likewise. [HP_TIMING_AVAIL] (realtime_gettime): Likewise. * sysdeps/posix/clock_getres.c (hp_timing_getres): Likewise. [HP_TIMING_AVAIL] (__clock_getres): Likewise. * sysdeps/unix/clock_nanosleep.c (CPUCLOCK_P, INVALID_CLOCK_P): Likewise. (__clock_nanosleep): Remove CPUCLOCK_P and INVALID_CLOCK_P usage. [1] http://man7.org/linux/man-pages/man2/clock_gettime.2.html
* elf: Remove remnants of MAP_ANON emulationFlorian Weimer2019-03-041-4/+0
| | | | | | Most of the code was removed in commit 20739e5454c12acbc0479387fe795c5b19a4166f ("* elf/dl-load.c: Remove support for systems without MAP_ANON.").
* Update copyright dates with scripts/update-copyrights.Joseph Myers2019-01-011-1/+1
| | | | | | | * All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
* elf: Correct absolute (SHN_ABS) symbol run-time calculation [BZ #19818]Maciej W. Rozycki2018-04-041-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Do not relocate absolute symbols by the base address. Such symbols have SHN_ABS as the section index and their value is not supposed to be affected by relocation as per the ELF gABI[1]: "SHN_ABS The symbol has an absolute value that will not change because of relocation." The reason for our non-conformance here seems to be an old SysV linker bug causing symbols like _DYNAMIC to be incorrectly emitted as absolute symbols[2]. However in a previous discussion it was pointed that this is seriously flawed by preventing the lone purpose of the existence of absolute symbols from being used[3]: "On the contrary, the only interpretation that makes sense to me is that it will not change because of relocation at link time or at load time. Absolute symbols, from the days of the earliest linking loaders, have been used to represent addresses that are outside the address space of the module (e.g., memory-mapped addresses or kernel gateway pages). They've even been used to represent true symbolic constants (e.g., system entry point numbers, sizes, version numbers). There's no other way to represent a true absolute symbol, while the meaning you seek is easily represented by giving the symbol a non-negative st_shndx value." and we ought to stop supporting our current broken interpretation. Update processing for dladdr(3) and dladdr1(3) so that SHN_ABS symbols are ignored, because under the corrected interpretation they do not represent addresses within a mapped file and therefore are not supposed to be considered. References: [1] "System V Application Binary Interface - DRAFT - 19 October 2010", The SCO Group, Section "Symbol Table", <http://www.sco.com/developers/gabi/2012-12-31/ch4.symtab.html> [2] Alan Modra, "Absolute symbols" <https://sourceware.org/ml/binutils/2012-05/msg00019.html> [3] Cary Coutant, "Re: Absolute symbols" <https://sourceware.org/ml/binutils/2012-05/msg00020.html> [BZ #19818] * sysdeps/generic/ldsodefs.h (SYMBOL_ADDRESS): Handle SHN_ABS symbols. * elf/dl-addr.c (determine_info): Ignore SHN_ABS symbols. * elf/tst-absolute-sym.c: New file. * elf/tst-absolute-sym-lib.c: New file. * elf/tst-absolute-sym-lib.lds: New file. * elf/Makefile (tests): Add `tst-absolute-sym'. (modules-names): Add `tst-absolute-sym-lib'. (LDLIBS-tst-absolute-sym-lib.so): New variable. ($(objpfx)tst-absolute-sym-lib.so): New dependency. ($(objpfx)tst-absolute-sym): New dependency.
