_dl_map_object_deps always sorts the initially loaded object first
during dependency sorting. This means it is relocated last in
dl_open_worker. This results in crashes in IFUNC resolvers without
lazy bindings if libraries are preloaded that refer to IFUNCs in
libc.so.6: the resolvers are called when libc.so.6 has not been
relocated yet, so references to _rtld_global_ro etc. crash.
The fix is to check against the libc.so.6 link map recorded by the
__libc_early_init framework, and let it participate in the dependency
sort.
This fixes bug 20972.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Re-mmap executable segments if possible instead of using mprotect
to add PROT_BTI. This allows using BTI protection with security
policies that prevent mprotect with PROT_EXEC.
If the fd of the ELF module is not available because it was kernel
mapped then mprotect is used and failures are ignored. To protect
the main executable even when mprotect is filtered the linux kernel
will have to be changed to add PROT_BTI to it.
The delayed failure reporting is mainly needed because currently
_dl_process_gnu_properties does not propagate failures such that
the required cleanups happen. Using the link_map_machine struct for
error propagation is not ideal, but this seemed to be the least
intrusive solution.
Fixes bug 26831.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To handle GNU property notes on aarch64 some segments need to
be mmaped again, so the fd of the loaded ELF module is needed.
When the fd is not available (kernel loaded modules), then -1
is passed.
The fd is passed to both _dl_process_pt_gnu_property and
_dl_process_pt_note for consistency. Target specific note
processing functions are updated accordingly.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Program headers are processed in two pass: after the first pass
load segments are mmapped so in the second pass target specific
note processing logic can access the notes.
The second pass is moved later so various link_map fields are
set up that may be useful for note processing such as l_phdr.
The second pass should be before the fd is closed so that is
available.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Handle unaligned executable load segments (the bfd linker is not
expected to produce such binaries, but other linkers may).
Computing the mapping bounds follows _dl_map_object_from_fd more
closely now.
Fixes bug 26988.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The _dl_open_check and _rtld_main_check hooks are not called on the
dependencies of a loaded module, so BTI protection was missed on
every module other than the main executable and directly dlopened
libraries.
The fix just iterates over dependencies to enable BTI.
Fixes bug 26926.
Starting with recent commits, I get 43 conform/.../linknamespace FAILs:
- nss: Introduce <nss_module.h>
- <nss_action.h>: New abstraction for combining NSS modules and NSS actions
- nss: Implement <nss_database.h> (see nss/nss_database.c)
- nsswitch: use new internal API (core)
- nsswitch: user new internal API (tests)
- nsswitch: use new internal API (callers)
e.g. conform/XPG42/wordexp.h/linknamespace.out
[initial] wordexp -> [libc.a(wordexp.o)] __getpwnam_r -> [libc.a(getpwnam_r.o)] __nss_database_custom -> [libc.a(nsswitch.o)] __nss_database_get -> [libc.a(nss_database.o)] feof_unlocked
[initial] wordexp -> [libc.a(wordexp.o)] __getpwnam_r -> [libc.a(getpwnam_r.o)] __nss_database_custom -> [libc.a(nsswitch.o)] __nss_database_get -> [libc.a(nss_database.o)] ferror_unlocked
This patch is just using __ferror_unlocked and __feof_unlocked instead of the
non "__" prefixed ones.
Reviewed-by: DJ Delorie <dj@redhat.com>
It removes all the arch-specific assembly implementation. The
outliers are alpha, where its kernel ABI explict return -ENOMEM
in case of failure; and i686, where it can't use
"call *%gs:SYSINFO_OFFSET" during statup in static PIE.
Also some ABIs exports an additional ___brk_addr symbol and to
handle it an internal HAVE_INTERNAL_BRK_ADDR_SYMBOL is added.
Checked on x86_64-linux-gnu, i686-linux-gnu, adn with builsd for
the affected ABIs.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Subdirectories z13, z14, z15 can be selected, mostly based on the
level of support for vector instructions.
