This patch fixes dlfcn/tststatic5 for PowerPC where pagesize
variable was not properly initialized in certain cases. This patch
is based on other architecture code.
The helper binary pt_chown tricked into granting access to another
user's pseudo-terminal.
Pre-conditions for the attack:
* Attacker with local user account
* Kernel with FUSE support
* "user_allow_other" in /etc/fuse.conf
* Victim with allocated slave in /dev/pts
Using the setuid installed pt_chown and a weak check on whether a file
descriptor is a tty, an attacker could fake a pty check using FUSE and
trick pt_chown to grant ownership of a pty descriptor that the current
user does not own. It cannot access /dev/pts/ptmx however.
In most modern distributions pt_chown is not needed because devpts
is enabled by default. The fix for this CVE is to disable building
and using pt_chown by default. We still provide a configure option
to enable hte use of pt_chown but distributions do so at their own
risk.
The generated header is compiled with `-ffreestanding' to avoid any
circular dependencies against the installed implementation headers.
Such a dependency would require the implementation header to be
installed before the generated header could be built (See bug 15711).
In current practice the generated header dependencies do not include
any of the implementation headers removed by the use of `-ffreestanding'.
---
2013-07-15 Carlos O'Donell <carlos@redhat.com>
[BZ #15711]
* sysdeps/unix/sysv/linux/Makefile ($(objpfx)bits/syscall%h):
Avoid system header dependency with -ffreestanding.
($(objpfx)bits/syscall%d): Likewise.
This change creates a link map in static executables to serve as the
global search list for dlopen. It fixes a problem with the inability
to access the global symbol object and a crash on an attempt to map a
DSO into the global scope. Some code that has become dead after the
addition of this link map is removed too and test cases are provided.
Many Linux arches require fixed mmaps to be aligned higher than pagesize,
so use the SHMLBA define as it represents this quantity exactly.
This fixes spurious errors seen on those arches like:
cannot map archive header: Invalid argument
URL: http://sourceware.org/bugzilla/show_bug.cgi?id=10283
Reported-by: CHIKAMA Masaki <masaki.chikama@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Rather than open coding the masks, add helper macros to do the magic.
This makes code easier to read.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Check wheter the compiler has the option -fno-tree-loop-distribute-patterns
to inhibit loop transformation to library calls and uses it on memset
and memmove default implementation to avoid recursive calls.
This patch introduces two new convenience functions to set the default
thread attributes used for creating threads. This allows a programmer
to set the default thread attributes just once in a process and then
run pthread_create without additional attributes.
GCC 4.8 enables -ftree-loop-distribute-patterns at -O3 by default and
this optimization may transform loops into memset/memmove calls. Without
proper handling this may generate unexpected PLT calls on GLIBC.
This patch fixes by create memset/memmove alias to internal GLIBC
__GI_memset/__GI_memmove symbols.
The most common use case of math functions is with default rounding
mode, i.e. rounding to nearest. Setting and restoring rounding mode
is an unnecessary overhead for this, so I've added support for a
context, which does the set/restore only if the FP status needs a
change. The code is written such that only x86 uses these. Other
architectures should be unaffected by it, but would definitely benefit
if the set/restore has as much overhead relative to the rest of the
code, as the x86 bits do.