* elf: Unify symbol address run-time calculation [BZ #19818]Maciej W. Rozycki2018-04-041-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wrap symbol address run-time calculation into a macro and use it throughout, replacing inline calculations. There are a couple of variants, most of them different in a functionally insignificant way. Most calculations are right following RESOLVE_MAP, at which point either the map or the symbol returned can be checked for validity as the macro sets either both or neither. In some places both the symbol and the map has to be checked however. My initial implementation therefore always checked both, however that resulted in code larger by as much as 0.3%, as many places know from elsewhere that no check is needed. I have decided the size growth was unacceptable. Having looked closer I realized that it's the map that is the culprit. Therefore I have modified LOOKUP_VALUE_ADDRESS to accept an additional boolean argument telling it to access the map without checking it for validity. This in turn has brought quite nice results, with new code actually being smaller for i686, and MIPS o32, n32 and little-endian n64 targets, unchanged in size for x86-64 and, unusually, marginally larger for big-endian MIPS n64, as follows: i686: text data bss dec hex filename 152255 4052 192 156499 26353 ld-2.27.9000-base.so 152159 4052 192 156403 262f3 ld-2.27.9000-elf-symbol-value.so MIPS/o32/el: text data bss dec hex filename 142906 4396 260 147562 2406a ld-2.27.9000-base.so 142890 4396 260 147546 2405a ld-2.27.9000-elf-symbol-value.so MIPS/n32/el: text data bss dec hex filename 142267 4404 260 146931 23df3 ld-2.27.9000-base.so 142171 4404 260 146835 23d93 ld-2.27.9000-elf-symbol-value.so MIPS/n64/el: text data bss dec hex filename 149835 7376 408 157619 267b3 ld-2.27.9000-base.so 149787 7376 408 157571 26783 ld-2.27.9000-elf-symbol-value.so MIPS/o32/eb: text data bss dec hex filename 142870 4396 260 147526 24046 ld-2.27.9000-base.so 142854 4396 260 147510 24036 ld-2.27.9000-elf-symbol-value.so MIPS/n32/eb: text data bss dec hex filename 142019 4404 260 146683 23cfb ld-2.27.9000-base.so 141923 4404 260 146587 23c9b ld-2.27.9000-elf-symbol-value.so MIPS/n64/eb: text data bss dec hex filename 149763 7376 408 157547 2676b ld-2.27.9000-base.so 149779 7376 408 157563 2677b ld-2.27.9000-elf-symbol-value.so x86-64: text data bss dec hex filename 148462 6452 400 155314 25eb2 ld-2.27.9000-base.so 148462 6452 400 155314 25eb2 ld-2.27.9000-elf-symbol-value.so [BZ #19818] * sysdeps/generic/ldsodefs.h (LOOKUP_VALUE_ADDRESS): Add `set' parameter. (SYMBOL_ADDRESS): New macro. [!ELF_FUNCTION_PTR_IS_SPECIAL] (DL_SYMBOL_ADDRESS): Use SYMBOL_ADDRESS for symbol address calculation. * elf/dl-runtime.c (_dl_fixup): Likewise. (_dl_profile_fixup): Likewise. * elf/dl-symaddr.c (_dl_symbol_address): Likewise. * elf/rtld.c (dl_main): Likewise. * sysdeps/aarch64/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/alpha/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/arm/dl-machine.h (elf_machine_rel): Likewise. (elf_machine_rela): Likewise. * sysdeps/hppa/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/hppa/dl-symaddr.c (_dl_symbol_address): Likewise. * sysdeps/i386/dl-machine.h (elf_machine_rel): Likewise. (elf_machine_rela): Likewise. * sysdeps/ia64/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/m68k/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/microblaze/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/mips/dl-machine.h (ELF_MACHINE_BEFORE_RTLD_RELOC): Likewise. (elf_machine_reloc): Likewise. (elf_machine_got_rel): Likewise. * sysdeps/mips/dl-trampoline.c (__dl_runtime_resolve): Likewise. * sysdeps/nios2/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/powerpc/powerpc32/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/powerpc/powerpc64/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/riscv/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/s390/s390-32/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/s390/s390-64/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/sh/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/sparc/sparc32/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/sparc/sparc64/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/tile/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* hurd: Fix calling __pthread_initialize_minimal in shared caseSamuel Thibault2018-03-251-1/+1
| | | | | * sysdeps/generic/ldsodefs.h [SHARED] (__pthread_initialize_minimal): Declare function.
* hurd: add gscope supportSamuel Thibault2018-03-111-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | * elf/dl-support.c [!THREAD_GSCOPE_IN_TCB] (_dl_thread_gscope_count): Define variable. * sysdeps/generic/ldsodefs.h [!THREAD_GSCOPE_IN_TCB] (struct rtld_global): Add _dl_thread_gscope_count member. * sysdeps/mach/hurd/tls.h: Include <atomic.h>. [!defined __ASSEMBLER__] (THREAD_GSCOPE_GLOBAL, THREAD_GSCOPE_SET_FLAG, THREAD_GSCOPE_RESET_FLAG, THREAD_GSCOPE_WAIT): Define macros. * sysdeps/generic/tls.h: Document THREAD_GSCOPE_IN_TCB. * sysdeps/aarch64/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/alpha/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/arm/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/hppa/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/i386/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/ia64/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/m68k/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/microblaze/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/mips/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/nios2/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/powerpc/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/riscv/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/s390/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/sh/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/sparc/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/tile/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1. * sysdeps/x86_64/nptl/tls.h: Define THREAD_GSCOPE_IN_TCB to 1.
