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2021-07-26Exclude static tests for mcheck and malloc-checkSiddhesh Poyarekar1-10/+3
mcheck and malloc-check no longer work with static binaries, so drop those tests. Reported-by: Samuel Thibault <samuel.thibault@gnu.org> Tested-by: Samuel Thibault <samuel.thibault@gnu.org> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
2021-07-23Fix build and tests with --disable-tunablesSiddhesh Poyarekar3-30/+28
Remove unused code and declare __libc_mallopt when !IS_IN (libc) to allow the debug hook to build with --disable-tunables. Also, run tst-ifunc-isa-2* tests only when tunables are enabled since the result depends on it. Tested on x86_64. Reported-by: Matheus Castanho <msc@linux.ibm.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22mcheck Fix malloc_usable_size [BZ #22057]Siddhesh Poyarekar3-3/+9
Interpose malloc_usable_size to return the correct mcheck value for malloc_usable_size. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22Remove malloc hooks [BZ #23328]Siddhesh Poyarekar4-41/+41
Make malloc hooks symbols compat-only so that new applications cannot link against them and remove the declarations from the API. Also remove the unused malloc-hooks.h. Finally, mark all symbols in libc_malloc_debug.so as compat so that the library cannot be linked against. Add a note about the deprecation in NEWS. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22Move malloc_{g,s}et_state to libc_malloc_debugSiddhesh Poyarekar5-167/+193
These deprecated functions are only safe to call from __malloc_initialize_hook and as a result, are not useful in the general case. Move the implementations to libc_malloc_debug so that existing binaries that need it will now have to preload the debug DSO to work correctly. This also allows simplification of the core malloc implementation by dropping all the undumping support code that was added to make malloc_set_state work. One known breakage is that of ancient emacs binaries that depend on this. They will now crash when running with this libc. With LD_BIND_NOW=1, it will terminate immediately because of not being able to find malloc_set_state but with lazy binding it will crash in unpredictable ways. It will need a preloaded libc_malloc_debug.so so that its initialization hook is executed to allow its malloc implementation to work properly. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22glibc.malloc.check: Wean away from malloc hooksSiddhesh Poyarekar7-80/+213
The malloc-check debugging feature is tightly integrated into glibc malloc, so thanks to an idea from Florian Weimer, much of the malloc implementation has been moved into libc_malloc_debug.so to support malloc-check. Due to this, glibc malloc and malloc-check can no longer work together; they use altogether different (but identical) structures for heap management. This should not make a difference though since the malloc check hook is not disabled anywhere. malloc_set_state does, but it does so early enough that it shouldn't cause any problems. The malloc check tunable is now in the debug DSO and has no effect when the DSO is not preloaded. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22mtrace: Wean away from malloc hooksSiddhesh Poyarekar4-302/+253
Wean mtrace away from the malloc hooks and move them into the debug DSO. Split the API away from the implementation so that we can add the API to libc.so as well as libc_malloc_debug.so, with the libc implementations being empty. Update localplt data since memalign no longer has any callers after this change. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22Simplify __malloc_initializedSiddhesh Poyarekar2-18/+18
Now that mcheck no longer needs to check __malloc_initialized (and no other third party hook can since the symbol is not exported), make the variable boolean and static so that it is used strictly within malloc. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22mcheck: Wean away from malloc hooks [BZ #23489]Siddhesh Poyarekar6-458/+592
Split the mcheck implementation into the debugging hooks and API so that the API can be replicated in libc and libc_malloc_debug.so. The libc APIs always result in failure. The mcheck implementation has also been moved entirely into libc_malloc_debug.so and with it, all of the hook initialization code can now be moved into the debug library. Now the initialization can be done independently of libc internals. With this patch, libc_malloc_debug.so can no longer be used with older libcs, which is not its goal anyway. tst-vfork3 breaks due to this since it spawns shell scripts, which in turn execute using the system glibc. Move the test to tests-container so that only the built glibc is used. This move also fixes bugs in the mcheck version of memalign and realloc, thus allowing removal of the tests from tests-mcheck exclusion list. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22Move malloc hooks into a compat DSOSiddhesh Poyarekar13-111/+453
Remove all malloc hook uses from core malloc functions and move it into a new library libc_malloc_debug.so. With this, the hooks now no longer have any effect on the core library. libc_malloc_debug.so is a malloc interposer that needs to be preloaded to get hooks functionality back so that the debugging features that depend on the hooks, i.e. malloc-check, mcheck and mtrace work again. Without the preloaded DSO these debugging features will be nops. These features will be ported away from hooks in subsequent patches. Similarly, legacy applications that need hooks functionality need to preload libc_malloc_debug.so. The symbols exported by libc_malloc_debug.so are maintained at exactly the same version as libc.so. Finally, static binaries will no longer be able to use malloc debugging features since they cannot preload the debugging DSO. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22Remove __morecore and __default_morecoreSiddhesh Poyarekar6-46/+19
Make the __morecore and __default_morecore symbols compat-only and remove their declarations from the API. Also, include morecore.c directly into malloc.c; this should ideally get merged into malloc in a future cleanup. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22Remove __after_morecore_hookSiddhesh Poyarekar3-24/+6
Remove __after_morecore_hook from the API and finalize the symbol so that it can no longer be used in new applications. Old applications using __after_morecore_hook will find that their hook is no longer called. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22Make mcheck tests conditional on GLIBC_2.23 or earlierSiddhesh Poyarekar1-0/+3
Targets with base versions of 2.24 or later won't have __malloc_initialize_hook because of which the tests will essentially be the same as the regular malloc tests. Avoid running them instead and save time. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22malloc: Fix tst-mallocfork3-malloc-check linkSamuel Thibault1-0/+1
It uses pthread.
