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glibc/SOURCES/glibc-upstream-2.34-252.patch

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commit ede8d94d154157d269b18f3601440ac576c1f96a
Author: Florian Weimer <fweimer@redhat.com>
Date: Mon May 16 18:41:43 2022 +0200
csu: Implement and use _dl_early_allocate during static startup
This implements mmap fallback for a brk failure during TLS
allocation.
scripts/tls-elf-edit.py is updated to support the new patching method.
The script no longer requires that in the input object is of ET_DYN
type.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit f787e138aa0bf677bf74fa2a08595c446292f3d7)
Conflicts:
elf/Makefile
(missing ld.so static execve backport upstream)
sysdeps/generic/ldsodefs.h
(missing ld.so dependency sorting optimization upstream)
diff --git a/csu/libc-tls.c b/csu/libc-tls.c
index d83e69f6257ae981..738f59f46b62c31c 100644
--- a/csu/libc-tls.c
+++ b/csu/libc-tls.c
@@ -145,11 +145,16 @@ __libc_setup_tls (void)
_dl_allocate_tls_storage (in elf/dl-tls.c) does using __libc_memalign
and dl_tls_static_align. */
tcb_offset = roundup (memsz + GLRO(dl_tls_static_surplus), max_align);
- tlsblock = __sbrk (tcb_offset + TLS_INIT_TCB_SIZE + max_align);
+ tlsblock = _dl_early_allocate (tcb_offset + TLS_INIT_TCB_SIZE + max_align);
+ if (tlsblock == NULL)
+ _startup_fatal ("Fatal glibc error: Cannot allocate TLS block\n");
#elif TLS_DTV_AT_TP
tcb_offset = roundup (TLS_INIT_TCB_SIZE, align ?: 1);
- tlsblock = __sbrk (tcb_offset + memsz + max_align
- + TLS_PRE_TCB_SIZE + GLRO(dl_tls_static_surplus));
+ tlsblock = _dl_early_allocate (tcb_offset + memsz + max_align
+ + TLS_PRE_TCB_SIZE
+ + GLRO(dl_tls_static_surplus));
+ if (tlsblock == NULL)
+ _startup_fatal ("Fatal glibc error: Cannot allocate TLS block\n");
tlsblock += TLS_PRE_TCB_SIZE;
#else
/* In case a model with a different layout for the TCB and DTV
diff --git a/elf/Makefile b/elf/Makefile
index 6423ebbdd7708a14..ea1512549be3f628 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -33,6 +33,7 @@ routines = \
$(all-dl-routines) \
dl-addr \
dl-addr-obj \
+ dl-early_allocate \
dl-error \
dl-iteratephdr \
dl-libc \
@@ -104,6 +105,7 @@ all-dl-routines = $(dl-routines) $(sysdep-dl-routines)
# But they are absent from the shared libc, because that code is in ld.so.
elide-routines.os = \
$(all-dl-routines) \
+ dl-early_allocate \
dl-exception \
dl-origin \
dl-reloc-static-pie \
@@ -264,6 +266,7 @@ tests-static-normal := \
tst-linkall-static \
tst-single_threaded-pthread-static \
tst-single_threaded-static \
+ tst-tls-allocation-failure-static \
tst-tlsalign-extern-static \
tst-tlsalign-static \
# tests-static-normal
@@ -1101,6 +1104,10 @@ $(objpfx)tst-glibcelf.out: tst-glibcelf.py elf.h $(..)/scripts/glibcelf.py \
--cc="$(CC) $(patsubst -DMODULE_NAME=%,-DMODULE_NAME=testsuite,$(CPPFLAGS))" \
< /dev/null > $@ 2>&1; $(evaluate-test)
+ifeq ($(run-built-tests),yes)