* elf: Remove ad-hoc restrictions on dlopen callers [BZ #22787]Florian Weimer2018-02-211-5/+0
| | | | | | | | | | | | | | | | | | | | | | This looks like a post-exploitation hardening measure: If an attacker is able to redirect execution flow, they could use that to load a DSO which contains additional code (or perhaps make the stack executable). However, the checks are not in the correct place to be effective: If they are performed before the critical operation, an attacker with sufficient control over execution flow could simply jump directly to the code which performs the operation, bypassing the check. The check would have to be executed unconditionally after the operation and terminate the process in case a caller violation was detected. Furthermore, in _dl_check_caller, there was a fallback reading global writable data (GL(dl_rtld_map).l_map_start and GL(dl_rtld_map).l_text_end), which could conceivably be targeted by an attacker to disable the check, too. Other critical functions (such as system) remain completely unprotected, so the value of these additional checks does not appear that large. Therefore this commit removes this functionality.
* Update copyright dates with scripts/update-copyrights.Joseph Myers2018-01-011-1/+1
| | | | | | | * All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
* elf: remove redundant is_path argumentDmitry V. Levin2017-12-271-2/+2
| | | | | | | | | | | is_path argument is no longer used and could be safely removed. * elf/dl-dst.h (DL_DST_COUNT): Remove is_path argument, all callers updated. * elf/dl-load.c (is_dst, _dl_dst_count, _dl_dst_substitute, expand_dynamic_string_token): Likewise. * sysdeps/generic/ldsodefs.h (_dl_dst_count, _dl_dst_substitute): Remove is_path argument.
* ld.so: Examine GLRO to detect inactive loader [BZ #20204]Florian Weimer2017-12-181-1/+19
| | | | | | | | | | | | GLRO (_rtld_global_ro) is read-only after initialization and can therefore not be patched at run time, unlike the hook table addresses and their contents, so this is a desirable hardening feature. The hooks are only needed if ld.so has not been initialized, and this happens only after static dlopen (dlmopen uses a single ld.so object across all namespaces). Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Add --enable-static-pie configure option to build static PIE [BZ #19574]H.J. Lu2017-12-151-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Static PIE extends address space layout randomization to static executables. It provides additional security hardening benefits at the cost of some memory and performance. Dynamic linker, ld.so, is a standalone program which can be loaded at any address. This patch adds a configure option, --enable-static-pie, to embed the part of ld.so in static executable to create static position independent executable (static PIE). A static PIE is similar to static executable, but can be loaded at any address without help from a dynamic linker. When --enable-static-pie is used to configure glibc, libc.a is built as PIE and all static executables, including tests, are built as static PIE. The resulting libc.a can be used together with GCC 8 or above to build static PIE with the compiler option, -static-pie. But GCC 8 isn't required to build glibc with --enable-static-pie. Only GCC with PIE support is needed. When an older GCC is used to build glibc with --enable-static-pie, proper input files are passed to linker to create static executables as static PIE, together with "-z text" to prevent dynamic relocations in read-only segments, which are not allowed in static PIE. The following changes are made for static PIE: 1. Add a new function, _dl_relocate_static_pie, to: a. Get the run-time load address. b. Read the dynamic section. c. Perform dynamic relocations. Dynamic linker also performs these steps. But static PIE doesn't load any shared objects. 