Use the standard syntax of name@version, I do not expect a confusion
due to unlikely possibility of the name containing the '@' character.
Requested by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
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
Reviewed by: emaste, jonathan (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D10826
Fix warnings about redundant declarations in rtld
when libthr in increased to WARNS=6.
Reviewed by: kib
MFC after: 3 days
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D10934
When I originally documented the LD_LIBRARY_PATH_FDS environment variable,
I used `.Ev` rather than `.It Ev` to introduce it; this led to the
documentation being embedded in the previous paragraph (LD_LIBRARY_PATH).
When executing rtld directly, allow a file descriptor to be explicitly
specified rather than opened from the given path. This, together with the
LD_LIBRARY_PATH_FDS environment variable, allows dynamically-linked
applications to be executed from within capability mode.
Also add some rudimentary argument parsing (without pulling in getopt or
the like) to accept this file descriptor, a help (-h) option and a basic
usage string.
Reviewed by: kib
Sponsored by: NSERC, RDC
Differential Revision: https://reviews.freebsd.org/D10751
Do not allow direct exec if we the process is suid. Try to follow Unix
permission checks for DACs, ignore ACLs.
Reviewed by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D10750
This is a more accurate name, as the integer doesn't have to be a library
directory descriptor. It is also a prerequisite for more argument parsing
coming in the near future (e.g., parsing explicit binary descriptors).
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: NSERC
Check if passed phdr is actually phdr of the interpreter itself, and
decide that this is the case of direct execution. In this case, the
binary to activate is specified in the argv[1]. After opening it,
shift down on-stack structure with argv, env and aux vectors to
emulate execution of the binary and not of the interpreter.
Reviewed by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D10701
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
partially sort them by style(9). Move locals declarations from nested
blocks into the block at function start.
Discussed with: emaste
MFC after: 1 week
From the manpage:
When set to a nonempty string, prevents modifications of the PLT slots
when doing bindings. As result, each call of the PLT-resolved
function is resolved. In combination with debug output, this provides
complete account of all bind actions at runtime.
Same feature exists on Linux and Solaris.
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
When dlclose(3) unloads an object with filtees, it recursively calls
dlclose(3) on each filtee in free_needed_filtees(). Introduce
dlclose_locked() helper, called from free_needed_filtees() instead of
dlclose(), and pass the bind lockstate down to avoid recursing.
Reported and tested by: jhibbits
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
The MIPS ABI does not require the second GOT entry to be reserved for use
by the runtime linker as on other architectures. Instead, static linkers
use a special value in the second GOT entry to indicate if the entry is
reserved. This value is supposed to consist of an address with the MSB
set and the rest of the bits all zero which is an invalid user address.
However, the old binutils currently in the tree uses the 32-bit mask value
(2^31) on 64-bit MIPS instead of 2^63. This was fixed in upstream
binutils in 2008 to use 2^63 on 64-bit MIPS.
The first part of this change changes the runtime check in init_pltgot()
to check for both values (2^31 and 2^63) when deciding whether to store
the current object pointer in GOT[1] which fixes dynamic N64 binaries
compiled with modern binutils.
However, the initial version of this fix exposed another related bug in
that _rtld_relocate_nonplt_self() was only checking for the new value
(2^63) in GOT[1] and incorrectly treated GOT[1] as a local GOT entry
(and did not relocate the final local GOT entry). To handle this, fix
all of the places that check for GOT[1]'s status to use the same macro
that checks for both values on N64.
Reviewed by: kan, imp
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D9708
Protected symbol reference in GOT of the defining object must be
resolved to itself, same as -Bsymbolic globally.
Discussed with: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D9317
The duplicate call to store_ptr() was added in r204687, but it should
have no effect as it only stores an Elf_Sword and the later store_ptr()
does a write that is at least as large if not larger.
Reviewed by: jmallett
Obtained from: CheriBSD (sort of)
Sponsored by: DARPA / AFRL
both the plt and non-plt case.
This fixes an issue where libraries built with LLD can fail with
"Unhandled relocation 1031"
PR: 214971
Obtained from: 1 week
Sponsored by: DARPA, AFRL
On rela architectures GNU BFD ld and gold store the relocation addend
in GOT entries (in addition to the relocation's r_addend field).
rtld previously relied on this to access its own _DYNAMIC symbol in
order to apply its own relocations.
However, recording addends in the GOT is not specified by the ABI,
and some versions of LLVM's LLD linker leave the GOT uninitialized on
rela architectures.
BFD ld does not populate the GOT on sparc64, and sparc64 rtld has a
machine-dependent rtld_dynamic_addr() function that returns the
_DYNAMIC address. Use the same approach on amd64, obtaining the %rip-
relative _DYNAMIC address following a suggestion from Rafael Espíndola.