Here's a summary of the performance improvement due to these
improvements; I've only mentioned functions that use the set/restore
and have benchmark inputs for x86_64:
Before:
cos(): ITERS:4.69335e+08: TOTAL:28884.6Mcy, MAX:4080.28cy, MIN:57.562cy, 16248.6 calls/Mcy
exp(): ITERS:4.47604e+08: TOTAL:28796.2Mcy, MAX:207.721cy, MIN:62.385cy, 15543.9 calls/Mcy
pow(): ITERS:1.63485e+08: TOTAL:28879.9Mcy, MAX:362.255cy, MIN:172.469cy, 5660.86 calls/Mcy
sin(): ITERS:3.89578e+08: TOTAL:28900Mcy, MAX:704.859cy, MIN:47.583cy, 13480.2 calls/Mcy
tan(): ITERS:7.0971e+07: TOTAL:28902.2Mcy, MAX:1357.79cy, MIN:388.58cy, 2455.55 calls/Mcy
After:
cos(): ITERS:6.0014e+08: TOTAL:28875.9Mcy, MAX:364.283cy, MIN:45.716cy, 20783.4 calls/Mcy
exp(): ITERS:5.48578e+08: TOTAL:28764.9Mcy, MAX:191.617cy, MIN:51.011cy, 19071.1 calls/Mcy
pow(): ITERS:1.70013e+08: TOTAL:28873.6Mcy, MAX:689.522cy, MIN:163.989cy, 5888.18 calls/Mcy
sin(): ITERS:4.64079e+08: TOTAL:28891.5Mcy, MAX:6959.3cy, MIN:36.189cy, 16062.8 calls/Mcy
tan(): ITERS:7.2354e+07: TOTAL:28898.9Mcy, MAX:1295.57cy, MIN:380.698cy, 2503.7 calls/Mcy
So the improvements are:
cos: 27.9089%
exp: 22.6919%
pow: 4.01564%
sin: 19.1585%
tan: 1.96086%
The downside of the change is that it will have an adverse performance
impact on non-default rounding modes, but I think the tradeoff is
justified.
This is the initial support for string function performance tests,
along with copying tests for memcpy and memcpy-ifunc as proof of
concept. The string function benchmarks perform operations at
different alignments and for different sizes and compare performance
between plain operations and the optimized string operations. Due to
this their output is incompatible with the function benchmarks where
we're interested in fastest time, throughput, etc.
In future, the correctness checks in the benchmark tests can be
removed. Same goes for the performance measurements in the
string/test-*.
__clock_gettime and other __clock_* functions could result in an extra
PLT reference within libc.so if it actually gets used. None of the
code currently uses them, which is why this probably went unnoticed.
When setting BENCH_DURATION in CPPFLAGS-nonlib, append to the variable
instead of assigning to it, to avoid overwriting earlier set flags,
notably the -DNOT_IN_libc=1 flag.
In 128-bit IBM long double the precision of the type
decreases as you approach subnormal numbers, equaling
that of a double for subnormal numbers. Therefore
adjust the computation in ulp to use 2^(MIN_EXP - MANT_DIG)
which is correct for FP_SUBNORMAL for all types.
Resolves: #15465
The program name may be unavailable if the user application tampers
with argc and argv[]. Some parts of the dynamic linker caters for
this while others don't, so this patch consolidates the check and
fallback into a single macro and updates all users.
Added descriptive titles to the Belarusian,
English (American), and Chinese (simplified)
po/pot files.
---
2013-05-28 Carlos O'Donell <carlos@redhat.com>
* po/be.po: Add descriptive title.
* po/zh_CN.po: Likewise.
* po/header.pot: Likewise.
When mkstemp fails, the error message the user gets back is:
cannot create temporary file: No such file or directory
That isn't terribly useful in figuring out why, so include the full
filename we tried to create in the error output.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
It is the magnitude of the return value which lies
in [0.5, 1), not the return value itself.
---
2013-05-28 Ben North <ben@redfrontdoor.org>
* manual/arith.texi (frexp): It is the magnitude of the return
value which lies in [0.5, 1), not the return value itself.
The current value used for ulp near zero is wrong,
and this commit fixes it such that ulp(0) is the smallest
subnormal value nearest to zero, which makes the most
sense for testing values near zero. Note that this is not
what Java does; they use the nearest normal value, which
is less accurate than what we want for glibc. Note that
there is no correct implementation of ulp since there
is no strict mathmatical definition that is accepted by
all groups using IEEE 754.
Previously with the large ulp values near zero there
were tests that previously passed, but were in fact
billions of ulp away from the precise answer. With this
commit we now need to disable one of the cpow tests which
is revealed to be inaccurate (bug 14473).