2. Call _dl_relocate_static_pie at entrance of LIBC_START_MAIN in libc.a. crt1.o, which is used to create dynamic and non-PIE static executables, is updated to include a dummy _dl_relocate_static_pie. rcrt1.o is added to create static PIE, which will link in the real _dl_relocate_static_pie. grcrt1.o is also added to create static PIE with -pg. GCC 8 has been updated to support rcrt1.o and grcrt1.o for static PIE. Static PIE can work on all architectures which support PIE, provided: 1. Target must support accessing of local functions without dynamic relocations, which is needed in start.S to call __libc_start_main with function addresses of __libc_csu_init, __libc_csu_fini and main. All functions in static PIE are local functions. If PIE start.S can't reach main () defined in a shared object, the code sequence: pass address of local_main to __libc_start_main ... local_main: tail call to main via PLT can be used. 2. start.S is updated to check PIC instead SHARED for PIC code path and avoid dynamic relocation, when PIC is defined and SHARED isn't defined, to support static PIE. 3. All assembly codes are updated check PIC instead SHARED for PIC code path to avoid dynamic relocations in read-only sections. 4. All assembly codes are updated check SHARED instead PIC for static symbol name. 5. elf_machine_load_address in dl-machine.h are updated to support static PIE. 6. __brk works without TLS nor dynamic relocations in read-only section so that it can be used by __libc_setup_tls to initializes TLS in static PIE. NB: When glibc is built with GCC defaulted to PIE, libc.a is compiled with -fPIE, regardless if --enable-static-pie is used to configure glibc. When glibc is configured with --enable-static-pie, libc.a is compiled with -fPIE, regardless whether GCC defaults to PIE or not. The same libc.a can be used to build both static executable and static PIE. There is no need for separate PIE copy of libc.a. On x86-64, the normal static sln: text data bss dec hex filename 625425 8284 5456 639165 9c0bd elf/sln the static PIE sln: text data bss dec hex filename 657626 20636 5392 683654 a6e86 elf/sln The code size is increased by 5% and the binary size is increased by 7%. Linker requirements to build glibc with --enable-static-pie: 1. Linker supports --no-dynamic-linker to remove PT_INTERP segment from static PIE. 2. Linker can create working static PIE. The x86-64 linker needs the fix for https://sourceware.org/bugzilla/show_bug.cgi?id=21782 The i386 linker needs to be able to convert "movl main@GOT(%ebx), %eax" to "leal main@GOTOFF(%ebx), %eax" if main is defined locally. Binutils 2.29 or above are OK for i686 and x86-64. But linker status for other targets need to be verified. 3. Linker should resolve undefined weak symbols to 0 in static PIE: https://sourceware.org/bugzilla/show_bug.cgi?id=22269 4. Many ELF backend linkers incorrectly check bfd_link_pic for TLS relocations, which should check bfd_link_executable instead: https://sourceware.org/bugzilla/show_bug.cgi?id=22263 Tested on aarch64, i686 and x86-64. Using GCC 7 and binutils master branch, build-many-glibcs.py with --enable-static-pie with all patches for static PIE applied have the following build successes: PASS: glibcs-aarch64_be-linux-gnu build PASS: glibcs-aarch64-linux-gnu build PASS: glibcs-armeb-linux-gnueabi-be8 build PASS: glibcs-armeb-linux-gnueabi build PASS: glibcs-armeb-linux-gnueabihf-be8 build PASS: glibcs-armeb-linux-gnueabihf build PASS: glibcs-arm-linux-gnueabi build PASS: glibcs-arm-linux-gnueabihf build PASS: glibcs-arm-linux-gnueabihf-v7a build PASS: glibcs-arm-linux-gnueabihf-v7a-disable-multi-arch build PASS: glibcs-m68k-linux-gnu build PASS: glibcs-microblazeel-linux-gnu build PASS: glibcs-microblaze-linux-gnu build PASS: glibcs-mips64el-linux-gnu-n32 build