From 746ef8e93964a99db3e3fa4b8a7aba179185ef0a Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 5 Mar 2025 10:19:59 +0800 Subject: [PATCH] static-pie: Skip the empty PT_LOAD segment at offset 0 [BZ #32763] As shown in https://sourceware.org/bugzilla/show_bug.cgi?id=25237 linker may generate an empty PT_LOAD segments at offset 0: Elf file type is EXEC (Executable file) Entry point 0x4000e8 There are 3 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000000000 0x0000000000400000 0x0000000000400000 0x00000000000000f0 0x00000000000000f0 R E 0x1000 LOAD 0x0000000000000000 0x0000000000410000 0x0000000000410000 0x0000000000000000 0x0000000000b5dce8 RW 0x10000 GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 RW 0x10 Section to Segment mapping: Segment Sections... 00 .text 01 .bss 02 Skip the empty PT_LOAD segment at offset 0 to support such binaries. This fixes BZ #32763. Signed-off-by: H.J. Lu Reviewed-by: Sam James (cherry picked from commit 596130591ae4b058a529cc1318b95e624559054c) --- elf/Makefile | 5 +++++ elf/dl-reloc-static-pie.c | 3 ++- elf/tst-pie-bss-static.c | 19 +++++++++++++++++++ elf/tst-pie-bss.c | 30 ++++++++++++++++++++++++++++++ 4 files changed, 56 insertions(+), 1 deletion(-) create mode 100644 elf/tst-pie-bss-static.c create mode 100644 elf/tst-pie-bss.c diff --git a/elf/Makefile b/elf/Makefile index 75fc517248..848a8c3077 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -1135,12 +1135,14 @@ tests += \ tst-dlopen-pie \ tst-dlopen-self-pie \ tst-dlopen-tlsmodid-pie \ + tst-pie-bss \ tst-pie1 \ tst-pie2 \ # tests tests-pie += \ tst-dlopen-self-pie \ tst-dlopen-tlsmodid-pie \ + tst-pie-bss \ tst-pie1 \ tst-pie2 \ # tests-pie @@ -1155,9 +1157,11 @@ LDFLAGS-tst-pie-address += $(load-address-ldflag)=$(pde-load-address) ifeq (yes,$(enable-static-pie)) tests += \ tst-pie-address-static \ + tst-pie-bss-static \ # tests tests-static += \ tst-pie-address-static \ + tst-pie-bss-static \ # tests-static LDFLAGS-tst-pie-address-static += \ $(load-address-ldflag)=$(pde-load-address) @@ -2080,6 +2084,7 @@ $(objpfx)tst-array5-static-cmp.out: tst-array5-static.exp \ CFLAGS-tst-pie1.c += $(pie-ccflag) CFLAGS-tst-pie2.c += $(pie-ccflag) +CFLAGS-tst-pie-bss.c += $(pie-ccflag) CFLAGS-tst-pie-address.c += $(pie-ccflag) $(objpfx)tst-piemod1.so: $(libsupport) diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c index e34bf5f7ce..758bf9893e 100644 --- a/elf/dl-reloc-static-pie.c +++ b/elf/dl-reloc-static-pie.c @@ -51,7 +51,8 @@ _dl_relocate_static_pie (void) switch (ph->p_type) { case PT_LOAD: - if (ph->p_offset == 0) + /* Skip the empty PT_LOAD segment at offset 0. */ + if (ph->p_filesz != 0 && ph->p_offset == 0) file_p_vaddr = ph->p_vaddr; break; case PT_DYNAMIC: diff --git a/elf/tst-pie-bss-static.c b/elf/tst-pie-bss-static.c new file mode 100644 index 0000000000..5df542f9ee --- /dev/null +++ b/elf/tst-pie-bss-static.c @@ -0,0 +1,19 @@ +/* Test static PIE with an empty PT_LOAD segment at offset 0. + Copyright (C) 2025 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 + . */ + +#include "tst-pie-bss.c" diff --git a/elf/tst-pie-bss.c b/elf/tst-pie-bss.c new file mode 100644 index 0000000000..ee92754249 --- /dev/null +++ b/elf/tst-pie-bss.c @@ -0,0 +1,30 @@ +/* Test PIE with an empty PT_LOAD segment at offset 0. + Copyright (C) 2025 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 + . */ + +#include + +char bss[0xb5dce8] __attribute__ ((aligned (65536))); + +static int +do_test (void) +{ + printf ("Hello\n"); + return 0; +} + +#include