---
2013-05-24 Carlos O'Donell <carlos@redhat.com>
* math/libm-test.inc (MAX_EXP): Define.
(ULPDIFF): Define.
(ulp): New function.
(check_float_internal): Use ULPDIFF.
(cpow_test): Disable failing test.
(check_ulp): Test ulp() implemetnation.
(main): Call check_ulp before starting tests.
Fixes 15381.
Using wide character function is on byte oriented memstream is undefined
behaviour. This behaviour was masked by not initializing wide struct
info. We now initialize it to cause a predictable crash.
In dl-hwcaps.c the comment read that rounding was done
to ElfW(Addr), but it's actually rounded to ElfW(Word).
In ldconfig.c we make each comment a sentence and
mention that the "tls" pseudo-hwcap is just for legacy
installations where TLS was optional.
---
2013-05-22 Carlos O'Donell <carlos@redhat.com>
* elf/ldconfig.c (is_hwcap_platform): Make comments full setences.
(main): Mention "tls" pseudo-hwcap is legacy.
* elf/dl-hwcaps.c (_dl_important_hwcaps): Correct rounding comment.
This patch fixes two issues, and perhaps should be two distinct commits,
but I present it here as one for the sake of completeness.
Commit 006dd86111 fails to check malloc's
return in intl/dcigettext.c (_nl_find_msg):
~~~
freemem_size = INITIAL_BLOCK_SIZE;
newmem = (transmem_block_t *) malloc (freemem_size);
...
newmem->next = transmem_list;
transmem_list = newmem;
~~~
If malloc fails then newmem is NULL then newmem->next results in a
fault.
The fix is easy enough, check for newmem != NULL, and fall through to
the error condition below which returns (char *) -1 e.g. resource error.
The problem is that returning (char *) -1 will break all sorts of other
code, so while what we did is correct, the real failure case fix is
slightly broader.
There are 4 other places where _nl_find_msg is called, one is OK, the
other three are fixed to handle -1 error return value.
No regressions on x86-64 or x86.
However, no regressions isn't really a useful metric for this code.
The change was tested as documented here:
http://sourceware.org/glibc/wiki/Testing/WhiteBox
using SystemTap for fault injection to simulate malloc failure.
---
2013-05-03 Carlos O'Donell <carlos at redhat.com>
[BZ #15441]
* intl/dcigettext.c (DCIGETTEXT): Skip translating if _nl_find_msg
returns -1.
(_nl_find_msg): Return -1 if recursive call returned -1. If newmem is
null return -1.
* intl/loadmsgcat.c (_nl_load_domain): If _nl_find_msg returns -1 abort
loading the domain.
This helps testing for regression of BZ#15339. Creation of network
isolated environments is a privileged operation and therefore is not
included to the test.
Fixes BZ #15339.
NSS_STATUS_UNAVAIL may mean that a necessary input resource is not
available. This could occur in a number of cases including when the
network is down, system runs out of file descriptors, etc. The
correct differentiator in such a case is the h_errno, which gives the
nature of failure. In case of failures other than a simple 'not
found', we set h_errno as NETDB_INTERNAL and let errno be the
identifier for the exact error.
This implementation speed up memset in several ways. First is avoiding
expensive computed jump. Second is using fact that arguments of memset
are most of time aligned to 8 bytes.
Benchmark results on:
kam.mff.cuni.cz/~ondra/benchmark_string/memset_profile_result27_04_13.tar.bz2
We add new memcpy version that uses unaligned loads which are fast
on modern processors. This allows second improvement which is avoiding
computed jump which is relatively expensive operation.
Tests available here:
http://kam.mff.cuni.cz/~ondra/memcpy_profile_result27_04_13.tar.bz2
Resolves: #15424
The compiler would optimize the benchmark function call out of the
loop and call it only once, resulting in blazingly fast times for some
benchmarks (notably atan, sin and cos). Mark the inputs as volatile
so that the code is forced to read again from the input for each
iteration.