PASS: glibcs-mips64el-linux-gnu-n32-nan2008 build PASS: glibcs-mips64el-linux-gnu-n32-nan2008-soft build PASS: glibcs-mips64el-linux-gnu-n32-soft build PASS: glibcs-mips64el-linux-gnu-n64 build PASS: glibcs-mips64el-linux-gnu-n64-nan2008 build PASS: glibcs-mips64el-linux-gnu-n64-nan2008-soft build PASS: glibcs-mips64el-linux-gnu-n64-soft build PASS: glibcs-mips64-linux-gnu-n32 build PASS: glibcs-mips64-linux-gnu-n32-nan2008 build PASS: glibcs-mips64-linux-gnu-n32-nan2008-soft build PASS: glibcs-mips64-linux-gnu-n32-soft build PASS: glibcs-mips64-linux-gnu-n64 build PASS: glibcs-mips64-linux-gnu-n64-nan2008 build PASS: glibcs-mips64-linux-gnu-n64-nan2008-soft build PASS: glibcs-mips64-linux-gnu-n64-soft build PASS: glibcs-mipsel-linux-gnu build PASS: glibcs-mipsel-linux-gnu-nan2008 build PASS: glibcs-mipsel-linux-gnu-nan2008-soft build PASS: glibcs-mipsel-linux-gnu-soft build PASS: glibcs-mips-linux-gnu build PASS: glibcs-mips-linux-gnu-nan2008 build PASS: glibcs-mips-linux-gnu-nan2008-soft build PASS: glibcs-mips-linux-gnu-soft build PASS: glibcs-nios2-linux-gnu build PASS: glibcs-powerpc64le-linux-gnu build PASS: glibcs-powerpc64-linux-gnu build PASS: glibcs-tilegxbe-linux-gnu-32 build PASS: glibcs-tilegxbe-linux-gnu build PASS: glibcs-tilegx-linux-gnu-32 build PASS: glibcs-tilegx-linux-gnu build PASS: glibcs-tilepro-linux-gnu build and the following build failures: FAIL: glibcs-alpha-linux-gnu build elf/sln is failed to link due to: assertion fail bfd/elf64-alpha.c:4125 This is caused by linker bug and/or non-PIC code in PIE libc.a. FAIL: glibcs-hppa-linux-gnu build elf/sln is failed to link due to: collect2: fatal error: ld terminated with signal 11 [Segmentation fault] https://sourceware.org/bugzilla/show_bug.cgi?id=22537 FAIL: glibcs-ia64-linux-gnu build elf/sln is failed to link due to: collect2: fatal error: ld terminated with signal 11 [Segmentation fault] FAIL: glibcs-powerpc-linux-gnu build FAIL: glibcs-powerpc-linux-gnu-soft build FAIL: glibcs-powerpc-linux-gnuspe build FAIL: glibcs-powerpc-linux-gnuspe-e500v1 build elf/sln is failed to link due to: ld: read-only segment has dynamic relocations. This is caused by linker bug and/or non-PIC code in PIE libc.a. See: https://sourceware.org/bugzilla/show_bug.cgi?id=22264 FAIL: glibcs-powerpc-linux-gnu-power4 build elf/sln is failed to link due to: findlocale.c:96:(.text+0x22c): @local call to ifunc memchr This is caused by linker bug and/or non-PIC code in PIE libc.a. FAIL: glibcs-s390-linux-gnu build elf/sln is failed to link due to: collect2: fatal error: ld terminated with signal 11 [Segmentation fault], core dumped assertion fail bfd/elflink.c:14299 This is caused by linker bug and/or non-PIC code in PIE libc.a. FAIL: glibcs-sh3eb-linux-gnu build FAIL: glibcs-sh3-linux-gnu build FAIL: glibcs-sh4eb-linux-gnu build FAIL: glibcs-sh4eb-linux-gnu-soft build FAIL: glibcs-sh4-linux-gnu build FAIL: glibcs-sh4-linux-gnu-soft build elf/sln is failed to link due to: ld: read-only segment has dynamic relocations. This is caused by linker bug and/or non-PIC code in PIE libc.a. See: https://sourceware.org/bugzilla/show_bug.cgi?id=22263 Also TLS code sequence in SH assembly syscalls in glibc doesn't match TLS code sequence expected by ld: https://sourceware.org/bugzilla/show_bug.cgi?id=22270 FAIL: glibcs-sparc64-linux-gnu build FAIL: glibcs-sparcv9-linux-gnu build FAIL: glibcs-tilegxbe-linux-gnu build FAIL: glibcs-tilegxbe-linux-gnu-32 build FAIL: glibcs-tilegx-linux-gnu build FAIL: glibcs-tilegx-linux-gnu-32 build FAIL: glibcs-tilepro-linux-gnu build elf/sln is failed to link due to: ld: read-only segment has dynamic relocations. This is caused by linker bug and/or non-PIC code in PIE libc.a. See: https://sourceware.org/bugzilla/show_bug.cgi?id=22263 [BZ #19574] * INSTALL: Regenerated. * Makeconfig (real-static-start-installed-name): New. (pic-default): Updated for --enable-static-pie. (pie-default): New for --enable-static-pie. (default-pie-ldflag): Likewise. (+link-static-before-libc): Replace $(DEFAULT-LDFLAGS-$(@F)) with $(if $($(@F)-no-pie),$(no-pie-ldflag),$(default-pie-ldflag)). Replace $(static-start-installed-name) with $(real-static-start-installed-name). (+prectorT): Updated for --enable-static-pie. (+postctorT): Likewise. (CFLAGS-.o): Add $(pie-default). (CFLAGS-.op): Likewise. * NEWS: Mention --enable-static-pie. * config.h.in (ENABLE_STATIC_PIE): New. * configure.ac (--enable-static-pie): New configure option. (have-no-dynamic-linker): New LIBC_CONFIG_VAR. (have-static-pie): Likewise. Enable static PIE if linker supports --no-dynamic-linker. (ENABLE_STATIC_PIE): New AC_DEFINE. (enable-static-pie): New LIBC_CONFIG_VAR. * configure: Regenerated. * csu/Makefile (omit-deps): Add r$(start-installed-name) and gr$(start-installed-name) for --enable-static-pie. (extra-objs): Likewise. (install-lib): Likewise. (extra-objs): Add static-reloc.o and static-reloc.os ($(objpfx)$(start-installed-name)): Also depend on $(objpfx)static-reloc.o. ($(objpfx)r$(start-installed-name)): New. ($(objpfx)g$(start-installed-name)): Also depend on $(objpfx)static-reloc.os. ($(objpfx)gr$(start-installed-name)): New. * csu/libc-start.c (LIBC_START_MAIN): Call _dl_relocate_static_pie in libc.a. * csu/libc-tls.c (__libc_setup_tls): Add main_map->l_addr to initimage. * csu/static-reloc.c: New file. * elf/Makefile (routines): Add dl-reloc-static-pie. (elide-routines.os): Likewise. (DEFAULT-LDFLAGS-tst-tls1-static-non-pie): Removed. (tst-tls1-static-non-pie-no-pie): New. * elf/dl-reloc-static-pie.c: New file. * elf/dl-support.c (_dl_get_dl_main_map): New function. * elf/dynamic-link.h (ELF_DURING_STARTUP): Also check STATIC_PIE_BOOTSTRAP. * elf/get-dynamic-info.h (elf_get_dynamic_info): Likewise. * gmon/Makefile (tests): Add tst-gmon-static-pie. (tests-static): Likewise. (DEFAULT-LDFLAGS-tst-gmon-static): Removed. (tst-gmon-static-no-pie): New. (CFLAGS-tst-gmon-static-pie.c): Likewise. (CRT-tst-gmon-static-pie): Likewise. (tst-gmon-static-pie-ENV): Likewise. (tests-special): Likewise. ($(objpfx)tst-gmon-static-pie.out): Likewise. (clean-tst-gmon-static-pie-data): Likewise. ($(objpfx)tst-gmon-static-pie-gprof.out): Likewise. * gmon/tst-gmon-static-pie.c: New file. * manual/install.texi: Document --enable-static-pie. * sysdeps/generic/ldsodefs.h (_dl_relocate_static_pie): New. (_dl_get_dl_main_map): Likewise. * sysdeps/i386/configure.ac: Check if linker supports static PIE. * sysdeps/x86_64/configure.ac: Likewise. * sysdeps/i386/configure: Regenerated. * sysdeps/x86_64/configure: Likewise. * sysdeps/mips/Makefile (ASFLAGS-.o): Add $(pie-default). (ASFLAGS-.op): Likewise.
* Consolidate link map sortingAndreas Schwab2017-11-271-2/+2
| | | | | | Combine the four places where link maps are sorted into a single function. This also moves the logic to skip the first map (representing the main binary) to the callers.
* ld.so: Add architecture specific fieldsH.J. Lu2017-11-131-4/+7
| | | | | | | | | | | | | | | | | | | | | | To support Intel Control-flow Enforcement Technology (CET) run-time control: 1. An architecture specific field in the writable ld.so namespace is needed to indicate if CET features are enabled at run-time. 2. An architecture specific field in struct link_map is needed if CET features are enabled in an ELF module. This patch adds dl-procruntime.c to the writable ld.so namespace and link_map.h to struct link_map. Tested with build-many-glibcs.py. * elf/dl-support.c: Include <dl-procruntime.c>. * include/link.h: Include <link_map.h>. * sysdeps/generic/dl-procruntime.c: New file. * sysdeps/generic/link_map.h: Likewise. * sysdeps/generic/ldsodefs.h: Include <dl-procruntime.c> in the writable ld.so namespace.