Co-Authored-By: Stefan Liebler <stli@linux.ibm.com>
The misattributed dependencies can cause failures in parallel testing
if the dependencies have not been built yet.
Fixes commit a332bd1518
("elf: Add elf/tst-dlopenfail-2 [BZ #25396]").
If glibc is build with -O3 on at least 390 (-m31) or x86 (-m32),
gcc 11 dumps this warning:
svc_tcp.c: In function 'rendezvous_request':
svc_tcp.c:274:3: error: 'memcpy' offset [0, 15] is out of the bounds [0, 0] [-Werror=array-bounds]
274 | memcpy (&xprt->xp_raddr, &addr, sizeof (addr));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
In out-of-memory case, if one of the mallocs in makefd_xprt function
returns NULL, a message is dumped, makefd_xprt returns NULL
and the subsequent memcpy would copy to NULL.
Instead of a segfaulting, we delay a bit (see also __svc_accept_failed
and Bug 14889 (CVE-2011-4609) - svc_run() produces high cpu usage when
accept() fails with EMFILE (CVE-2011-4609).
The same applies to svc_unix.c.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
float_t supposedly represents the type that is used to evaluate float
expressions internally. While the isa supports single-precision float
operations, the port of glibc to s390 incorrectly deferred to the
generic definitions which, back then, tied float_t to double. gcc by
default evaluates float in single precision, so that scenario violates
the C standard (sections 5.2.4.2.2 and 7.12 in C11/C17). With
-fexcess-precision=standard, gcc evaluates float in double precision,
which aligns with the standard yet at the cost of added conversion
instructions.
With this patch, we drop the s390-specific definition of float_t and
defer to the default behavior, which aligns float_t with the
compiler-defined FLT_EVAL_METHOD in a standard-compliant way.
Checked on s390x-linux-gnu with 31-bit and 64-bit builds.
The functions strtoimax, strtoumax, wcstoimax, wcstoumax currently
have three implementations each (wordsize-32, wordsize-64 and dummy
implementation in stdlib/ using #error), defining the functions as
thin wrappers round corresponding *_internal functions. Simplify the
code by changing them into aliases of functions such as strtol and
wcstoull. This is more consistent with how e.g. imaxdiv is handled.
Tested for x86_64 and x86.
Previously, in UCS4 conversion routines we limit the number of
characters we examine to the minimum of the number of characters in the
input and the number of characters in the output. This is not the
correct behavior when __GCONV_IGNORE_ERRORS is set, as we do not consume
an output character when we skip a code unit. Instead, track the input
and output pointers and terminate the loop when either reaches its
limit.
This resolves assertion failures when resetting the input buffer in a step of
iconv, which assumes that the input will be fully consumed given sufficient
output space.
This code manages the mappings of the available databases in NSS
(i.e. passwd, hosts, netgroup, etc) with the actions that should
be taken to do a query on those databases.
This is the main API between query functions scattered throughout
glibc and the underlying code (actions, modules, etc).
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
nss_action manages a set of lists of actions; these are the portions
of the lines in nsswitch.conf to the right of the colons, like
"dns [!UNAVAIL=return] files". Each permutation of actions and
conditionals is cached for reuse, which limits memory growth, and
refers to the static list of modules managed by nss_modules.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This provides the struct nss_module type, which combines the old
struct service_library type with the known_function tree, by
statically allocating space for all function pointers.
struct nss_module is fairly large (536 bytes), but it will be
shared across NSS databases. The old known_function handling
had non-some per-function overhead (at least 32 bytes per looked-up
function, but more for long function anmes), so overall, this is not
too bad. Resolving all functions at load time simplifies locking,
and the repeated lookups should be fast because the caches are hot
at this point.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Check HAS_CPU_FEATURE instead of CPU_FEATURE_USABLE for FSGSBASE, IBT,
LM, SHSTK and XSAVES since FSGSBASE requires kernel support, IBT/SHSTK/LM
require OS support and XSAVES is supervisor-mode only.
