net/frr[89] revealed an interesting edge-case on arm when dynamically
linking a shared library that declares more than one static TLS variable
with at least one using the "initial-exec" TLS model. In the case
of frr[89], this library was libfrr.so which essentially does the
following:
#include <stdio.h>
#include "lib.h"
static __thread int *a
__attribute__((tls_model("initial-exec")));
void lib_test()
{
static __thread int b = -1;
printf("&a = %p\n", &a);
printf(" a = %p\n", a);
printf("\n");
printf("&b = %p\n", &b);
printf(" b = %d\n", b);
}
Allocates a file scoped `static __thread` pointer with
tls_model("initial-exec") and later a block scoped TLS int. Notice in
the above minimal reproducer, `b == -1`. The relocation process does
the wrong thing and ends up pointing both `a` and `b` at the same place
in memory.
The output of the above in the broken state is:
&a = 0x4009c018
a = 0xffffffff
&b = 0x4009c018
b = -1
With the patch applied, the output becomes:
&a = 0x4009c01c
a = 0x0
&b = 0x4009c018
b = -1
Reviewed by: kib
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D42415/
Forward compatibility code was added for running newer ino64 binaries on
older kernels as a transition aide. Now that ino64 has been in the tree
6 years, this code is no longer useful and should have been removed long
ago. Remove it now. Should be no user-visible changes at this point as
all the 'upgrade' scenarios it was intended for are long since past.
Also need to remove this stuff from rtld since the _foo versions
no longer exist.
Sponsored by: Netflix
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D42382
Add the Branch Target Identification (BTI) note to libc assembly
sources. As all obect files need the note for rtld to have it we need
to insert it in all asm files.
Reviewed by: markj, emaste
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D42228
The new STATIC_TLS_EXTRA variable provides a means for applications
to increases the size of the extra static TLS space allocated by
rtld beyond the default of '128'. This extra static TLS space is used
for objects loaded with dlopen.
The value specified in the variable must be no less than the default
value and no greater than the maximum allowed value for size_t type.
If an invalid value is specified, rtld will ignore it and just use
the default value.
The rtld(1) man page is updated to document this new option.
Obtained from: Juniper Networks, Inc.
Differential Revision: https://reviews.freebsd.org/D42025
Wrong value of ov_index resulted in magic check failure, and refuse to
free() the memory allocated with __crt_aligned_alloc_offset().
Then the TLS segments of exited threads leaked.
Reported and tested by: glebius
Fixes: c29ee08204
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Use regular free(), since it works now.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D41150
It is modelled after aligned_alloc(3). Most importantly, to free the
allocation, __crt_free() can be used. Additionally, caller may specify
offset into the aligned allocation, so that we return offset-ed from
alignment pointer.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D41150
Reorder it with magic, to keep alignment.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D41150
for it to be useful to return unaligned pointer.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D41150
The method might require resolving and binding symbols, which means
recursing on the bind lock. It is safe to unlock the bind lock,
since we operate on the private object list, and user attempting to
unload an object from the list of not yet fully loaded objects caused
self-inflicted race.
It is similar to how we treat user' init/fini methods.
Reported by: stevek
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Note that the pattern for matching is made slightly more specific, so as
to permit libcompats where one is a prefix of another (e.g. CheriBSD has
lib64 and lib64c).
Reviewed by: brooks, jhb, emaste, imp, kib
Differential Revision: https://reviews.freebsd.org/D41183
converting user allocation address into overhead pointer
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D41150
The ovu_magic is not neccessary overlaps with low byte of the ov_next,
for the big endian machines.
There is no range checking in the allocator.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D41150
With ifunc based SIMD dispatch, we cannot use the amd64 assembly
implementations of string functions. Modify rtld to instead use
the generic functions. To avoid an architecture-specific special
case, this change is applied to all architectures.
This change is a prerequisite to and formerly part of D40693.
Sponsored by: FreeBSD Foundation
Approved by: kib
See also: D40693
Differential Revision: https://reviews.freebsd.org/D41050
For instance, dso might be mapped as needed but not yet initialized from
the other subtree of needed objects, while current object' constructor
does dlopen() for the dso. Right now rtld does relocations and other
processing based on the arrival of new objects in the global list, which
is not happens there. Directly check for the initialization state of
the object, for which we would return the handle.
One practical use case of this support is e.g. dlopen("libthr.so",
RTLD_NOLOAD) by libraries that are threading-aware but happy to live
with libc pthread shims if the program is not multithreaded.
Reviewed by: tijl
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Add a stop indicator to rtld_start to satisfy unwinders:
The right unwinding stop indicator should be CFI-undefined PC.
https://dwarfstd.org/doc/Dwarf3.pdf - page 118:
If a Return Address register is defined in the virtual unwind table,
and its rule is undefined (for example, by DW_CFA_undefined), then
there is no return address and no call address, and the virtual
unwind of stack activations is complete.