* Mark internal functions with attribute_hidden [BZ #18822]H.J. Lu2017-10-011-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mark internal functions with attribute_hidden to allow direct access to internal functions within libc.so and libc.a without using GOT nor PLT. Size comparison of libc.so: On x86-64: text data bss dec hex Before: 1728577 20584 17088 1766249 1af369 After : 1728593 20584 17088 1766265 1af379 The only change is __gconv_release_shlib in iconv/gconv_dl.c is inlined since it is hidden, which increases the code size of gconv_dl.os by 18 bytes. On i686: text data bss dec hex Before: 1869039 11444 11112 1891595 1cdd0b After : 1868635 11444 11112 1891191 1cdb77 The code size is decreased by avoiding GOT/PLT for hidden functions. [BZ #18822] * iconv/gconv_int.h (__gconv_open): Add attribute_hidden. (__gconv_close): Likewise. (__gconv): Likewise. (__gconv_find_transform): Likewise. (__gconv_lookup_cache): Likewise. (__gconv_compare_alias_cache): Likewise. (__gconv_load_cache): Likewise. (__gconv_get_path): Likewise. (__gconv_close_transform): Likewise. (__gconv_release_cache): Likewise. (__gconv_find_shlib): Likewise. (__gconv_release_shlib): Likewise. (__gconv_get_builtin_trans): Likewise. (__gconv_compare_alias): Likewise. * include/dlfcn.h (_dlerror_run): Likewise. * include/stdio.h (__fortify_fail_abort): Likewise. * include/time.h (__tz_compute): Likewise. (__strptime_internal): Likewise. * intl/gettextP.h (_nl_find_domain): Likewise. (_nl_load_domain): Likewise. (_nl_find_msg): Likewise. * intl/plural-exp.h (FREE_EXPRESSION): Likewise. (EXTRACT_PLURAL_EXPRESSION): Likewise. * locale/coll-lookup.h (__collidx_table_lookup): Likewise. * resolv/gai_misc.h (__gai_enqueue_request): Likewise. (__gai_find_request): Likewise. (__gai_remove_request): Likewise. (__gai_notify): Likewise. (__gai_notify_only): Likewise. * sysdeps/generic/aio_misc.h (__aio_sigqueue): Likewise. * sysdeps/generic/ldsodefs.h (_dl_fini): Likewise. (_dl_non_dynamic_init): Likewise. (_dl_aux_init): Likewise. * sysdeps/i386/machine-gmon.h (mcount_internal): Likewise. * sysdeps/unix/sysv/linux/i386/olddirent.h (__old_getdents64): Likewise. * wcsmbs/wcsmbsload.h (__wcsmbs_load_conv): Likewise. (__wcsmbs_clone_conv): Likewise. (__wcsmbs_named_conv): Likewise.
* elf: Remove internal_function attributeFlorian Weimer2017-08-311-61/+37
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* _dl_init: Remove internal_function attributeFlorian Weimer2017-08-141-1/+1
| | | | | The function is called from the i386 startup code, which needs minor adjustments due to the changed ABI.
* _dl_fini: Remove internal_function attributeFlorian Weimer2017-08-141-1/+1
| | | | | | | | | | Assembler code passes the address of _dl_fini to __libc_start_main, whose function pointer argument lacks the attribute. This means that calls could use the wrong ABI. Fortunately, for zero-parameter void-returning functions, internal_function does not change ABI on i386 (the only architecture which uses internal_function), so this inconsistency was harmless (which is why it had not been noticed so far).
* ld.so: Remove internal_function attribute from various functionsFlorian Weimer2017-08-131-11/+8
| | | | | These functions are invoked from other DSOs and should therefore use the standard calling convention.
* NPTL: Remove internal_function from stack marking functionsFlorian Weimer2017-08-131-2/+2
| | | | | These are called across DSO boundaries and therefore should use the ABI calling convention.
* ld.so: Introduce struct dl_exceptionFlorian Weimer2017-08-101-21/+86
| | | | | | This commit separates allocating and raising exceptions. This simplifies catching and re-raising them because it is no longer necessary to make a temporary, on-stack copy of the exception message.
* ld.so: Consolidate 2 strtouls into _dl_strtoul [BZ #21528]H.J. Lu2017-06-081-0/+4
| | | | | | | | | | | | | | | | | | | | | There are 2 minimal strtoul implementations in ld.so: 1. __strtoul_internal in elf/dl-minimal.c. 2. tunables_strtoul in elf/dl-tunables.c. This patch adds _dl_strtoul to replace them. Tested builds with and without --enable-tunables. [BZ #21528] * elf/dl-minimal.c (__strtoul_internal): Removed. (strtoul): Likewise. * elf/dl-misc.c (_dl_strtoul): New function. * elf/dl-tunables.c (tunables_strtoul): Removed. (tunable_initialize): Replace tunables_strtoul with _dl_strtoul. * elf/rtld.c (process_envvars): Likewise. * sysdeps/unix/sysv/linux/dl-librecon.h (_dl_osversion_init): Likewise. * sysdeps/generic/ldsodefs.h (_dl_strtoul): New prototype.
* tunables: Use glibc.tune.hwcap_mask tunable instead of _dl_hwcap_maskSiddhesh Poyarekar2017-06-071-0/+2
| | | | | | | | | | | | | | | | | | | | | | | Drop _dl_hwcap_mask when building with tunables. This completes the transition of hwcap_mask reading from _dl_hwcap_mask to tunables. * elf/dl-hwcaps.h: New file. * elf/dl-hwcaps.c: Include it. (_dl_important_hwcaps)[HAVE_TUNABLES]: Read and update glibc.tune.hwcap_mask. * elf/dl-cache.c: Include dl-hwcaps.h. (_dl_load_cache_lookup)[HAVE_TUNABLES]: Read glibc.tune.hwcap_mask. * sysdeps/sparc/sparc32/dl-machine.h: Likewise. * elf/dl-support.c (_dl_hwcap2)[HAVE_TUNABLES]: Drop _dl_hwcap_mask. * elf/rtld.c (rtld_global_ro)[HAVE_TUNABLES]: Drop _dl_hwcap_mask. (process_envvars)[HAVE_TUNABLES]: Likewise. * sysdeps/generic/ldsodefs.h (rtld_global_ro)[HAVE_TUNABLES]: Likewise. * sysdeps/x86/cpu-features.c (init_cpu_features): Don't initialize dl_hwcap_mask when tunables are enabled.
