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linux commit 7bb7f2ac24a028b20fca466b9633847b289b156a
arch, mm: wire up memfd_secret system call where relevant
linux commit 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49
mm: introduce memfd_secret system call to create "secret" memory areas
linux commit b633896314c0f78f2b4eb7b19a530d68f2a35445
tools headers UAPI: Sync s390 syscall table file that wires up the
memfd_secret syscall
this commit should make no codegen change for existing archs, but is a
prerequisite for new archs including riscv32. the wait4 emulation
backend provides both cancellable and non-cancellable variants because
waitpid is required to be a cancellation point, but all of our other
uses are not, and most of them cannot be.
based on patch by Stefan O'Rear.
commit f47a5d400b overlooked that
strtoul was responsible for setting p to a const-laundered copy of the
format string pointer f, even in the case where there was no number to
parse. by making the call conditional on isdigit, that copy was lost.
the logic here is a mess and should be cleaned up, but for now, this
seems to be the least invasive change that undoes the breakage.
commit f247462b08 incorrectly hid ppoll
in the presence of _GNU_SOURCE due to an oversight that defining
_BSD_SOURCE does not implicitly define _GNU_SOURCE. at present,
headers still have to explicitly check for each feature profile level;
this may be changed at some point in the future via features.h, but
has not been changed yet.
depending on contents of the LC_TIME locale, log messages could be
malformatted (especially if the ABMON strings contain non-alphabetic
characters) or the subsequent code could invoke undefined behavior,
via passing a timebuf[] with unspecified contents to snprintf, if
the translated ABMON string did not fit in the 16-byte timebuf.
this does not appear to be a security-relevant bug, as locale loading
functionality is intentionally not available to set*id programs -- the
MUSL_LOCPATH environment variable is ignored when libc.secure is true,
and custom locales are not loadable without it.
Undefine any previous __STDC_UTF_{16,32}__ macros before defining
them to prenvent any warnings of redefining macros.
This happens as a result of some compiler versions defining the macros
themselves.
Linux and most systems do not have symlink permissions, but some
systems, including MacOS, do, and creation of the symlink with umask
set to 0777 makes the symlink inaccessible on such systems.
clear umask when making a symlink so that the behavior is uniform.
having these constants be static was unnecessary, so just remove the
static.
this error should have been caught by compilers, but recent versions
of both gcc and clang accept these as "other forms of constant
expressions" which the C standard allows.
Previously, __riscv_flush_icache would not work correctly as
__vdso_flush_icache had a wrong symbol version. Fix this by correcting
symbol version.
Fixes: 0a48860c27 ("add riscv64 architecture support")
Note: Some relocation types were only used by binutils and
accidentally exposed to previous versions of psABI. One of the values
has been reused by GOT32_PCREL.
the ppoll function has been accepted as a future part of the standard
as the outcome of Austin Group tracker issue 1263. at some point it
should be exposed unconditionally, but for now, expose it in the
default feature profile.
the ppoll function has been accepted as a future part of the standard
as the outcome of Austin Group tracker issue 1263. move the source
file to reflect this.
this was a POSIX requirement that was always in conflict with ISO C,
which specified a well-defined behavior for snprintf and swprintf so
long as the actual number of bytes/characters produced did not exceed
INT_MAX.
I originally raised this conflict for snprintf with the Austin Group
as tracker issue 761, which was never resolved. it was later reported
again as issue 1219, and as a result the conflicting requirement has
been removed.
the corresponding issue with swprintf does not seem to have been
addressed, but as the same reasoning applies to it, I am removing the
limitation on n for swprintf as well.
strtoul will consume leading whitespace or sign characters, which are
not valid in this context, thereby accepting invalid field specifiers.
so, avoid calling it unless there is a number to parse as the width.
this matters because the kernel-provided mtab only escapes tabs,
spaces, newlines, and backslashes. it leaves carriage returns, form
feeds, and vertical tabs literal.