Following macros: lll_futex_timed_lock_pi, lll_futex_clock_wait_bitset,
lll_futex_wait_requeue_pi, lll_futex_timed_wait_requeue_pi are not
used anymore so are eligible for removal.
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
After gai_suspend and aio_suspend conversion to support 64 bit time and
hence rewriting the code to use only absolute variants of futex wait
functions (i.e. __futex_abstimed_wait64 and __futex_abstimed_wait_cancelable64)
futex_reltimed_wait{_cancelable} are not needed anymore and can be removed.
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
This change uses (in gai_misc.h):
- __futex_abstimed_wait64 (instead of futex_reltimed_wait)
- __futex_abstimed_wait_cancellable64
(instead of futex_reltimed_wait_cancellable)
from ./sysdeps/nptl/futex-helpers.h
The gai_suspend() accepts relative timeout, which then is converted to
absolute one.
The i686-gnu port (HURD) do not define DONT_NEED_GAI_MISC_COND and as it
doesn't (yet) support 64 bit time it uses not converted
pthread_cond_timedwait().
The __gai_suspend() is supposed to be run on ports with __TIMESIZE !=64 and
__WORDSIZE==32. It internally utilizes __gai_suspend_time64() and hence the
conversion from 32 bit struct timespec to 64 bit one is required.
For ports supporting 64 bit time the __gai_suspend_time64() will be used
either via alias (to __gai_suspend when __TIMESIZE==64) or redirection
(when -D_TIME_BITS=64 is passed).
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
The __gai_suspend_time64, which supports 64 bit time on ports with
__WORDSIZE == 32 && __TIMESIZE != 64, shall be exported from libanl
(the same library from which original gai_suspend is exported).
Up till now there were no defines for this library. This commit adds
them.
This recognizes the DL_CACHE_HWCAP_EXTENSION flag in cache entries,
and picks the supported cache entry with the highest priority.
The elf/tst-glibc-hwcaps-prepend-cache test documents a non-desired
aspect of the current cache implementation: If the cache selects a DSO
that does not exist on disk, _dl_map_object falls back to open_path,
which may or may not find an alternative implementation. This is an
existing limitation that also applies to the legacy hwcaps processing
for ld.so.cache.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Libraries from these subdirectories are added to the cache
with a special hwcap bit DL_CACHE_HWCAP_EXTENSION, so that
they are ignored by older dynamic loaders.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This simplifies the string table construction in elf/cache.c
because there is no more need to keep track of offsets explicitly;
the string table implementation does this internally.
This change slightly reduces the size of the cache on disk. The
file format does not change as a result. The strings are
null-terminated, without explicit length, so tail merging is
transparent to readers.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This will be used in ldconfig to reduce the ld.so.cache size slightly.
Tail merging is an optimization where a pointer points into another
string if the first string is a suffix of the second string.
The hash function FNV-1a was chosen because it is simple and achieves
good dispersion even for short strings (so that the hash table bucket
count can be a power of two). It is clearly superior to the hsearch
hash and the ELF hash in this regard.
The hash table uses chaining for collision resolution.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
A previously unused new-format header field is used to record
the address of an extension directory.
This change adds a demo extension which records the version of
ldconfig which builds a file.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Use a reserved byte in the new format cache header to indicate whether
the file is in little endian or big endian format. Eventually, this
information could be used to provide a unified cache for qemu-user
and similiar scenarios.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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>
The previous definition of THREAD_SELF did not tell the compiler
that %fs (or %gs) usage is invalid for the !DL_LOOKUP_GSCOPE_LOCK
case in _dl_lookup_symbol_x. As a result, ld.so could try to use the
TCB before it was initialized.
As the comment in tls.h explains, asm volatile is undesirable here.
Using the __seg_fs (or __seg_gs) namespace does not interfere with
optimization, and expresses that THREAD_SELF is potentially trapping.
