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-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
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
To allow for a dynamic page size on arm64 have the runtime linker
query the kernel for the currentl page size.
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D34765
lld rounds up p_memsz(PT_GNU_RELRO) to satisfy common-page-size. If the
page size is smaller than common-page-size, rounding up relro_size may
incorrectly make some RW pages read-only.
GNU ld, gold, and ld.lld ensures p_vaddr+p_memsz is a multiple of
common-page-size. While max-page-size >= system the page size,
common-page-size can be smaller than the system page size.
Submitted by: MaskRay
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31498
See https://sourceware.org/bugzilla/show_bug.cgi?id=24606 for the test case.
See https://reviews.llvm.org/D64930 for the background and more discussion.
Also this fixes another bug in malloc_aligned() where total size of
the allocated memory might be not enough to fit the aligned requested
block after the initial pointer is incremented by the pointer size.
Reviewed by: bdragon
Tested by: antoine (exp-run PR 244866), bdragon, emaste
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D21163
When a PT_LOAD segment has a zero p_filesz, skip the data mmap, as mmapping
zero bytes from a file is an error.
A PT_LOAD with zero p_filesz is legal (but somewhat uncommon due to segment
merging in modern linkers, as it is more efficient to merge .data and .bss
by just extending p_memsz in the previous segment, assuming compatible
page protection.)
This was seen on ports/graphics/glew on a powerpc64 ELFv2 experimental
build.
Submitted by: Alfredo Dal'Ava Junior <alfredo.junior@eldorado.org.br>
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D22634
It is unused after r340102, and more important, I do not see how to
define textsize in both practically useful and correct way, for binaries
with more that one executable segments.
Sponsored by: The FreeBSD Foundation
With lld-generated binaries the first PT_LOAD will usually be a read-only
segment unless you pass --no-rosegment. For those binaries the textsize is
determined by the next PT_LOAD. To allow both LLD and bfd 2.17 binaries to
be parsed correctly use the end of the last PT_LOAD that is marked as
executable instead.
I noticed that the value was wrong while adding some debug prints for some rtld
changes for CHERI binaries. `obj->textsize` only seems to be used by PPC so the
effect is untested. However, the value before was definitely wrong and the new
result matches the phdrs.
Reviewed By: kib
Approved By: brooks (mentor)
Differential Revision: https://reviews.freebsd.org/D17117
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
No functional change intended.
Rtld checks and use old MAP_ANON/PROT_NONE method of creating gap if
running on old kernel.
Reviewed by: alc, markj
Tested by: pho, Qualys
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
If the mapped object is linked at specific address, we must obey it.
If AT_EXECFD is not used, only in-kernel ELF image activator needed to
keep the mapping address, since only binaries are linked at the fixed
address, and binaries are mapped by kernel in this case.
Reviewed by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
X-Differential revision: https://reviews.freebsd.org/D10701
segment. According to gABI spec, presence of the tag indicates that
dynamic linker must be prepared to handle relocations against any
read-only segment, not only the segment which we, somewhat arbitrary,
declared the text.
For each read-only segment, add write permission before relocs are
processed, and return to the mapping mode requested by the phdr, after
relocs are done.
Reported, tested, and reviewed by: emaste
PR: 207631
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
time ago, but for some reason it was not. Basically, without this change
dlopen(3)'ing an empty .so file would just cause application to dump core
with SIGSEGV.
Make sure the file has enough data for at least the ELF header before
mmap'ing it.
Add a test case to check that dlopen an empty file return an error.
There were a separate discussion as to whether it should be SIGBUS
instead when you try to access region mapped from an empty file,
but it's definitely SIGSEGV now, so if anyone want to check that please
be my guest.
Reviewed by: mjg, cem
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D5112
image.
The dynamic linker still requires that program headers of the
executable or dso are mapped by a PT_LOAD segment.
Reviewed by: emaste, jhb
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D3871
first calls mmap() with the arguments PROT_NONE and MAP_ANON to reserve a
single, contiguous range of virtual addresses for the entire shared library.