* Update copyright dates with scripts/update-copyrights.Joseph Myers2017-01-011-1/+1
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* Initialize the stack guard earlier when linking statically [BZ #7065]Nick Alcock2016-12-261-0/+11
| | | | | | | | | | | | | | | | | | | | The address of the stack canary is stored in a per-thread variable, which means that we must ensure that the TLS area is intialized before calling any -fstack-protector'ed functions. For dynamically linked applications, we ensure this (in a later patch) by disabling -fstack-protector for the whole dynamic linker, but for static applications, the AT_ENTRY address is called directly by the kernel, so we must deal with the problem differently. In static appliations, __libc_setup_tls performs the TCB setup and TLS initialization, so this commit arranges for it to be called early and unconditionally. The call (and the stack guard initialization) is before the DL_SYSDEP_OSCHECK hook, which if set will probably call functions which are stack-protected (it does on Linux and NaCL too). We also move apply_irel up, so that we can still safely call functions that require ifuncs while in __libc_setup_tls (though if stack-protection is enabled we still have to avoid calling functions that are not stack-protected at this stage).
* Remove unused function _dl_tls_setupFlorian Weimer2016-12-211-6/+0
| | | | | | Commit 7a5e3d9d633c828d84a9535f26b202a6179978e7 (elf: Assume TLS is initialized in _dl_map_object_from_fd) removed the last call of _dl_tls_setup, but did not remove the function itself.
* Implement _dl_catch_error, _dl_signal_error in libc.so [BZ #16628]Florian Weimer2016-11-301-18/+28
| | | | | | | | | | | | | | | | | | This change moves the main implementation of _dl_catch_error, _dl_signal_error to libc.so, where TLS variables can be used directly. This removes a writable function pointer from the rtld_global variable. For use during initial relocation, minimal implementations of these functions are provided in ld.so. These are eventually interposed by the libc.so implementations. This is implemented by compiling elf/dl-error-skeleton.c twice, via elf/dl-error.c and elf/dl-error-minimal.c. As a side effect of this change, the static version of dl-error.c no longer includes support for the _dl_signal_cerror/_dl_receive_error mechanism because it is only used in ld.so.
* Treat STV_HIDDEN and STV_INTERNAL symbols as STB_LOCALMaciej W. Rozycki2016-07-011-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a reference to PR ld/19908 make ld.so respect symbol export classes aka visibility and treat STV_HIDDEN and STV_INTERNAL symbols as local, preventing such symbols from preempting exported symbols. According to the ELF gABI[1] neither STV_HIDDEN nor STV_INTERNAL symbols are supposed to be present in linked binaries: "A hidden symbol contained in a relocatable object must be either removed or converted to STB_LOCAL binding by the link-editor when the relocatable object is included in an executable file or shared object." "An internal symbol contained in a relocatable object must be either removed or converted to STB_LOCAL binding by the link-editor when the relocatable object is included in an executable file or shared object." however some GNU binutils versions produce such symbols in some cases. PR ld/19908 is one and we also have this note in scripts/abilist.awk: so clearly there is linked code out there which contains such symbols which is prone to symbol table misinterpretation, and it'll be more productive if we handle this gracefully, under the Robustness Principle: "be liberal in what you accept, and conservative in what you produce", especially as this is a simple (STV_HIDDEN|STV_INTERNAL) => STB_LOCAL mapping. References: [1] "System V Application Binary Interface - DRAFT - 24 April 2001", The Santa Cruz Operation, Inc., "Symbol Table", <http://www.sco.com/developers/gabi/2001-04-24/ch4.symtab.html> * sysdeps/generic/ldsodefs.h (dl_symbol_visibility_binds_local_p): New inline function. * elf/dl-addr.c (determine_info): Treat hidden and internal symbols as local. * elf/dl-lookup.c (do_lookup_x): Likewise. * elf/dl-reloc.c (RESOLVE_MAP): Likewise.
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