Age | Commit message (Collapse) | Author | Files | Lines |
|
It is a left-over from commit 52a01100ad011293197637e42b5be1a479a2
("elf: Remove ad-hoc restrictions on dlopen callers [BZ #22787]").
When backporting commmit 6985865bc3ad5b23147ee73466583dd7fdf65892
("elf: Always call destructors in reverse constructor order
(bug 30785)"), we can move the l_init_called_next field to this
place, so that the internal GLIBC_PRIVATE ABI does not change.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
|
|
The current implementation of dlclose (and process exit) re-sorts the
link maps before calling ELF destructors. Destructor order is not the
reverse of the constructor order as a result: The second sort takes
relocation dependencies into account, and other differences can result
from ambiguous inputs, such as cycles. (The force_first handling in
_dl_sort_maps is not effective for dlclose.) After the changes in
this commit, there is still a required difference due to
dlopen/dlclose ordering by the application, but the previous
discrepancies went beyond that.
A new global (namespace-spanning) list of link maps,
_dl_init_called_list, is updated right before ELF constructors are
called from _dl_init.
In dl_close_worker, the maps variable, an on-stack variable length
array, is eliminated. (VLAs are problematic, and dlclose should not
call malloc because it cannot readily deal with malloc failure.)
Marking still-used objects uses the namespace list directly, with
next and next_idx replacing the done_index variable.
After marking, _dl_init_called_list is used to call the destructors
of now-unused maps in reverse destructor order. These destructors
can call dlopen. Previously, new objects do not have l_map_used set.
This had to change: There is no copy of the link map list anymore,
so processing would cover newly opened (and unmarked) mappings,
unloading them. Now, _dl_init (indirectly) sets l_map_used, too.
(dlclose is handled by the existing reentrancy guard.)
After _dl_init_called_list traversal, two more loops follow. The
processing order changes to the original link map order in the
namespace. Previously, dependency order was used. The difference
should not matter because relocation dependencies could already
reorder link maps in the old code.
The changes to _dl_fini remove the sorting step and replace it with
a traversal of _dl_init_called_list. The l_direct_opencount
decrement outside the loader lock is removed because it appears
incorrect: the counter manipulation could race with other dynamic
loader operations.
tst-audit23 needs adjustments to the changes in LA_ACT_DELETE
notifications. The new approach for checking la_activity should
make it clearer that la_activty calls come in pairs around namespace
updates.
The dependency sorting test cases need updates because the destructor
order is always the opposite order of constructor order, even with
relocation dependencies or cycles present.
There is a future cleanup opportunity to remove the now-constant
force_first and for_fini arguments from the _dl_sort_maps function.
Fixes commit 1df71d32fe5f5905ffd5d100e5e9ca8ad62 ("elf: Implement
force_first handling in _dl_sort_maps_dfs (bug 28937)").
Reviewed-by: DJ Delorie <dj@redhat.com>
|
|
In short: __tls_get_addr checks the global generation counter and if
the current dtv is older then _dl_update_slotinfo updates dtv up to the
generation of the accessed module. So if the global generation is newer
than generation of the module then __tls_get_addr keeps hitting the
slow dtv update path. The dtv update path includes a number of checks
to see if any update is needed and this already causes measurable tls
access slow down after dlopen.
It may be possible to detect up-to-date dtv faster. But if there are
many modules loaded (> TLS_SLOTINFO_SURPLUS) then this requires at
least walking the slotinfo list.
This patch tries to update the dtv to the global generation instead, so
after a dlopen the tls access slow path is only hit once. The modules
with larger generation than the accessed one were not necessarily
synchronized before, so additional synchronization is needed.
This patch uses acquire/release synchronization when accessing the
generation counter.
Note: in the x86_64 version of dl-tls.c the generation is only loaded
once, since relaxed mo is not faster than acquire mo load.
I have not benchmarked this. Tested by Adhemerval Zanella on aarch64,
powerpc, sparc, x86 who reported that it fixes the performance issue
of bug 19924.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
|
Parts of elf/tst-rtld-list-diagnostics.py have been copied from
scripts/tst-ld-trace.py.
The abnf module is entirely optional and used to verify the
ABNF grammar as included in the manual.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
|
Otherwise, the ld.so constructor runs for each audit namespace
and each dlmopen namespace.
|
|
These reloc types are generated by GNU assembler >= 2.41 for relaxation
support.
|
|
These reloc types are generated by GNU assembler >= 2.41 for relaxation
support.
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=57a930e3
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
|
|
Leads to build failures (preprocessor redefinitions), and there is not
enough time to address this properly. Deferred until after 2.38 release.