As entries in mtab are delimited by spaces, whitespace characters
are escaped as octal sequences. When reading them out, we have to
unescape these sequences to get the proper string.
presently this only affects 32-bit arm. despite correctly reversing
the function pointer and argument fields based on the
TLSDESC_BACKWARDS macro, we did not read the addend from the
swapped-order argument field, so nonzero addends were lost, producing
wrong runtime addresses for TLS objects needing an addend.
based on report and patch by Rui Ueyama.
this is contrary to the spec as written, which requires %lc to behave
as if it were %ls on a 2-wchar_t buffer containing the argument and
zero. however, apparently no other implementations conform to the spec
as written, and in response to Austin Group issue #1647, WG14 chose to
align with existing practice and have %lc produce output for this case.
The name resolution would abort when getting more than 63 records per
request, due to what seems to be a left-over from the original code.
This check was non-breaking but spurious prior to TCP fallback
support, since any 512-byte packet with more than 63 records was
necessarily malformed. But now, it wrongly rejects valid results.
Reported by Daniel Stefanik in Alpine Linux aports issue 15320.
AT_NO_AUTOMOUNT is implied for stat/lstat/fstatat syscalls since Linux
3.1 (commit b6c8069d3577481390b3f24a8434ad72a3235594). However, this
is not the case for statx syscall, which defaults to automounting, so
this flag must be passed explicitly when statx is used to implement
stat-like functions.
This change affects only arches which use 32-bit seconds in struct kstat,
as well as out-of-tree/future ports to arches which lack SYS_fstatat.
C11 6.11.5p1:
> The placement of a storage-class specifier other than at the
> beginning of the declaration specifiers in a declaration is an
> obsolescent feature.
gcc also warns about this.
If __synccall() fails to capture all threads because tkill fails for
some reason other than EAGAIN, then the callback given will never be
executed, so nothing will ever overwrite the initial value. So that is
the value that will be returned from the function. The previous setting
of 1 is not a valid value for setuid() et al. to return.
I chose -EAGAIN since I don't know the reason the synccall failed ahead
of time, but EAGAIN is a specified error code for a possibly temporary
failure in setuid().
The code intends for the sem_post() in line 97 (now 98) to only unblock
target threads waiting on line 29. But after the first thread is
released, the next sem_post() might also unblock a thread waiting on
line 36. That would cause the thread to return to the execution of user
code before all threads are done, leading to user code being executed in
a mixed-credentials environment.
What's more, if this happens more than once, then the mass release on
line 110 (now line 111) will cause multiple threads to execute the
callback at the same time, and the callbacks are currently not written
to cope with that situation.
Adding another semaphore allows the caller to say explicitly which
threads it wants to release.
previously, the relative load address was used as the address at which
to find the ELF headers. this only works if two conditions are met:
ldso is linked to start at a virtual address of 0, and the linker is
cooperative and includes the main ELF headers in a loadable segment.
while in practice these are always met, modern linkers provide a
__ehdr_start symbol pointing to the ELF headers, and can in principle
use the reference to this symbol as an indication that they need to be
mapped in a segment. this also should make it possible to link for a
different starting virtual address, if that's ever desirable.
commit 37bb3cce45 suppressed the
declaration for C++, where it is wrongly interpreted as declaring the
function as taking no arguments. with C23 removing non-prototype
declarations, that problem is now also relevant to C.
the non-prototype declaration for basename originates with commit
06aec8d715, where it was designed to
avoid conflicts with programs which declare basename with the GNU
signature taking const char *. that change was probably misguided, as
it represents not only misaligned expectations with the caller, but
also undefined behavior (calling a function that's been declared with
the wrong type).
we could opt to fix the declaration, but since glibc, with the
gratuitously incompatible GNU-basename function, seems to be the only
implementation that declares it in string.h, it seems better to just
remove the declaration. this provides some warning if applications are
being built expecting the GNU behavior but not getting it. if we
declared it here, it would only produce a warning if the caller also
declares it themselves (rare) or if the caller attempts to pass a
const-qualified pointer.