Later, rtld calls mmap() with the the shared library's file descriptor
and the argument MAP_FIXED to place the text and data sections within the
reserved range. The rationale for mapping shared libraries in this way is
explained in the commit message for Revision 190885. However, this approach
does have an unintended, negative consequence. Since the first call to
mmap() specifies MAP_ANON and not the shared library's file descriptor, the
kernel has no idea what alignment the vm object backing the file prefers.
As a result, the reserved range's alignment is unlikely to be the same as
the vm object's, and so mapping with superpages becomes impossible. To
address this problem, this revision adds the argument MAP_ALIGNED_SUPER to
the first call to mmap() if the text section is larger than the smallest
superpage size.
To determine if the text section is larger than the smallest superpage
size, rtld must always fetch the page size information. As a result, the
private code for fetching the base page size in rtld's builtin malloc is
redundant. Eliminate it. Requested by: kib
Tested by: zbb (on arm)
Reviewed by: kib (an earlier version)
Discussed with: jhb
Normal libraries have base address 0 and are unaffected by this change.
PR: 176216
Submitted by: Damjan Jovanovic <damjan.jov@gmail.com>
Reviewed by: kib
MFC after: 1 week
object, and eliminate the pread(2) call as well [1]. Mmap the first
page of the object temporaly, and unmap it on error or last use.
Potentially, this leaves one-page gap between succeeding dlopen(3),
but there are other mmap(2) consumers as well.
Fix several cases were the whole mapping of the object leaked on error.
Use MAP_PREFAULT_READ for mmap(2) calls which map real object pages [2].
Insipired by the patch by: Ian Lepore <freebsd damnhippie dyndns org> [1]
Suggested by: alc [2]
MFC after: 2 weeks
Stop using strerror(3) in rtld, which brings in msgcat and stdio.
Directly access sys_errlist array of errno messages with private
rtld_strerror() function.
Now,
$ size /libexec/ld-elf.so.1
text data bss dec hex filename
96983 2480 8744 108207 1a6af /libexec/ld-elf.so.1
Reviewed by: dim, kan
MFC after: 2 weeks
yet, and object segments are not yet mapped. Only parse the notes that
appear in the first page of the dso (as it should be anyway), and use
the preloaded page content.
Reported and tested by: stass
MFC after: 20 days
particular on ARM, do require working init arrays.
Traditional FreeBSD crt1 calls _init and _fini of the binary, instead
of allowing runtime linker to arrange the calls. This was probably
done to have the same crt code serve both statically and dynamically
linked binaries. Since ABI mandates that first is called preinit
array functions, then init, and then init array functions, the init
have to be called from rtld now.
To provide binary compatibility to old FreeBSD crt1, which calls _init
itself, rtld only calls intializers and finalizers for main binary if
binary has a note indicating that new crt was used for linking. Add
parsing of ELF notes to rtld, and cache p_osrel value since we parsed
it anyway.
The patch is inspired by init_array support for DragonflyBSD, written
by John Marino.
Reviewed by: kan
Tested by: andrew (arm, previous version), flo (sparc64, previous version)
MFC after: 3 weeks
executable) after r190885. The whole region for the dso is mmaped with
MAP_NOCORE flag, doing only mprotect(2) over .bss prevented it from
writing .bss to core files.
Revert the optimization of using mprotect(2) to establish .bss, overlap
the section with mmap(2).
Reported by: attilio
Reviewed by: attilio, emaste
Approved by: re (bz)
MFC after: 2 weeks
by kernel, and parse PT_GNU_STACK phdr from linked and loaded dsos.
If the loaded dso requires executable stack, as specified by PF_X bit
of p_flags of PT_GNU_STACK phdr, but current stack protection does not
permit execution, the __pthread_map_stacks_exec symbol is looked up
and called. It should be implemented in libc or threading library and
change the protection mode of all thread stacks to be executable.