This reverts commit 59dc07637fa1a693bd7599a98b0735697544077b.
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
|
|
Add new definitions for the MIPS target, specifically: relocation
types, machine flags, section type names, and object attribute tags
and values. On MIPS64, up to three relocations may be specified
within r_info, by the r_type, r_type2, and r_type3 fields, so add new
macros to get the respective reloc types for MIPS64.
|
|
Starting with commit 1bcfe0f732066ae5336b252295591ebe7e51c301, the
test was enhanced and the object for __builtin_return_address (0)
is searched with _dl_find_object.
Unfortunately on e.g. s390 (31bit), a postprocessing step is needed
as the highest bit has to be masked out. This can be done with
__builtin_extract_return_addr.
Without this postprocessing, _dl_find_object returns with -1 and the
content of dlfo is invalid, which may lead to segfaults in basename.
Therefore those checks are now only done on success.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
|
|
The sparc ABI has multiple cases on how to handle JMP_SLOT relocations,
(sparc_fixup_plt/sparc64_fixup_plt). For BINDNOW, _dl_audit_symbind
will be responsible to setup the final relocation value; while for
lazy binding _dl_fixup/_dl_profile_fixup will call the audit callback
and tail cail elf_machine_fixup_plt (which will call
sparc64_fixup_plt).
This patch fixes by issuing the SPARC specific routine on bindnow and
forwarding the audit value to elf_machine_fixup_plt for lazy resolution.
It fixes the la_symbind for bind-now tests on sparc64 and sparcv9:
elf/tst-audit24a
elf/tst-audit24b
elf/tst-audit24c
elf/tst-audit24d
Checked on sparc64-linux-gnu and sparcv9-linux-gnu.
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
|
|
Success is reported with a 0 return value, and failure is -1.
Enhance the kitchen sink test elf/tst-audit28 to cover
_dl_find_object as well.
Fixes commit 5d28a8962dcb ("elf: Add _dl_find_object function")
and bug 30515.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
|
|
Add --enable-fortify-source option.
It is now possible to enable fortification through a configure option.
The level may be given as parameter, if none is provided, the configure
script will determine what is the highest level possible that can be set
considering GCC built-ins availability and set it.
If level is explicitly set to 3, configure checks if the compiler
supports the built-in function necessary for it or raise an error if it
isn't.
If the configure option isn't explicitly enabled, it _FORTIFY_SOURCE is
forcibly undefined (and therefore disabled).
The result of the configure checks are new variables, ${fortify_source}
and ${no_fortify_source} that can be used to appropriately populate
CFLAGS.
A dedicated patch will follow to make use of this variable in Makefiles
when necessary.
Updated NEWS and INSTALL.
Adding dedicated x86_64 variant that enables the configuration.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
|
|
The first segment in a shared library may be read-only, not executable.
To support LD_PREFER_MAP_32BIT_EXEC on such shared libraries, we also
check MAP_DENYWRITE to decide if MAP_32BIT should be passed to mmap.
Normally the first segment is mapped with MAP_COPY, which is defined
as (MAP_PRIVATE | MAP_DENYWRITE). But if the segment alignment is
greater than the page size, MAP_COPY isn't used to allocate enough
space to ensure that the segment can be properly aligned. Map the
first segment with MAP_COPY in this case to fix BZ #30452.
|
|
|
|
ldconfig was allocating PATH_MAX bytes on the stack for the library file
name. The issues with PATH_MAX usage are well documented [0][1]; even if
a program does not rely on paths being limited to PATH_MAX bytes,
allocating 4096 bytes on the stack for paths that are typically rather
short (strlen ("/lib64/libc.so.6") is 16) is wasteful and dangerous.
[0]: https://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html
[1]: https://eklitzke.org/path-max-is-tricky
Instead, make use of asprintf to dynamically allocate memory of just the
right size on the heap.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
|
|
With fortification enabled, system calls return result needs to be checked,
has it gets the __wur macro enabled.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
|
|
Sort Makefile variables using scrips/sort-makefile-lines.py.
No code generation changes observed in non-test binary artifacts.
No regressions on x86_64 and i686.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
|
|
|
|
elf/rtld.c is only ever built in SHARED mode.
|
|
Previously, after destructors for a DSO have been invoked, ld.so refused
to bind against that DSO in all cases. Relax this restriction somewhat
if the referencing object is itself a DSO that is being unloaded. This
assumes that the symbol reference is not going to be stored anywhere.
The situation in the test case can arise fairly easily with C++ and
objects that are built with different optimization levels and therefore
define different functions with vague linkage.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
|
|
Applying this commit results in bit-identical libc.so.6.
