glibc:fw/bug24214

Last commit made on 2019-11-29
Get this branch:
git clone -b fw/bug24214 https://git.launchpad.net/glibc

Branch merges

Branch information

Name:
fw/bug24214
Repository:
lp:glibc

Recent commits

6029860... by Florian Weimer on 2019-11-29

elf: Do not run IFUNC resolvers for LD_DEBUG=unused [BZ #24214]

This commit adds missing skip_ifunc checks to aarch64, arm, i386,
sparc, and x86_64. A new test case ensures that IRELATIVE IFUNC
resolvers do not run in various diagnostic modes of the dynamic
loader.

Tested on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
s390-linux-gnu, s390x-linux-gnu, powerpc64le-linux-gnu. Built with
build-many-glibcs.py.

a331150... by Joseph Myers <email address hidden> on 2019-11-28

Update syscall-names.list for Linux 5.4.

This patch updates syscall-names.list for Linux 5.4. There are no new
syscalls, so this is just a matter of updating the version number
listed in the file.

Tested with build-many-glibcs.py.

cdf2036... by Joseph Myers <email address hidden> on 2019-11-28

Fix syntax error in build-many-glibcs.py.

The recent SPARC changes caused a syntax error:

    'ccopts': '-m32 -mlong-double-128 -mcpu=v9'}],
                                                ^
SyntaxError: invalid syntax

Fixed by this patch.

aa9452a... by Joseph Myers <email address hidden> on 2019-11-28

Define MADV_COLD and MADV_PAGEOUT from Linux 5.4.

Linux 5.4 adds constants MADV_COLD and MADV_PAGEOUT (defined with the
same values on all architectures). This patch adds them to
bits/mman-linux.h.

Tested for x86_64.

e37c2cf... by Florian Weimer on 2019-10-31

Move _dl_open_check to its original place in dl_open_worker

This reverts the non-test change from commit d0093c5cefb7f7a4143f
("Call _dl_open_check after relocation [BZ #24259]"), given that
the underlying bug has been fixed properly in commit 61b74477fa7f63
("Remove all loaded objects if dlopen fails, ignoring NODELETE
[BZ #20839]").

Tested on x86-64-linux-gnu, with and without --enable-cet.

Change-Id: I995a6cfb89f25d2b0cf5e606428c2a93eb48fc33

a2e8aa0... by Florian Weimer on 2019-10-31

Block signals during the initial part of dlopen

Lazy binding in a signal handler that interrupts a dlopen sees
intermediate dynamic linker state. This has likely been always
unsafe, but with the new pending NODELETE state, this is clearly
incorrect. Other threads are excluded via the loader lock, but the
current thread is not. Blocking signals until right before ELF
constructors run is the safe thing to do.

Change-Id: Iad079080ebe7442c13313ba11dc2797953faef35

f63b738... by Florian Weimer on 2019-11-13

Remove all loaded objects if dlopen fails, ignoring NODELETE [BZ #20839]

This introduces a “pending NODELETE” state in the link map, which is
flipped to the persistent NODELETE state late in dlopen, via
activate_nodelete. During initial relocation, symbol binding
records pending NODELETE state only. dlclose ignores pending NODELETE
state. Taken together, this results that a partially completed dlopen
is rolled back completely because new NODELETE mappings are unloaded.

Tested on x86_64-linux-gnu and i386-linux-gnu.

Change-Id: Ib2a3d86af6f92d75baca65431d74783ee0dbc292

a509eb1... by Florian Weimer on 2019-11-27

Avoid late dlopen failure due to scope, TLS slotinfo updates [BZ #25112]

This change splits the scope and TLS slotinfo updates in dlopen into
two parts: one to resize the data structures, and one to actually apply
the update. The call to add_to_global_resize in dl_open_worker is moved
before the demarcation point at which no further memory allocations are
allowed.

_dl_add_to_slotinfo is adjusted to make the list update optional. There
is some optimization possibility here because we could grow the slotinfo
list of arrays in a single call, one the largest TLS modid is known.

This commit does not fix the fatal meory allocation failure in
_dl_update_slotinfo. Ideally, this error during dlopen should be
recoverable.

The update order of scopes and TLS data structures is retained, although
it appears to be more correct to fully initialize TLS first, and then
expose symbols in the newly loaded objects via the scope update.

Tested on x86_64-linux-gnu.

Change-Id: I240c58387dabda3ca1bcab48b02115175fa83d6c

440b7f8... by Florian Weimer on 2019-10-31

Avoid late failure in dlopen in global scope update [BZ #25112]

The call to add_to_global in dl_open_worker happens after running ELF
constructors for new objects. At this point, proper recovery from
malloc failure would be quite complicated: We would have to run the
ELF destructors and close all opened objects, something that we
currently do not do.

Instead, this change splits add_to_global into two phases,
add_to_global_resize (which can raise an exception, called before ELF
constructors run), and add_to_global_update (which cannot, called
after ELF constructors). A complication arises due to recursive
dlopen: After the inner dlopen consumes some space, the pre-allocation
in the outer dlopen may no longer be sufficient. A new member in the
namespace structure, _ns_global_scope_pending_adds keeps track of the
maximum number of objects that need to be added to the global scope.
This enables the inner add_to_global_resize call to take into account
the needs of an outer dlopen.

Most code in the dynamic linker assumes that the number of global
scope entries fits into an unsigned int (matching the r_nlist member
of struct r_scop_elem). Therefore, change the type of
_ns_global_scope_alloc to unsigned int (from size_t), and add overflow
checks.

Change-Id: Ie08e2f318510d5a6a4bcb1c315f46791b5b77524

79e0cd7... by Florian Weimer on 2019-11-27

Lazy binding failures during dlopen/dlclose must be fatal [BZ #24304]

If a lazy binding failure happens during the execution of an ELF
constructor or destructor, the dynamic loader catches the error
and reports it using the dlerror mechanism. This is undesirable
because there could be other constructors and destructors that
need processing (which are skipped), and the process is in an
inconsistent state at this point. Therefore, we have to issue
a fatal dynamic loader error error and terminate the process.

Note that the _dl_catch_exception in _dl_open is just an inner catch,
to roll back some state locally. If called from dlopen, there is
still an outer catch, which is why calling _dl_init via call_dl_init
and a no-exception is required and cannot be avoiding by moving the
_dl_init call directly into _dl_open.

_dl_fini does not need changes because it does not install an error
handler, so errors are already fatal there.

Change-Id: I6b1addfe2e30f50a1781595f046f44173db9491a