That is allows gdb and libunwind successfully stop when unwinding stack
from global constructors and destructors.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D40949
Initial stack pointer is preserved in calle-saved %esi,
use it bellow to pass initial stack pointer to _rtld().
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D40950
These are no longer referenced, with the one user of each now using the
double-underscore version with "32" as an argument instead.
Reviewed by: kib, brooks, jhb
Differential Revision: https://reviews.freebsd.org/D40935
We still have a tiny amount of libcompat-specific code in rtld_paths.h,
but it's been deduplicated as much as possible, and in future we may
wish to just push these variables down to the few consumers of them and
make them use the double-underscore variants with a libcompat argument
rather than give them names here.
See commit 8fad2cda93 ("bsd.compat.mk: Provide new CPP and sub-make
variables") for the context behind this change.
Reviewed by: kib, brooks, jhb
Differential Revision: https://reviews.freebsd.org/D40925
1. Add a stop indicator to rtld_start to satisfy unwinders on aarch64:
The right unwinding stop indicator should be CFI-undefined PC.
https://dwarfstd.org/doc/Dwarf3.pdf - page 118:
If a Return Address register is defined in the virtual unwind table,
and its rule is undefined (for example, by DW_CFA_undefined), then
there is no return address and no call address, and the virtual
unwind of stack activations is complete.
2. Add a proper annotations for CFA.
That is allows gdb and libunwind successfully stop when unwinding stack
from global constructors and destructors.
Reviewed by:
Differential Revision: https://reviews.freebsd.org/D40844
Use the LDP (load pair registers) instruction to load entry point
arguments from the stack.
Reviewed by:
Differential Revision: https://reviews.freebsd.org/D40843
The right unwinding stop indicator should be CFI-undefined PC.
https://dwarfstd.org/doc/Dwarf3.pdf - page 118:
If a Return Address register is defined in the virtual unwind table,
and its rule is undefined (for example, by DW_CFA_undefined), then
there is no return address and no call address, and the virtual
unwind of stack activations is complete.
That is allows gdb and libunwind successfully stop when unwinding stack
from global constructors and destructors.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D40794
Some architectures (powerpc and RISC-V) always use 0 for the post TLS
size in which case tls_init_align isn't used by
calculate_tls_post_size. Use __unused to quiet the warning for these
platforms.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D40673
If we are allocating static offset for an object with dynamic index,
return failure. In the opposite case, if dynamic index is requested for
statically allocated TLS area, directly use the offset instead of
setting the index.
Taken from NetBSD Joerg Sonnenberger change for src/libexec/ld.elf_so/tls.c
rev. 1.18.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
The meaning of the flag is that static TLS allocation was done.
Taken from NetBSD Joerg Sonnenberger change for src/libexec/ld.elf_so/tls.c
rev. 1.18.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
The SPDX folks have obsoleted the BSD-2-Clause-NetBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
rtld's Makefile used to add -L${LIBDIR} to LDFLAGS when MK_TOOLCHAIN was
no. This was done as part of a change to fix building rtld with
MK_TOOLCHAIN == no (although I'm not sure this part was necessary).
In any case as of 5f2e84015d libc_pic.a is built independent of the
MK_TOOLCHAIN setting and the main part of the workaround has already
been removed. Remove the rest now.
This reverts commit c0f5aeb032.
Reviewed by: jrtc27
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D39938
Do not terminate scanning group when 'd' is encountered.
The 'b' option must be last in the group, same as 'f'.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D39544
Quoting from https://maskray.me/blog/2023-04-12-elf-hash-function:
The System V Application Binary Interface (generic ABI) specifies the
ELF object file format. When producing an output executable or shared
object needing a dynamic symbol table (.dynsym), a linker generates a
.hash section with type SHT_HASH to hold a symbol hash table. A DT_HASH
tag is produced to hold the address of .hash.
The function is supposed to return a value no larger than 0x0fffffff.
Unfortunately, there is a bug. When unsigned long consists of more than
32 bits, the return value may be larger than UINT32_MAX. For instance,
elf_hash((const unsigned char *)"\xff\x0f\x0f\x0f\x0f\x0f\x12") returns
0x100000002, which is clearly unintended, as the function should behave
the same way regardless of whether long represents a 32-bit integer or
a 64-bit integer.
Reviewed by: kib, Fangrui Song
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D39517
These libraries are linked to directly by applications rather than
opened at runtime via dlopen().
Discussed with: oshogbo
Reviewed by: markj, emaste
Differential Revision: https://reviews.freebsd.org/D39245
Use it instead of defining IN_RTLD by base sources that want P_OSREL_
defines in userspace, but are not rtld.
This allows to remove abuse of IN_RTLD from userspace.
Reviewed by: dchagin, markj, imp
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D38585
After the removal of ia64 and sparc64, all current architectures
support executable stacks at an architectural level.
This reverts commit 1290d38ac5.
Reviewed by: kib
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D37904
similar to the same token in glibc.
Requested and reviewed by: bapt
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D37329