These were overlooked when DT_RELR was added in commit
d32dadd60e, potentially breaking
software that treats presence of the DT_RELR macro as implying they
exist.
when the result count was zero, glob was ignoring a possible
GLOB_ABORTED error code and returning GLOB_NOMATCH. whether this
happened could be nondeterministic and dependent on the order of
dirent enumeration, in cases where multiple matches were present and
only some produced errors.
caught by Tor's test_util_glob.
This is the only missing part in struct statvfs. The LSB calls
[f]statfs() deprecated, and its weird types are definitely
off-putting. However, its use is required to get f_type.
Instead, allocate one of the six spares to f_type, copied directly
from struct statfs. This then becomes a small extension to the
standard interface on Linux, instead of two different interfaces, one
of which is quite odd due to being an ABI type, and there no longer is
any reason to use statfs().
The underlying kernel type is a mess, but all architectures agree on u32
(or more) for the ABI, and all filesystem magicks are 32-bit integers.
Since commit 6567db65f4 (prior to
1.0.0), the spare slots have been zero-filled, so on all versions that
may be reasonably be encountered in the wild, applications can rely on
a nonzero f_type as indication that the new field has been filled in.
powl used >= LDBL_MAX as infinity check, but LDBL_MAX is finite, so
this can cause wrong results e.g. powl(LDBL_MAX, 0.5) returned inf
or powl(2, LDBL_MAX) returned inf without raising overflow.
huge y values (close to LDBL_MAX) could cause intermediate results to
overflow (computing y * log2(x) with more than long double precision)
and e.g. powl(0.5, 0x1p16380L) or powl(10, 0x1p16380L) returned nan.
this is fixed by handling huge y early since that always overflows or
underflows.
reported by Paul Zimmermann against expl10 (which uses powl).
acosh(x) is nan for x < 1, but x < 0 cases were not handled specially
and acoshl gave wrong result for some -0x1p32 < x < -2 values, e.g.:
acoshl(-0x1p20) returned -inf,
acoshl(-0x1.4p20) returned -0x1.db365758403aa9acp+0L,
fixed by checking the sign bit and handling it specially.
reported by Paul Zimmermann.
the __dns_parse code used by the stub resolver traditionally included
code to reject label pointers to offsets past a 512 byte limit,
despite never processing the label contents, only stepping over them.
when commit 51d4669fb9 added support for
tcp fallback, this limit was overlooked, and as a result, it was at
least theoretically possible for some valid large answers to be
rejected on account of these offsets.
since the limit was never serving any useful purpose, just remove it.
in the event of chained CNAMEs, the answer to a query will contain the
entire CNAME chain, not just one CNAME record. previously, the answer
buffer size had been chosen to admit a maximal-length CNAME, but only
one. a moderate-length chain could fill the available 768 bytes
leaving no room for an actual address answering the query.
while the DNS RFCs do not specify any limit on the length of a CNAME
chain, or any reasonable behavior is the chain exceeds the entire 64k
possible message size, actual recursive servers have to impose a
limit, and a such, for all practical purposes, chains longer than this
limit are not usable. it turns out BIND has a hard-coded limit of 16,
and Unbound has a default limit of 11.
assuming the recursive server makes use of "compression" (pointers),
each maximal-length CNAME record takes at most 268 bytes, and thus any
chain up to length 16 fits in at most 4288 bytes.
this patch increases the answer buffer size to preserve the original
intent of having 512 bytes available for address answers, plus space
needed for a maximal CNAME chain, for a total of 4800 bytes. the
resulting size of 9600 bytes for two queries (A+AAAA) is still well
within what is reasonable to place in automatic storage.
the extra terms 3 and LDBL_MANT_DIG/4 are remnants of a proto-musl
implementation of printf where the sign/prefix and floating point
conversions were performed naively into this buffer. having them there
obscures the actual intended buffer size (sufficient to hold between 2
and 3 octal digits per byte, rounded up to 3 for simplicity) and
interferes with upcoming work to add C2x binary formats which would
otherwise be stuck having to explain a similar fix to buffer size as
part of an unrelated change.