2021-07-19tst-safe-linking: make false positives even more improbableSiddhesh Poyarekar1-6/+25
There is a 1 in 16 chance of a corruption escaping safe-linking and to guard against spurious failures, tst-safe-linking runs each subtest 10 times to ensure that the chance is reduced to 1 in 2^40. However, in the 1 in 16 chance that a corruption does escape safe linking, it could well be caught by other sanity checks we do in malloc, which then results in spurious test failures like below: test test_fastbin_consolidate failed with a different error expected: malloc_consolidate(): unaligned fastbin chunk detected actual: malloc_consolidate(): invalid chunk size This failure is seen more frequently on i686; I was able to reproduce it in about 5 min of running it in a loop. Guard against such failures by recording them and retrying the test. Also, do not fail the test if we happened to get defeated by the 1 in 2^40 odds if in at least one of the instances it was detected by other checks. Finally, bolster the odds to 2^64 by running 16 times instead of 10. The test still has a chance of failure so it is still flaky in theory. However in practice if we see a failure here then it's more likely that there's a bug than it being an issue with the test. Add more printfs and also dump them to stdout so that in the event the test actually fails, we will have some data to try and understand why it may have failed. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-12mcheck: Align struct hdr to MALLOC_ALIGNMENT bytes [BZ #28068]H.J. Lu2-2/+5
1. Align struct hdr to MALLOC_ALIGNMENT bytes so that malloc hooks in libmcheck align memory to MALLOC_ALIGNMENT bytes. 2. Remove tst-mallocalign1 from tests-exclude-mcheck for i386 and x32. 3. Add tst-pvalloc-fortify and tst-reallocarray to tests-exclude-mcheck since they use malloc_usable_size (see BZ #22057). This fixed BZ #28068. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-07-09Force building with -fno-commonFlorian Weimer2-2/+2
As a result, is not necessary to specify __attribute__ ((nocommon)) on individual definitions. GCC 10 defaults to -fno-common on all architectures except ARC, but this change is compatible with older GCC versions and ARC, too. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-09Add a generic malloc test for MALLOC_ALIGNMENTH.J. Lu3-40/+73
1. Add sysdeps/generic/malloc-size.h to define size related macros for malloc. 2. Move x86_64/tst-mallocalign1.c to malloc and replace ALIGN_MASK with MALLOC_ALIGN_MASK. 3. Add tst-mallocalign1 to tests-exclude-mcheck for i386 and x32 since mcheck doesn't honor MALLOC_ALIGNMENT.
2021-07-08_int_realloc is staticSiddhesh Poyarekar1-2/+2
_int_realloc is correctly declared at the top to be static, but incorrectly defined without the static keyword. Fix that. The generated binaries have identical code.
2021-07-08Move mcheck symbol from stdlib to mallocSiddhesh Poyarekar1-1/+1
It is defined in malloc, so it belongs there. Verified on x86_64 that the built libraries are identical despite this change.