+tests-special += $(objpfx)tst-tls-allocation-failure-static-patched.out
+endif
+
# The test requires shared _and_ PIE because the executable
# unit test driver must be able to link with the shared object
# that is going to eventually go into an installed DSO.
@@ -2637,3 +2644,15 @@ $(objpfx)tst-ro-dynamic-mod.so: $(objpfx)tst-ro-dynamic-mod.os \
$(objpfx)tst-ro-dynamic-mod.os
$(objpfx)tst-rtld-run-static.out: $(objpfx)/ldconfig
+
+$(objpfx)tst-tls-allocation-failure-static-patched: \
+ $(objpfx)tst-tls-allocation-failure-static $(..)scripts/tst-elf-edit.py
+ cp $< $@
+ $(PYTHON) $(..)scripts/tst-elf-edit.py --maximize-tls-size $@
+
+$(objpfx)tst-tls-allocation-failure-static-patched.out: \
+ $(objpfx)tst-tls-allocation-failure-static-patched
+ $< > $@ 2>&1; echo "status: $$?" >> $@
+ grep -q '^Fatal glibc error: Cannot allocate TLS block$$' $@ \
+ && grep -q '^status: 127$$' $@; \
+ $(evaluate-test)
diff --git a/elf/dl-early_allocate.c b/elf/dl-early_allocate.c
new file mode 100644
index 0000000000000000..61677aaa0364c209
--- /dev/null
+++ b/elf/dl-early_allocate.c
@@ -0,0 +1,30 @@
+/* Early memory allocation for the dynamic loader. Generic version.
+ 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 <ldsodefs.h>
+#include <stddef.h>
+#include <unistd.h>
+
+void *
+_dl_early_allocate (size_t size)
+{
+ void *result = __sbrk (size);
+ if (result == (void *) -1)
+ result = NULL;
+ return result;
+}
diff --git a/elf/tst-tls-allocation-failure-static.c b/elf/tst-tls-allocation-failure-static.c
new file mode 100644
index 0000000000000000..8de831b2469ba390
--- /dev/null
+++ b/elf/tst-tls-allocation-failure-static.c
@@ -0,0 +1,31 @@
+/* Base for test program with impossiblyh large PT_TLS segment.
+ 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/>. */
+
+/* The test actual binary is patched using scripts/tst-elf-edit.py
+ --maximize-tls-size, and this introduces the expected test
+ allocation failure due to an excessive PT_LS p_memsz value.
+
+ Patching the binary is required because on some 64-bit targets, TLS
+ relocations can only cover a 32-bit range, and glibc-internal TLS
+ variables such as errno end up outside that range. */
+
+int
+main (void)
+{
+ return 0;
+}
diff --git a/scripts/tst-elf-edit.py b/scripts/tst-elf-edit.py
new file mode 100644
index 0000000000000000..0e19ce1e7392f3ca
--- /dev/null
+++ b/scripts/tst-elf-edit.py
@@ -0,0 +1,226 @@
+#!/usr/bin/python3
+# ELF editor for load align tests.
+# Copyright (C) 2022 Free Software Foundation, Inc.
+# Copyright The GNU Toolchain Authors.
+# 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/>.
+
+import argparse
+import os
+import sys
+import struct
+
+EI_NIDENT=16
+
+EI_MAG0=0
+ELFMAG0=b'\x7f'
+EI_MAG1=1
+ELFMAG1=b'E'
+EI_MAG2=2
+ELFMAG2=b'L'
+EI_MAG3=3
+ELFMAG3=b'F'
+
+EI_CLASS=4
+ELFCLASSNONE=b'0'
+ELFCLASS32=b'\x01'
+ELFCLASS64=b'\x02'
+
+EI_DATA=5
+ELFDATA2LSB=b'\x01'
+ELFDATA2MSB=b'\x02'
+
+ET_EXEC=2
+ET_DYN=3
+
+PT_LOAD=1
+PT_TLS=7
+
+def elf_types_fmts(e_ident):
+ endian = '<' if e_ident[EI_DATA] == ELFDATA2LSB else '>'
+ addr = 'I' if e_ident[EI_CLASS] == ELFCLASS32 else 'Q'
+ off = 'I' if e_ident[EI_CLASS] == ELFCLASS32 else 'Q'
+ return (endian, addr, off)
+
+class Elf_Ehdr:
+ def __init__(self, e_ident):
+ endian, addr, off = elf_types_fmts(e_ident)
+ self.fmt = '{0}HHI{1}{2}{2}IHHHHHH'.format(endian, addr, off)
+ self.len = struct.calcsize(self.fmt)
+
+ def read(self, f):
