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From cb83c302eb77748a99940fa41026d5f373976478 Mon Sep 17 00:00:00 2001
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From: Paul Eggert <eggert@cs.ucla.edu>
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Date: Mon, 16 Nov 2015 17:48:08 -0800
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Subject: [PATCH 11/11] ELF unexec: align section header
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This ports the recent unexelf.c changes to Fedora x86-64
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when configured with GCC’s -fsanitize=undefined option.
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* src/unexelf.c (unexec): Align new_data2_size to a multiple
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of ElfW (Shdr)’s alignment, so that NEW_SECTION_H returns a
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pointer aligned appropriately for its type.
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---
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src/unexelf.c | 11 ++++++++---
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1 file changed, 8 insertions(+), 3 deletions(-)
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diff --git a/src/unexelf.c b/src/unexelf.c
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index c10c7f2..03e6daf 100644
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--- a/src/unexelf.c
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+++ b/src/unexelf.c
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@@ -247,7 +247,7 @@ unexec (const char *new_name, const char *old_name)
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ElfW (Phdr) *old_bss_seg, *new_bss_seg;
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ElfW (Addr) old_bss_addr, new_bss_addr;
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- ElfW (Word) old_bss_size, new_data2_size;
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+ ElfW (Word) old_bss_size, bss_size_growth, new_data2_size;
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ElfW (Off) old_bss_offset, new_data2_offset;
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ptrdiff_t n;
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@@ -331,7 +331,11 @@ unexec (const char *new_name, const char *old_name)
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new_break = sbrk (0);
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new_bss_addr = (ElfW (Addr)) new_break;
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- new_data2_size = new_bss_addr - old_bss_addr;
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+ bss_size_growth = new_bss_addr - old_bss_addr;
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+ new_data2_size = bss_size_growth;
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+ new_data2_size += alignof (ElfW (Shdr)) - 1;
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+ new_data2_size -= new_data2_size % alignof (ElfW (Shdr));
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+
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new_data2_offset = old_bss_offset;
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#ifdef UNEXELF_DEBUG
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@@ -399,7 +403,8 @@ unexec (const char *new_name, const char *old_name)
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new_bss_seg->p_memsz = new_bss_seg->p_filesz;
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/* Copy over what we have in memory now for the bss area. */
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- memcpy (new_base + new_data2_offset, (caddr_t) old_bss_addr, new_data2_size);
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+ memcpy (new_base + new_data2_offset, (caddr_t) old_bss_addr,
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+ bss_size_growth);
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/* Walk through all section headers, copying data and updating. */
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for (n = 1; n < old_file_h->e_shnum; n++)
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--
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2.7.4
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