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From 6818f32f74981d9bccec8afbab37c42b50ab58be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timo=20Ter=C3=A4s?= <timo.teras@iki.fi>
Date: Thu, 4 Jul 2013 15:50:36 +0300
Subject: [RFC PATCH] elfload: load PIE executables to right address
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
PIE images are ET_DYN images. Check first for pinterp_name to make
sure the main executable always is loaded to correct place.
See below for current behaviour of PIE executables:
Reserved 0x7f000000 bytes of guest address space
host mmap_min_addr=0x1000
guest_base 0x7f7cb41d5000
start end size prot
0037f400-003fe400 0007f000 r-x
003fe400-003ff400 00001000 ---
003ff400-003fe400 fffff000 rw-
003fe400-003ff400 00001000 ---
003ff400-003ffc00 00000800 rw-
003ffc00-003fec00 fffff000 r-x
003fec00-003ffc00 00001000 ---
003ffc00-0007f000 ffc7f400 rw-
start_brk 0x00000000
end_code 0x7eff7ac0
start_code 0x7eff7000
start_data 0x7efffac0
end_data 0x7efffc18
start_stack 0x7eff6dc8
brk 0x7efffc34
entry 0x7e799b30
00000000-00005000 ---p 00000000 00:00 0
00005000-00015000 rw-p 00000000 00:00 0
00015000-7e77d000 ---p 00000000 00:00 0
7e77d000-7e7ec000 r-xp 00000000 68:03 14326298 /lib/libc.so
7e7ec000-7e7f3000 ---p 00000000 00:00 0
7e7f3000-7e7f4000 rw-p 0006e000 68:03 14326298 /lib/libc.so
7e7f4000-7e7f6000 rw-p 00000000 00:00 0
7e7f6000-7e7f7000 ---p 00000000 00:00 0
7e7f7000-7eff7000 rw-p 00000000 00:00 0
7eff7000-7eff8000 r-xp 00000000 68:03 9731305 /usr/bin/brk
7eff8000-7efff000 ---p 00000000 00:00 0
7e7f7000-7eff7000 rw-p 00000000 00:00 0 [stack]
Showing how the main binary got loaded to wrong place.
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
---
I assume pinterp_name is only ever set for the main executable.
Quick grep would indicate that this is indeed the case.
linux-user/elfload.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index ddef23e..d6e00cd 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1660,7 +1660,12 @@ static void load_elf_image(const char *image_name, int image_fd,
}
load_addr = loaddr;
- if (ehdr->e_type == ET_DYN) {
+ if (pinterp_name != NULL) {
+ /* This is the main executable. Make sure that the low
+ address does not conflict with MMAP_MIN_ADDR or the
+ QEMU application itself. */
+ probe_guest_base(image_name, loaddr, hiaddr);
+ } else if (ehdr->e_type == ET_DYN) {
/* The image indicates that it can be loaded anywhere. Find a
location that can hold the memory space required. If the
image is pre-linked, LOADDR will be non-zero. Since we do
@@ -1672,11 +1677,6 @@ static void load_elf_image(const char *image_name, int image_fd,
if (load_addr == -1) {
goto exit_perror;
}
- } else if (pinterp_name != NULL) {
- /* This is the main executable. Make sure that the low
- address does not conflict with MMAP_MIN_ADDR or the
- QEMU application itself. */
- probe_guest_base(image_name, loaddr, hiaddr);
}
load_bias = load_addr - loaddr;
--
1.8.3.2
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