main/qemu: attempt fix linux-user for PIE executables

1 files changed, 89 insertions, 0 deletions

diff --git a/main/qemu/0001-elfload-load-PIE-executables-to-right-address.patch b/main/qemu/0001-elfload-load-PIE-executables-to-right-address.patch
new file mode 100644
index 000000000..1cf0c2bd1
--- /dev/null
+++ b/main/qemu/0001-elfload-load-PIE-executables-to-right-address.patch
@@ -0,0 +1,89 @@
+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
+