2021-07-08Harden tcache double-free checkSiddhesh Poyarekar2-4/+41
The tcache allocator layer uses the tcache pointer as a key to identify a block that may be freed twice. Since this is in the application data area, an attacker exploiting a use-after-free could potentially get access to the entire tcache structure through this key. A detailed write-up was provided by Awarau here: https://awaraucom.wordpress.com/2020/07/19/house-of-io-remastered/ Replace this static pointer use for key checking with one that is generated at malloc initialization. The first attempt is through getrandom with a fallback to random_bits(), which is a simple pseudo-random number generator based on the clock. The fallback ought to be sufficient since the goal of the randomness is only to make the key arbitrary enough that it is very unlikely to collide with user data. Co-authored-by: Eyal Itkin <eyalit@checkpoint.com>
2021-07-07tests-exclude-mcheck: Fix typoSiddhesh Poyarekar1-1/+1
It's tst-realloc, not tst-posix-realloc. Verified this time to ensure that the total number of tests reduced by 1. Reported-by: Stefan Liebler <stli@linux.ibm.com>
2021-07-06Exclude tst-realloc from tests-mcheckSiddhesh Poyarekar1-1/+2
The realloc (NULL, 0) test in tst-realloc fails with gcc 7.x but passes with newer gcc. This is because a newer gcc transforms the realloc call to malloc (0), thus masking the bug in mcheck. Disable the test with mcheck for now. The malloc removal patchset will fix this and then remove this test from the exclusion list. Reported-by: Stefan Liebler <stli@linux.ibm.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-04hooks.c: Remove incorrect commentSiddhesh Poyarekar1-4/+0
The comment about different values of glibc.malloc.check is no longer valid.
2021-07-02mtrace: Add attribute nocommon to mallwatchTulio Magno Quites Machado Filho1-1/+1
Avoid compilation errors GCC versions that do not default to -fno-common, e.g. GCC <= 9. Fixes commit 00d28960c5388a582a0485e07629b553c32dde49 ("mtrace: Deprecate mallwatch and tr_break"). Suggested-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Suggested-by: Florian Weimer <fweimer@redhat.com>
2021-07-03Move glibc.malloc.check implementation into its own fileSiddhesh Poyarekar2-370/+391
Separate the malloc check implementation from the malloc hooks. They still use the hooks but are now maintained in a separate file. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-03mtrace: Deprecate mallwatch and tr_breakSiddhesh Poyarekar1-37/+20
The variable and function pair appear to provide a way for users to set conditional breakpoints in mtrace when a specific address is returned by the allocator. This can be achieved by using conditional breakpoints in gdb so it is redundant. There is no documentation of this interface in the manual either, so it appears to have been a hack that got added to debug malloc. Deprecate these symbols and do not call tr_break anymore. Reviewed-by: DJ Delorie <dj@redhat.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-03Drop source dependencies on hooks.c and arena.cSiddhesh Poyarekar1-4/+0
Dependencies on hooks.c and arena.c get auto-computed when generating malloc.o{,s}.d so there is no need to add them manually. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Andreas Schwab <schwab@linux-m68k.org>
2021-07-02malloc: Initiate tcache shutdown even without allocations [BZ #28028]JeffyChen1-1/+2
After commit 1e26d35193efbb29239c710a4c46a64708643320 ("malloc: Fix tcache leak after thread destruction [BZ #22111]"), tcache_shutting_down is still not early enough. When we detach a thread with no tcache allocated, tcache_shutting_down would still be false. Reviewed-by: DJ Delorie <dj@redhat.com>
2021-07-02Add mcheck tests to mallocSiddhesh Poyarekar1-0/+35
Like malloc-check, add generic rules to run all tests in malloc by linking with libmcheck.a so as to provide coverage for mcheck(). Currently the following 12 tests fail: FAIL: malloc/tst-malloc-backtrace-mcheck FAIL: malloc/tst-malloc-fork-deadlock-mcheck FAIL: malloc/tst-malloc-stats-cancellation-mcheck FAIL: malloc/tst-malloc-tcache-leak-mcheck FAIL: malloc/tst-malloc-thread-exit-mcheck FAIL: malloc/tst-malloc-thread-fail-mcheck FAIL: malloc/tst-malloc-usable-static-mcheck FAIL: malloc/tst-malloc-usable-static-tunables-mcheck FAIL: malloc/tst-malloc-usable-tunables-mcheck FAIL: malloc/tst-malloc_info-mcheck FAIL: malloc/tst-memalign-mcheck FAIL: malloc/tst-posix_memalign-mcheck and they have been added to tests-exclude-mcheck for now to keep status quo. At least the last two can be attributed to bugs in mcheck() but I haven't fixed them here since they should be fixed by removing malloc hooks. Others need to be triaged to check if they're due to mcheck bugs or due to actual bugs. Reviewed-by: DJ Delorie <dj@redhat.com>
