glibc/elf/rtld.c, branch vdso

rtld: Fix handling of '--' option

2024-08-06T13:26:17Z

It always resulted in the error `unrecognized option '--'` previously. Reviewed-by: Adhemerval Zanella

elf: Clarify and invert second argument of _dl_allocate_tls_init

2024-08-05T16:26:42Z

Also remove an outdated comment: _dl_allocate_tls_init is called as part of pthread_create. Reviewed-by: Carlos O'Donell

elf/rtld: Fix auxiliary vector for enable_secure

2024-07-03T11:01:44Z

Starting with commit 59974938fe1f4add843f5325f78e2a7ccd8db853 elf/rtld: Count skipped environment variables for enable_secure The new testcase elf/tst-tunables-enable_secure-env segfaults on s390 (31bit). There _start parses the auxiliary vector for some additional checks. Therefore it skips over the zeros after the environment variables ... 0x7fffac20: 0x7fffbd17 0x7fffbd32 0x7fffbd69 0x00000000 ------------------------------------------------^^^last environment variable ... and then it parses the auxiliary vector and stops at AT_NULL. 0x7fffac30: 0x00000000 0x00000021 0x00000000 0x00000000 --------------------------------^^^AT_SYSINFO_EHDR--------------^^^AT_NULL ----------------^^^newp-----------------------------------------^^^oldp Afterwards it tries to access AT_PHDR which points to somewhere and segfaults. Due to not incorporating the skip_env variable in the computation of oldp when shuffling down the auxv in rtld.c, it just copies one entry with AT_NULL and value 0x00000021 and stops the loop. In reality we have skipped GLIBC_TUNABLES environment variable (=> skip_env=1). Thus we should copy from here: 0x7fffac40: 0x00000021 0x7ffff000 0x00000010 0x007fffff ----------------^^^fixed-oldp This patch fixes the computation of oldp when shuffling down auxiliary vector. It also adds some checks in the testcase. Those checks also fail on s390x (64bit) and x86_64 without the fix. Co-authored-by: Adhemerval Zanella Reviewed-by: Adhemerval Zanella

elf: Support recursive use of dynamic TLS in interposed malloc

2024-07-01T17:02:11Z

It turns out that quite a few applications use bundled mallocs that have been built to use global-dynamic TLS (instead of the recommended initial-exec TLS). The previous workaround from commit afe42e935b3ee97bac9a7064157587777259c60e ("elf: Avoid some free (NULL) calls in _dl_update_slotinfo") does not fix all encountered cases unfortunatelly. This change avoids the TLS generation update for recursive use of TLS from a malloc that was called during a TLS update. This is possible because an interposed malloc has a fixed module ID and TLS slot. (It cannot be unloaded.) If an initially-loaded module ID is encountered in __tls_get_addr and the dynamic linker is already in the middle of a TLS update, use the outdated DTV, thus avoiding another call into malloc. It's still necessary to update the DTV to the most recent generation, to get out of the slow path, which is why the check for recursion is needed. The bookkeeping is done using a global counter instead of per-thread flag because TLS access in the dynamic linker is tricky. All this will go away once the dynamic linker stops using malloc for TLS, likely as part of a change that pre-allocates all TLS during pthread_create/dlopen. Fixes commit d2123d68275acc0f061e73d5f86ca504e0d5a344 ("elf: Fix slow tls access after dlopen [BZ #19924]"). Reviewed-by: Szabolcs Nagy

Revert "Allow glibc to be compiled without EXEC_PAGESIZE"

2024-04-22T21:00:18Z

This reverts commit 49aa652db810ebdca3a662ebd5b0468bd08ec688. This is still being discussed.

elf/rtld: Count skipped environment variables for enable_secure

2024-04-16T20:32:10Z

When using the glibc.rtld.enable_secure tunable we need to keep track of the count of environment variables we skip due to __libc_enable_secure being set and adjust the auxv section of the stack. This fixes an assertion when running ld.so directly with glibc.rtld.enable_secure set. Add a testcase that ensures the assert is not hit. elf/rtld.c:1324 assert (auxv == sp + 1); Reviewed-by: Adhemerval Zanella

Allow glibc to be compiled without EXEC_PAGESIZE

2024-03-23T21:47:26Z

We would like to avoid statically defining any specific page size on aarch64-gnu, and instead make sure that everything uses the dynamic page size, available via vm_page_size and GLRO(dl_pagesize). There are currently a few places in glibc that require EXEC_PAGESIZE to be defined. Per Roland's suggestion [0], drop the static GLRO(dl_pagesize) initializers (for now, only if EXEC_PAGESIZE is not defined), and don't require EXEC_PAGESIZE definition for libio to enable mmap usage. [0]: https://mail.gnu.org/archive/html/bug-hurd/2011-10/msg00035.html Signed-off-by: Sergey Bugaev Message-ID: <20240323173301.151066-4-bugaevc@gmail.com>

elf: correct relocation statistics for !ELF_MACHINE_START_ADDRESS

2024-01-29T17:27:35Z

Fixes: 6628c742b2 ("elf: Remove prelink support")

Update copyright dates with scripts/update-copyrights

2024-01-01T18:53:40Z

elf: Initialize GLRO(dl_lazy) before relocating libc in dynamic startup

2023-12-08T13:33:03Z

GLRO(dl_lazy) is used to set the parameters for the early _dl_relocate_object call, so the consider_profiling setting has to be applied before the call. Fixes commit 78ca44da0160a0b442f0ca1f253e3360f044b2ec ("elf: Relocate libc.so early during startup and dlmopen (bug 31083)"). Reviewed-by: Carlos O'Donell