The elf/ld-linux-x86-64.so.2 does change, but only in .note.gnu.build-id
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
|
|
Linux 6.3 adds constants AT_RSEQ_FEATURE_SIZE and AT_RSEQ_ALIGN; add
them to glibc's elf.h. (Recall that, although elf.h is a
system-independent header, so far we've put AT_* constants there even
if Linux-specific, as discussed in bug 15794. So rather than making
any attempt to fix that issue, the new constants are just added there
alongside the existing ones.)
Tested for x86_64.
|
|
This patch checks _dl_debug_vdprintf, by passing various inputs to
_dl_dprintf and comparing the output with invocations of snprintf.
Signed-off-by: Roy Eldar <royeldar0@gmail.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
|
|
_dl_debug_vdprintf is a bare-bones printf implementation; currently
printing a signed integer (using "%d" format specifier) behaves
incorrectly when the number is negative, as it just prints the
corresponding unsigned integer, preceeded by a minus sign.
For example, _dl_printf("%d", -1) would print '-4294967295'.
Signed-off-by: Roy Eldar <royeldar0@gmail.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
|
|
f55727ca53308a206cf00d0442f8c57c73761899 updated open_path to use the
r_search_path_struct struct but failed to update the comment.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
|
|
When dlopen is being called, efforts have been made to improve
future lookup performance. This includes marking a search path
as non-existent using `stat`. However, if the root directory
is given as a search path, there exists a bug which erroneously
marks it as non-existing.
The bug is reproduced under the following sequence:
1. dlopen is called to open a shared library, with at least:
1) a dependency 'A.so' not directly under the '/' directory
(e.g. /lib/A.so), and
2) another dependency 'B.so' resides in '/'.
2. for this bug to reproduce, 'A.so' should be searched *before* 'B.so'.
3. it first tries to find 'A.so' in /, (e.g. /A.so):
- this will (obviously) fail,
- since it's the first time we have seen the '/' directory,
its 'status' is 'unknown'.
4. `buf[buflen - namelen - 1] = '\0'` is executed:
- it intends to remove the leaf and its final slash,
- because of the speciality of '/', its buflen == namelen + 1,
- it erroneously clears the entire buffer.
6. it then calls 'stat' with the empty buffer:
- which will result in an error.
7. so it marks '/' as 'nonexisting', future lookups will not consider
this path.
8. while /B.so *does* exist, failure to look it up in the '/'
directory leads to a 'cannot open shared object file' error.
This patch fixes the bug by preventing 'buflen', an index to put '\0',
from being set to 0, so that the root '/' is always kept.
Relative search paths are always considered as 'existing' so this
wont be affected.
Writeup by Moody Liu <mooodyhunter@outlook.com>
Suggested-by: Carlos O'Donell <carlos@redhat.com>
Signed-off-by: Qixing ksyx Xue <qixingxue@outlook.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
|
|
Don't strip the trailing slash when checking for existence of a load path
element to handle the special case of the root directory.
|
|
Sort tests against updated scripts/sort-makefile-lines.py.
No changes in generated code.
No regressions on x86_64 and i686.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
|
|
Fix list terminator whitspace.
Sort using scripts/sort-makefile-lines.py.
No code generation changes observed in binary artifacts.
No regressions on x86_64 and i686.
|
|
Avoid inconsistent state in the debugger interface.
|
|
This reverts commit 117e8b341c5c0ace8d65feeef136fececb3fdc9c.
Reason for revert: Causes elf/tst-glibcelf and elf/tst-relro-*
to fail on all architectures.
|
|
In some cases, we do not want to go through the resolver for function
calls. For example, functions with vector arguments will use vector
registers to pass arguments. In the resolver, we do not save/restore the
vector argument registers for lazy binding efficiency. To avoid ruining
the vector arguments, functions with vector arguments will not go
through the resolver.
To achieve the goal, we will annotate the function symbols with
STO_RISCV_VARIANT_CC flag and add DT_RISCV_VARIANT_CC tag in the dynamic
section. In the first pass on PLT relocations, we do not set up to call
_dl_runtime_resolve. Instead, we resolve the functions directly.
Signed-off-by: Hsiangkai Wang <kai.wang@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://inbox.sourceware.org/libc-alpha/20230314162512.35802-1-kito.cheng@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
|
Support for SFrame format is available in Binutils 2.40. The GNU ld merges
the input .sframe sections and creates an output .sframe section in a
segment PT_GNU_SFRAME.
|
|
When opening a temporary file without O_CLOEXEC we risk leaking the
file descriptor if another thread calls (fork and then) exec while we
have the fd open. Fix this by consistently passing O_CLOEXEC everywhere
where we open a file for internal use (and not to return it to the user,
in which case the API defines whether or not the close-on-exec flag
shall be set on the returned fd).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230419160207.65988-4-bugaevc@gmail.com>
|
|
And make always supported. The configure option was added on glibc 2.25
and some features require it (such as hwcap mask, huge pages support, and
lock elisition tuning). It also simplifies the build permutations.