2021-06-28posix: Add _Fork [BZ #4737]Adhemerval Zanella2-0/+216
Austin Group issue 62 [1] dropped the async-signal-safe requirement for fork and provided a async-signal-safe _Fork replacement that does not run the atfork handlers. It will be included in the next POSIX standard. It allow to close a long standing issue to make fork AS-safe (BZ#4737). As indicated on the bug, besides the internal lock for the atfork handlers itself; there is no guarantee that the handlers itself will not introduce more AS-safe issues. The idea is synchronize fork with the required internal locks to allow children in multithread processes to use mostly of standard function (even though POSIX states only AS-safe function should be used). On signal handles, _Fork should be used intead and only AS-safe functions should be used. For testing, the new tst-_Fork only check basic usage. I also added a new tst-mallocfork3 which uses the same strategy to check for deadlock of tst-mallocfork2 but using threads instead of subprocesses (and it does deadlock if it replaces _Fork with fork). [1] https://austingroupbugs.net/view.php?id=62
2021-06-23More mcheck -> malloc-check refactoringSiddhesh Poyarekar1-13/+17
Refactored malloc-check rules for tests that are automatically generated and executed with MALLOC_CHECK_=3.
2021-06-22malloc: Drop __malloc_initialized from VersionsSiddhesh Poyarekar1-1/+1
__malloc_initialized is mentioned in Versions when it is actually an internal symbol. The resultant binaries are identical.
2021-06-22tst-mcheck: Rename to tst-malloc-checkSiddhesh Poyarekar2-3/+3
MALLOC_CHECK_ and mcheck() are two different malloc checking features. tst-mcheck does not check mcheck(), instead it checks MALLOC_CHECK_, so rename the file to avoid confusion.
2021-06-03dlfcn: Cleanups after -ldl is no longer requiredFlorian Weimer1-3/+0
This commit removes the ELF constructor and internal variables from dlfcn/dlfcn.c. The file now serves the same purpose as nptl/libpthread-compat.c, so it is renamed to dlfcn/libdl-compat.c. The use of libdl-shared-only-routines ensures that libdl.a is empty. This commit adjusts the test suite not to use $(libdl). The libdl.so symbolic link is no longer installed. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-06-02fix typoXeonacid1-1/+1
"accomodate" should be "accommodate" Reviewed-by: Paul Zimmermann <Paul.Zimmermann@inria.fr>
2021-05-25tst-mallinfo2.c: Use correct multiple for total variableYang Xu1-2/+2
Since test uses 160 multiple for malloc size, we should also use 160 multiple for total variable instead of 16, then comparison is meaningful. So fix it. Also change the ">" to ">=" so that the test is technically valid. Reviewed-by: DJ Delorie <dj@redhat.com>
2021-05-17Missing ENOMEM in realloc_check wrapper (bug 27870)Andreas Schwab2-2/+5
When MALLOC_CHECK_ is non-zero, the realloc hook missed to set errno to ENOMEM when called with too big size. Run the test tst-malloc-too-large also with MALLOC_CHECK_=3 to catch that.
2021-05-16Enable support for GCC 11 -Wmismatched-dealloc.Martin Sebor1-4/+7
To help detect common kinds of memory (and other resource) management bugs, GCC 11 adds support for the detection of mismatched calls to allocation and deallocation functions. At each call site to a known deallocation function GCC checks the set of allocation functions the former can be paired with and, if the two don't match, issues a -Wmismatched-dealloc warning (something similar happens in C++ for mismatched calls to new and delete). GCC also uses the same mechanism to detect attempts to deallocate objects not allocated by any allocation function (or pointers past the first byte into allocated objects) by -Wfree-nonheap-object. This support is enabled for built-in functions like malloc and free. To extend it beyond those, GCC extends attribute malloc to designate a deallocation function to which pointers returned from the allocation function may be passed to deallocate the allocated objects. Another, optional argument designates the positional argument to which the pointer must be passed. This change is the first step in enabling this extended support for Glibc.