Architectures other than amd64 should be addressed in future work.
PR: 214972
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D9180
until copy relocations are done.
Newer binutils and lld seems to output copy into relro-protected range.
Reported by: Rafael Espц╜ndola via emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Obtaining compat rtld lock in write mode sets process signal mask to
block all signals. Previous mask is stored in the global variable
oldsigmask. If a lock is write-locked while another lock is already
write-locked, oldsigmask is overwritten by the total mask and on the
last unlock, all signals except traps appear to be blocked.
Fix this by counting the write-lock nested level, and only storing to
oldsigmask/restoring from it at the outermost level.
Masking signals disables involuntary preemption for libc_r, and there
could be no voluntary context switches in the locked code
(dl_iterate_phdr(3) keeps a lock around user callback, but it was
added long after libc_r was renounced). Due to this, remembering the
level in the global variable after the lock is obtained should be
safe, because no two libc_r threads can acquire different write locks
in parallel.
PR: 215826
Reported by: kami
Tested by: yamagi@yamagi.org (previous version)
To be reviewed by: kan
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
- Pass the correct object to unload_filtees().
- Use a marker to restart iteration after unload_filtees() has returned.
It calls dlclose() and may recursively remove entries from the global
object list, so TAILQ_FOREACH_SAFE is not sufficient.
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
rtld drops the bind lock to call fini functions in an object prior to
unmapping it. The new "doomed" state flag prevents the acquisition of new
references for an object while the lock is dropped.
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Add a transient reference count to ensure that the phdr argument to the
callback remains valid while the bind lock is dropped.
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
This avoids a race with readers such as dladdr(3)/dlinfo(3)/dlsym(3) and
the atexit(3) handler. This race was introduced in r294373.
Reviewed by: markj, kib, kan
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
rtld-elf has some vestigial support for building as a static executable.
r45501 introduced a partial implementation with a prescient note that it
"might never be enabled." r153515 introduced ELF symbol versioning
support, and removed part of the unused build infrastructure for static
rtld.
GNU ld populates rela relocation addends and GOT entries with the same
values, and rtld's run-time dynamic executable check relied on this.
Alternate toolchains may not populate the GOT entries, which caused
RTLD_IS_DYNAMIC to return false. Simplify rtld by just removing the
unused check.
If we want to restore static rtld support later on we ought to introduce
a build-time #ifdef flag.
PR: 214972
Reviewed by: kan
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D8687
MIPS does not use the common _rtld_bind() to handle runtime binding.
Instead, it uses a private _mips_rtld_bind(). Update _mips_rtld_bind()
to include the changes made to _rtld_bind() in r216695 and r218476 to
support upgrading the read-locked rtld_bind_lock to a write lock when
an object with a filter is encountered.
While here, add a 'where' variable to track the location of the fixup
in the GOT to make the code flow more closely match _rtld_bind().
Reviewed by: kib
Obtained from: CheriBSD
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D8625
(hopefully) stock gcc 4.2.1 on i386 and other arches.
In particular:
- Do not use %ebx in the asm constraints on i386, since rtld is
compiled with -fPIC and gcc cannot handle GOT-base register reload
(clang and newer gcc can).
- Avoid direct use of [static N] construct in the function
declaration/definion. In-tree gcc was patched to support this, but
stock 4.2.1 cannot handle the feature.
Requested by: bde
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
CPUID[7].%ebx (cpu_stdext_feature), %ecx (cpu_stdext_feature2) to the
ifunc resolvers on x86.
It is much more clean to use CPUID instruction in usermode to retrieve
this information than to pass AT_HWCAP aux vector from kernel, on
x86. Still, the change does allow for use of AT_HWCAP on arches where it is
needed, by passing aux array to ifunc_init() initializer which should
prepare arguments for ifunc resolvers.
Current signature for resolvers on x86 is
func_t iresolve(uint32_t cpu_feature, uint32_t cpu_feature2,
uint32_t cpu_stdext_feature, uint32_t cpu_stdext_feature2);
where arguments have identical meaning as the kernel variables of the
same name. The ABIs allow to use resolvers with the void or shortened
list of arguments.
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D8448
When symbol versioning was added to rtld, the boolean 'in_plt' argument
to find_symdef() was converted to a bitmask of flags. The first flag
added was 'SYMLOOK_IN_PLT' which replaced the 'in_plt' bool. This
happened to still work by accident as SYMLOOK_IN_PLT had the value of 1
which is the same as 'true', so there should be no functional change.
Tested on: amd64
Reviewed by: kan
MFC after: 2 weeks
Sponsored by: DARPA / AFRL
=v is some ye olde gcc "use this specific register as the temp register"
thing that they've deprecated and clang/llvm doesn't implement.
Poked again and again by: sbruno