Changes from v1:
* Remove glibc.rtld.dynamic_sort changes, it is orthogonal and needs
more discussion.
* Cleanup more code.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
|
|
Take into account ${sysconfdir} in elf/tst-ldconfig-p.sh.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
|
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
|
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
|
Now that there is no need to use a special linker script to hardening
internal data structures, remove the --with-default-link configure
option and associated definitions.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
|
|
Instead of using a special ELF section along with a linker script
directive to put the IO vtables within the RELRO section, the libio
vtables are all moved to an array marked as data.relro (so linker
will place in the RELRO segment without the need of extra directives).
To avoid static linking namespace issues and including all vtable
referenced objects, all required function pointers are set to weak alias.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
|
|
They are both used by __libc_freeres to free all library malloc
allocated resources to help tooling like mtrace or valgrind with
memory leak tracking.
The current scheme uses assembly markers and linker script entries
to consolidate the free routine function pointers in the RELRO segment
and to be freed buffers in BSS.
This patch changes it to use specific free functions for
libc_freeres_ptrs buffers and call the function pointer array directly
with call_function_static_weak.
It allows the removal of both the internal macros and the linker
script sections.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
|
|
After commit ed3ce71f5c ("elf: Move la_activity (LA_ACT_ADD) after
_dl_add_to_namespace_list() (BZ #28062)") it is no longer necessary to
reset the debugger state in the error case, since the debugger
notification only happens after no more errors can occur.
|
|
|
|
|
|
It was possible to run this test individually and have it fail because
it can't find testobj1.so. This patch adds that dependency, to prevent
such issues.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
|
|
Some toolchains, such as that used on Gentoo Hardened, set -z now out of
the box. This trips up a couple of tests.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
|
|
When mcount overflows, no gmon.out file is generated, but no message is printed
to the user, leaving the user with no idea why, and thinking maybe there is
some bug - which is how BZ 27576 ended up being logged. Print a message to
stderr in this case so the user knows what is going on.
As a comment in sys/gmon.h acknowledges, the hardcoded MAXARCS value is too
small for some large applications, including the test case in that BZ. Rather
than increase it, add tunables to enable MINARCS and MAXARCS to be overridden
at runtime (glibc.gmon.minarcs and glibc.gmon.maxarcs). So if a user gets the
mcount overflow error, they can try increasing maxarcs (they might need to
increase minarcs too if the heuristic is wrong in their case.)
Note setting minarcs/maxarcs too large can cause monstartup to fail with an
out of memory error. If you set them large enough, it can cause an integer
overflow in calculating the buffer size. I haven't done anything to defend
against that - it would not generally be a security vulnerability, since these
tunables will be ignored in suid/sgid programs (due to the SXID_ERASE default),
and if you can set GLIBC_TUNABLES in the environment of a process, you can take
it over anyway (LD_PRELOAD, LD_LIBRARY_PATH, etc). I thought about modifying
the code of monstartup to defend against integer overflows, but doing so is
complicated, and I realise the existing code is susceptible to them even prior
to this change (e.g. try passing a pathologically large highpc argument to
monstartup), so I decided just to leave that possibility in-place.
Add a test case which demonstrates mcount overflow and the tunables.
Document the new tunables in the manual.
Signed-off-by: Simon Kissane <skissane@gmail.com>
Reviewed-by: DJ Delorie <dj@redhat.com>
|
|
While cleaning up old libc version support, the deprecated libc4 code was
accidentally kept in `implicit_soname`, instead of the libc6 code.
This causes additional symlinks to be created by `ldconfig` for libraries
without a soname, e.g. a library `libsomething.123.456.789` without a soname
will create a `libsomething.123` -> `libsomething.123.456.789` symlink.
As the libc6 version of the `implicit_soname` code is a trivial `xstrdup`,
just inline it and remove `implicit_soname` altogether.
Some further simplification looks possible (e.g. the call to `create_links`
looks like a no-op if `soname == NULL`, other than the verbose printfs), but
logic is kept as-is for now.
Fixes: BZ #30125
Fixes: 8ee878592c4a ("Assume only FLAG_ELF_LIBC6 suport")
Signed-off-by: Joan Bruguera <joanbrugueram@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
|
Signed-off-by: Qihao Chencao <twose@qq.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|