+ buf = f.read(self.len)
+ if not buf:
+ error('{}: header too small'.format(f.name))
+ data = struct.unpack(self.fmt, buf)
+ self.e_type = data[0]
+ self.e_machine = data[1]
+ self.e_version = data[2]
+ self.e_entry = data[3]
+ self.e_phoff = data[4]
+ self.e_shoff = data[5]
+ self.e_flags = data[6]
+ self.e_ehsize = data[7]
+ self.e_phentsize= data[8]
+ self.e_phnum = data[9]
+ self.e_shstrndx = data[10]
+
+
+class Elf_Phdr:
+ def __init__(self, e_ident):
+ endian, addr, off = elf_types_fmts(e_ident)
+ self.ei_class = e_ident[EI_CLASS]
+ if self.ei_class == ELFCLASS32:
+ self.fmt = '{0}I{2}{1}{1}IIII'.format(endian, addr, off)
+ else:
+ self.fmt = '{0}II{2}{1}{1}QQQ'.format(endian, addr, off)
+ self.len = struct.calcsize(self.fmt)
+
+ def read(self, f):
+ buf = f.read(self.len)
+ if len(buf) < self.len:
+ error('{}: program header too small'.format(f.name))
+ data = struct.unpack(self.fmt, buf)
+ if self.ei_class == ELFCLASS32:
+ self.p_type = data[0]
+ self.p_offset = data[1]
+ self.p_vaddr = data[2]
+ self.p_paddr = data[3]
+ self.p_filesz = data[4]
+ self.p_memsz = data[5]
+ self.p_flags = data[6]
+ self.p_align = data[7]
+ else:
+ self.p_type = data[0]
+ self.p_flags = data[1]
+ self.p_offset = data[2]
+ self.p_vaddr = data[3]
+ self.p_paddr = data[4]
+ self.p_filesz = data[5]
+ self.p_memsz = data[6]
+ self.p_align = data[7]
+
+ def write(self, f):
+ if self.ei_class == ELFCLASS32:
+ data = struct.pack(self.fmt,
+ self.p_type,
+ self.p_offset,
+ self.p_vaddr,
+ self.p_paddr,
+ self.p_filesz,
+ self.p_memsz,
+ self.p_flags,
+ self.p_align)
+ else:
+ data = struct.pack(self.fmt,
+ self.p_type,
+ self.p_flags,
+ self.p_offset,
+ self.p_vaddr,
+ self.p_paddr,
+ self.p_filesz,
+ self.p_memsz,
+ self.p_align)
+ f.write(data)
+
+
+def error(msg):
+ print(msg, file=sys.stderr)
+ sys.exit(1)
+
+
+def elf_edit_align(phdr, align):
+ if align == 'half':
+ phdr.p_align = phdr.p_align >> 1
+ else:
+ phdr.p_align = int(align)
+
+def elf_edit_maximize_tls_size(phdr, elfclass):
+ if elfclass == ELFCLASS32:
+ # It is possible that the kernel can allocate half of the
+ # address space, so use something larger.
+ phdr.p_memsz = 0xfff00000
+ else:
+ phdr.p_memsz = 1 << 63
+
+def elf_edit(f, opts):
+ ei_nident_fmt = 'c' * EI_NIDENT
+ ei_nident_len = struct.calcsize(ei_nident_fmt)
+
+ data = f.read(ei_nident_len)
+ if len(data) < ei_nident_len:
+ error('{}: e_nident too small'.format(f.name))
+ e_ident = struct.unpack(ei_nident_fmt, data)
+
+ if e_ident[EI_MAG0] != ELFMAG0 \
+ or e_ident[EI_MAG1] != ELFMAG1 \
+ or e_ident[EI_MAG2] != ELFMAG2 \
+ or e_ident[EI_MAG3] != ELFMAG3:
+ error('{}: bad ELF header'.format(f.name))
+
+ if e_ident[EI_CLASS] != ELFCLASS32 \
+ and e_ident[EI_CLASS] != ELFCLASS64:
+ error('{}: unsupported ELF class: {}'.format(f.name, e_ident[EI_CLASS]))
+
+ if e_ident[EI_DATA] != ELFDATA2LSB \
+ and e_ident[EI_DATA] != ELFDATA2MSB: \
+ error('{}: unsupported ELF data: {}'.format(f.name, e_ident[EI_DATA]))
+
+ ehdr = Elf_Ehdr(e_ident)
+ ehdr.read(f)
+ if ehdr.e_type not in (ET_EXEC, ET_DYN):
+ error('{}: not an executable or shared library'.format(f.name))
+
+ phdr = Elf_Phdr(e_ident)
+ maximize_tls_size_done = False
+ for i in range(0, ehdr.e_phnum):
+ f.seek(ehdr.e_phoff + i * phdr.len)
+ phdr.read(f)
+ if phdr.p_type == PT_LOAD and opts.align is not None:
+ elf_edit_align(phdr, opts.align)
+ f.seek(ehdr.e_phoff + i * phdr.len)
+ phdr.write(f)
+ break