%c takes an argument of type int, not char, and %lc/%C takes an
argument of type wint_t (unsigned), not int.
for most cases, this makes no practical difference, but since wide
printf variants convert narrow %c format specifiers via btowc,
interpreting the promoted-to-int unsigned char value passed in as a
(signed, on most archs) char causes 255 to get collapsed to EOF and
interpreted as such by btowc.
this is only relevant in the byte-based C locale, so prior to commit
f22a9edaf8, there was no observable
distinction in behavior. for UTF-8, all bytes which might be negative
when interpreted as char are encoding errors when used with %c/btowc.
the clone() function has been effectively unusable since it was added,
due to producing a child process with inconsistent state. in
particular, the child process's thread structure still contains the
tid, thread list pointers, thread count, and robust list for the
parent. this will cause malfunction in interfaces that attempt to use
the tid or thread list, some of which are specified to be
async-signal-safe.
this patch attempts to make clone() consistent in a _Fork-like sense.
as in _Fork, when the parent process is multi-threaded, the child
process inherits an async-signal context where it cannot call
AS-unsafe functions, but its context is now intended to be safe for
calling AS-safe functions. making clone fork-like would also be a
future option, if it turns out that this is what makes sense to
applications, but it's not done at this time because the changes would
be more invasive.
in the case where the CLONE_VM flag is used, clone is only vfork-like,
not _Fork-like. in particular, the child will see itself as having the
parent's tid, and cannot safely call any libc functions but one of the
exec family or _exit.
handling of flags and variadic arguments is also changed so that
arguments are only consumed with flags that indicate their presence,
and so that flags which produce an inconsistent state are disallowed
(reported as EINVAL). in particular, all libc functions carry a
contract that they are only callable with ABI requirements met, which
includes having a valid thread pointer to a thread structure that's
unique within the process, and whose contents are opaque and only able
to be setup internally by the implementation. the only way for an
application to use flags that violate these requirements without
executing any libc code is to perform the syscall from
application-provided asm.
apparently Linux clears the registered exit futex address on fork.
this means that, if after forking the child process becomes
multithreaded and the original thread exits, the thread list will
never be unlocked, and future attempts to use the thread list will
deadlock.
re-register the exit futex address after _Fork in the child to ensure
that it's preserved.
mbrtowc truncates n to unsigned int when storing its copy.
If n > UINT_MAX and the locale is not POSIX, the function will
return a wrong value greater than UINT_MAX on the success path.
aside from the documented differences, which are the contents of this
patch, GCC's -Os also has hard-coded unwanted behaviors which are
impossible to override, like refusing to strength-reduce division by a
constant to multiplication, presumably because the div saves a couple
bytes of code. for this reason, getting rid of -Os and switching to an
equivalent default optimization profile based on -O2 has been a
long-term goal.
as follow-ups, it may make sense to evaluate which of these variations
from -O2 actually do anything useful, and eliminate the ones which are
not helpful or which throw away performance for insignificant size
savings. but for now, I've replicated -Os as closely as possible to
provide a baseline for such evaluation.
The nl_type and nl_arg arrays defined in vfwprintf may be accessed
with an index up to and including NL_ARGMAX, but they are only of size
NL_ARGMAX, meaning they may be written to or read from 1 element too
far.
Resource usage data is filled by the kernel only when wait4 returns
a pid, i.e. a positive value.
Commit 5850546e96 introduced this bug,
possibly because of copy-pasting from getrusage.
Gaël PORTAY
Rich Felker
Hongliang Wang
Jules Maselbas
Tim Cuthbertson
gns
Elliott Hughes
Fangrui Song
q66
Quentin Rameau
Alexey Izbyshev
Alex Xu (Hello71)
Markus Wichmann
Violet Purcell
наб
Szabolcs Nagy
Gabriel Ravier