Provide a private interface _rtld_get_stack_prot() to export the stack
access mode as calculated by rtld.
Reviewed by: kan
ELF header from the front of the file. As all other I/O on the binary
is done using mmap(), this avoids the need for seek privileges on the
file descriptor during run-time linking.
MFC after: 1 month
Sponsored by: Google
is not equal to its memory size.
This eliminates unneeded clearing of the text segment that often
happens due to text end not being page-aligned.
For instance,
$ readelf -l /lib/libedit.so.6
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000000 0x00000000 0x00000000 0x139e1 0x139e1 R E 0x1000
LOAD 0x014000 0x00014000 0x00014000 0x00f04 0x00f14 RW 0x1000
DYNAMIC 0x014cc4 0x00014cc4 0x00014cc4 0x000d0 0x000d0 RW 0x4
$ procstat -v $$ (for /bin/sh)
68585 0x28097000 0x280aa000 r-x 6 0 21 14 CN vn /lib/libedit.so.6
68585 0x280aa000 0x280ab000 r-x 1 0 1 0 CN vn /lib/libedit.so.6 <==
68585 0x280ab000 0x280ac000 rwx 1 0 1 0 CN vn /lib/libedit.so.6
Note the splitted map entry marked by '<=='.
Reviewed by: kan
Approved by: re (kensmith)
MFC after: 1 month
for the mapping by the object' file with the protection and mode of
the first loadable segment over the whole region. Then, it maps other
segments at the appropriate addresses inside the region.
On amd64, due to default alignment of the segments being 1Gb, the
subsequent segment mappings leave the holes in the region, that usually
contain mapping of the object' file past eof. Such mappings prevent
wiring of the address space, because the pages cannot be faulted in.
Change the way the mapping of the ELF objects is constructed, by first
mapping PROT_NONE anonymous memory over the whole range, and then
mapping the segments of the object over it. Take advantage of this new
order and allocate .bss by changing the protection of the range instead
of remapping.
Note that we cannot simply keep the holes between segments, because
other mappings may be made there. Among other issues, when the dso is
unloaded, rtld unmaps the whole region, deleting unrelated mappings.
The kernel ELF image activator does put the holes between segments, but
this is not critical for now because kernel loads only executable image
and interpreter, both cannot be unloaded. This will be fixed later, if
needed.
Reported and tested by: Hans Ottevanger <fbsdhackers beasties demon nl>
Suggested and reviewed by: kan, alc
soneeded pathes. The $ORIGIN, $OSNAME, $OSREL and $PLATFORM tokens
are supported. Enabling the substitution requires DF_ORIGIN flag in
DT_FLAGS or DF_1_ORIGIN if DF_FLAGS_1, that may be set with -z origin
gnu ld flag. Translation is unconditionally disabled for setuid/setgid
processes.
The $ORIGIN translation relies on the AT_EXECPATH auxinfo supplied
by kernel.
Requested by: maho
Tested by: maho, pho
Reviewed by: kan
to be compatible with symbol versioning support as implemented by
GNU libc and documented by http://people.redhat.com/~drepper/symbol-versioning
and LSB 3.0.
Implement dlvsym() function to allow lookups for a specific version of
a given symbol.
skipping read-only pages, which can result in valuable non-text-related
data not getting dumped, the ELF loader and the dynamic loader now mark
read-only text pages NOCORE and the coredump code only checks (primarily) for
complete inaccessibility of the page or NOCORE being set.
Certain applications which map large amounts of read-only data will
produce much larger cores. A new sysctl has been added,
debug.elf_legacy_coredump, which will revert to the old behavior.
This commit represents collaborative work by all parties involved.
The PR contains a program demonstrating the problem.
PR: kern/45994
Submitted by: "Peter Edwards" <pmedwards@eircom.net>, Archie Cobbs <archie@dellroad.org>
Reviewed by: jdp, dillon
MFC after: 7 days