+ if phdr.p_type == PT_TLS and opts.maximize_tls_size:
+ elf_edit_maximize_tls_size(phdr, e_ident[EI_CLASS])
+ f.seek(ehdr.e_phoff + i * phdr.len)
+ phdr.write(f)
+ maximize_tls_size_done = True
+ break
+
+ if opts.maximize_tls_size and not maximize_tls_size_done:
+ error('{}: TLS maximum size was not updated'.format(f.name))
+
+def get_parser():
+ parser = argparse.ArgumentParser(description=__doc__)
+ parser.add_argument('-a', dest='align',
+ help='How to set the LOAD alignment')
+ parser.add_argument('--maximize-tls-size', action='store_true',
+ help='Set maximum PT_TLS size')
+ parser.add_argument('output',
+ help='ELF file to edit')
+ return parser
+
+
+def main(argv):
+ parser = get_parser()
+ opts = parser.parse_args(argv)
+ with open(opts.output, 'r+b') as fout:
+ elf_edit(fout, opts)
+
+
+if __name__ == '__main__':
+ main(sys.argv[1:])
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index a38de94bf7ea8e93..87ad2f3f4d89eb7d 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1238,6 +1238,11 @@ extern struct link_map * _dl_get_dl_main_map (void)
/* Initialize the DSO sort algorithm to use. */
extern void _dl_sort_maps_init (void) attribute_hidden;
+/* Perform early memory allocation, avoding a TCB dependency.
+ Terminate the process if allocation fails. May attempt to use
+ brk. */
+void *_dl_early_allocate (size_t size) attribute_hidden;
+
/* Initialization of libpthread for statically linked applications.
If libpthread is not linked in, this is an empty function. */
void __pthread_initialize_minimal (void) weak_function;
diff --git a/sysdeps/unix/sysv/linux/dl-early_allocate.c b/sysdeps/unix/sysv/linux/dl-early_allocate.c
new file mode 100644
index 0000000000000000..52c538e85afa8522
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/dl-early_allocate.c
@@ -0,0 +1,82 @@
+/* Early memory allocation for the dynamic loader. Generic version.
+ 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/>. */
+
+/* Mark symbols hidden in static PIE for early self relocation to work. */
+#if BUILD_PIE_DEFAULT
+# pragma GCC visibility push(hidden)
+#endif
+#include <startup.h>
+
+#include <ldsodefs.h>
+#include <stddef.h>
+#include <string.h>
+#include <sysdep.h>
+#include <unistd.h>
+
+#include <brk_call.h>
+#include <mmap_call.h>
+
+/* Defined in brk.c. */
+extern void *__curbrk;
+
+void *
+_dl_early_allocate (size_t size)
+{
+ void *result;
+
+ if (__curbrk != NULL)
+ /* If the break has been initialized, brk must have run before,
+ so just call it once more. */
+ {
+ result = __sbrk (size);
+ if (result == (void *) -1)
+ result = NULL;
+ }
+ else
+ {
+ /* If brk has not been invoked, there is no need to update
+ __curbrk. The first call to brk will take care of that. */
+ void *previous = __brk_call (0);
+ result = __brk_call (previous + size);
+ if (result == previous)
+ result = NULL;
+ else
+ result = previous;
+ }
+
+ /* If brk fails, fall back to mmap. This can happen due to
+ unfortunate ASLR layout decisions and kernel bugs, particularly
+ for static PIE. */
+ if (result == NULL)
+ {
+ long int ret;
+ int prot = PROT_READ | PROT_WRITE;
+ int flags = MAP_PRIVATE | MAP_ANONYMOUS;
+#ifdef __NR_mmap2
+ ret = MMAP_CALL_INTERNAL (mmap2, 0, size, prot, flags, -1, 0);
+#else
+ ret = MMAP_CALL_INTERNAL (mmap, 0, size, prot, flags, -1, 0);
+#endif
+ if (INTERNAL_SYSCALL_ERROR_P (ret))
+ result = NULL;
+ else
+ result = (void *) ret;
+ }
+
+ return result;
+}