elf: Fix runtime linker auditing on aarch64 (BZ #26643)

The rtld audit support show two problems on aarch64:

  1. _dl_runtime_resolve does not preserve x8, the indirect result
      location register, which might generate wrong result calls
      depending of the function signature.

  2. The NEON Q registers pushed onto the stack by _dl_runtime_resolve
     were twice the size of D registers extracted from the stack frame by
     _dl_runtime_profile.

While 2. might result in wrong information passed on the PLT tracing,
1. generates wrong runtime behaviour.

The aarch64 rtld audit support is changed to:

  * Both La_aarch64_regs and La_aarch64_retval are expanded to include
    both x8 and the full sized NEON V registers, as defined by the
    ABI.

  * dl_runtime_profile needed to extract registers saved by
    _dl_runtime_resolve and put them into the new correctly sized
    La_aarch64_regs structure.

  * The LAV_CURRENT check is change to only accept new audit modules
    to avoid the undefined behavior of not save/restore x8.

  * Different than other architectures, audit modules older than
    LAV_CURRENT are rejected (both La_aarch64_regs and La_aarch64_retval
    changed their layout and there are no requirements to support multiple
    audit interface with the inherent aarch64 issues).

  * A new field is also reserved on both La_aarch64_regs and
    La_aarch64_retval to support variant pcs symbols.

Similar to x86, a new La_aarch64_vector type to represent the NEON
register is added on the La_aarch64_regs (so each type can be accessed
directly).

Since LAV_CURRENT was already bumped to support bind-now, there is
no need to increase it again.

Checked on aarch64-linux-gnu.

Co-authored-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/sysdeps/aarch64/tst-audit27mod.c b/sysdeps/aarch64/tst-audit27mod.c
new file mode 100644
index 0000000..922b518
--- /dev/null
+++ b/sysdeps/aarch64/tst-audit27mod.c
@@ -0,0 +1,95 @@
+/* Check LD_AUDIT for aarch64 ABI specifics.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <array_length.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include "tst-audit27mod.h"
+
+float
+tst_audit27_func_float (float a0, float a1, float a2, float a3, float a4,
+			float a5, float a6, float a7)
+{
+  if (a0 != FUNC_FLOAT_ARG0)
+    FAIL_EXIT1 ("a0: %a != %a", a0, FUNC_FLOAT_ARG0);
+  if (a1 != FUNC_FLOAT_ARG1)
+    FAIL_EXIT1 ("a1: %a != %a", a1, FUNC_FLOAT_ARG1);
+  if (a2 != FUNC_FLOAT_ARG2)
+    FAIL_EXIT1 ("a2: %a != %a", a2, FUNC_FLOAT_ARG2);
+  if (a3 != FUNC_FLOAT_ARG3)
+    FAIL_EXIT1 ("a3: %a != %a", a3, FUNC_FLOAT_ARG3);
+  if (a4 != FUNC_FLOAT_ARG4)
+    FAIL_EXIT1 ("a4: %a != %a", a4, FUNC_FLOAT_ARG4);
+  if (a5 != FUNC_FLOAT_ARG5)
+    FAIL_EXIT1 ("a5: %a != %a", a5, FUNC_FLOAT_ARG5);
+  if (a6 != FUNC_FLOAT_ARG6)
+    FAIL_EXIT1 ("a6: %a != %a", a6, FUNC_FLOAT_ARG6);
+  if (a7 != FUNC_FLOAT_ARG7)
+    FAIL_EXIT1 ("a7: %a != %a", a7, FUNC_FLOAT_ARG7);
+
+  return FUNC_FLOAT_RET;
+}
+
+double
+tst_audit27_func_double (double a0, double a1, double a2, double a3, double a4,
+			 double a5, double a6, double a7)
+{
+  if (a0 != FUNC_DOUBLE_ARG0)
+    FAIL_EXIT1 ("a0: %la != %la", a0, FUNC_DOUBLE_ARG0);
+  if (a1 != FUNC_DOUBLE_ARG1)
+    FAIL_EXIT1 ("a1: %la != %la", a1, FUNC_DOUBLE_ARG1);
+  if (a2 != FUNC_DOUBLE_ARG2)
+    FAIL_EXIT1 ("a2: %la != %la", a2, FUNC_DOUBLE_ARG2);
+  if (a3 != FUNC_DOUBLE_ARG3)
+    FAIL_EXIT1 ("a3: %la != %la", a3, FUNC_DOUBLE_ARG3);
+  if (a4 != FUNC_DOUBLE_ARG4)
+    FAIL_EXIT1 ("a4: %la != %la", a4, FUNC_DOUBLE_ARG4);
+  if (a5 != FUNC_DOUBLE_ARG5)
+    FAIL_EXIT1 ("a5: %la != %la", a5, FUNC_DOUBLE_ARG5);
+  if (a6 != FUNC_DOUBLE_ARG6)
+    FAIL_EXIT1 ("a6: %la != %la", a6, FUNC_DOUBLE_ARG6);
+  if (a7 != FUNC_DOUBLE_ARG7)
+    FAIL_EXIT1 ("a7: %la != %la", a7, FUNC_DOUBLE_ARG7);
+
+  return FUNC_DOUBLE_RET;
+}
+
+long double
+tst_audit27_func_ldouble (long double a0, long double a1, long double a2,
+			  long double a3, long double a4, long double a5,
+			  long double a6, long double a7)
+{
+  if (a0 != FUNC_LDOUBLE_ARG0)
+    FAIL_EXIT1 ("a0: %La != %La", a0, FUNC_LDOUBLE_ARG0);
+  if (a1 != FUNC_LDOUBLE_ARG1)
+    FAIL_EXIT1 ("a1: %La != %La", a1, FUNC_LDOUBLE_ARG1);
+  if (a2 != FUNC_LDOUBLE_ARG2)
+    FAIL_EXIT1 ("a2: %La != %La", a2, FUNC_LDOUBLE_ARG2);
+  if (a3 != FUNC_LDOUBLE_ARG3)
+    FAIL_EXIT1 ("a3: %La != %La", a3, FUNC_LDOUBLE_ARG3);
+  if (a4 != FUNC_LDOUBLE_ARG4)
+    FAIL_EXIT1 ("a4: %La != %La", a4, FUNC_LDOUBLE_ARG4);
+  if (a5 != FUNC_LDOUBLE_ARG5)
+    FAIL_EXIT1 ("a5: %La != %La", a5, FUNC_LDOUBLE_ARG5);
+  if (a6 != FUNC_LDOUBLE_ARG6)
+    FAIL_EXIT1 ("a6: %La != %La", a6, FUNC_LDOUBLE_ARG6);
+  if (a7 != FUNC_LDOUBLE_ARG7)
+    FAIL_EXIT1 ("a7: %La != %La", a7, FUNC_LDOUBLE_ARG7);
+
+  return FUNC_LDOUBLE_RET;
+}