2021-05-12Remove all usage of @BASH@ or ${BASH} in installed files, and hardcode ↵Romain GEISSLER2-4/+3
/bin/bash instead (FYI, this is a repost of https://sourceware.org/pipermail/libc-alpha/2019-July/105035.html now that FSF papers have been signed and confirmed on FSF side). This trivial patch attemps to fix BZ 24106. Basically the bash locally used when building glibc on the host shall not leak on the installed glibc, as the system where it is installed might be different and use another bash location. So I have looked for all occurences of @BASH@ or $(BASH) in installed files, and replaced it by /bin/bash. This was suggested by Florian Weimer in the bug report. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-05-11nptl: Move stack cache management, __libpthread_freeres into libcFlorian Weimer1-5/+10
This replaces the FREE_P macro with the __nptl_stack_in_use inline function. stack_list_del is renamed to __nptl_stack_list_del, stack_list_add to __nptl_stack_list_add, __deallocate_stack to __nptl_deallocate_stack, free_stacks to __nptl_free_stacks. It is convenient to move __libpthread_freeres into libc at the same time. This removes the temporary __default_pthread_attr_freeres export and restores full freeres coverage for __default_pthread_attr. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-05-07malloc: Make tunable callback functions staticH.J. Lu1-2/+2
Since malloc tunable callback functions are only used within the same file, we should make them static.
2021-04-21dlfcn: dlerror needs to call free from the base namespace [BZ #24773]Florian Weimer2-7/+5
Calling free directly may end up freeing a pointer allocated by the dynamic loader using malloc from libc.so in the base namespace using the allocator from libc.so in a secondary namespace, which results in crashes. This commit redirects the free call through GLRO and the dynamic linker, to reach the correct namespace. It also cleans up the dlerror handling along the way, so that pthread_setspecific is no longer needed (which avoids triggering bug 24774).
2021-04-12Further fixes for REALLOC_ZERO_BYTES_FREES commentPaul Eggert1-7/+8
* malloc/malloc.c (REALLOC_ZERO_BYTES_FREES): Improve comment further.
2021-04-11Fix REALLOC_ZERO_BYTES_FREES comment to match C17Paul Eggert1-4/+7
* malloc/malloc.c (REALLOC_ZERO_BYTES_FREES): Update comment to match current C standard.
2021-04-07malloc: Run tst-malloc-stats-cancellation via test-driver.cArjun Shankar1-2/+4
This allows the test to time out in case it hangs. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-03-26malloc: Ensure mtag code path in checked_request2size is coldSzabolcs Nagy1-2/+7
This is a workaround (hack) for a gcc optimization issue (PR 99551). Without this the generated code may evaluate the expression in the cold path which causes performance regression for small allocations in the memory tagging disabled (common) case. Reviewed-by: DJ Delorie <dj@redhat.com>
2021-03-26malloc: Remove unnecessary tagging around _mid_memalignSzabolcs Nagy1-8/+2
The internal _mid_memalign already returns newly tagged memory. (__libc_memalign and posix_memalign already relied on this, this patch fixes the other call sites.) Reviewed-by: DJ Delorie <dj@redhat.com>
2021-03-26malloc: Rename chunk2rawmemSzabolcs Nagy2-43/+43
The previous patch ensured that all chunk to mem computations use chunk2rawmem, so now we can rename it to chunk2mem, and in the few cases where the tag of mem is relevant chunk2mem_tag can be used. Replaced tag_at (chunk2rawmem (x)) with chunk2mem_tag (x). Renamed chunk2rawmem to chunk2mem. Reviewed-by: DJ Delorie <dj@redhat.com>
2021-03-26malloc: Use chunk2rawmem throughoutSzabolcs Nagy2-26/+34
The difference between chunk2mem and chunk2rawmem is that the latter does not get the memory tag for the returned pointer. It turns out chunk2rawmem almost always works: The input of chunk2mem is a chunk pointer that is untagged so it can access the chunk header. All memory that is not user allocated heap memory is untagged, which in the current implementation means that it has the 0 tag, but this patch does not rely on the tag value. The patch relies on that chunk operations are either done on untagged chunks or without doing memory access to the user owned part. Internal interface contracts: sysmalloc: Returns untagged memory. _int_malloc: Returns untagged memory. _int_free: Takes untagged memory. _int_memalign: Returns untagged memory. _int_realloc: Takes and returns tagged memory. So only _int_realloc and functions outside this list need care. Alignment checks do not need the right tag and tcache works with untagged memory. tag_at was kept in realloc after an mremap, which is not strictly necessary, since the pointer is only used to retag the memory, but this way the tag is guaranteed to be different from the old tag. Reviewed-by: DJ Delorie <dj@redhat.com>