[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PULL 04/14] linux-user: Use MAP_FIXED_NOREPLACE for initial image mmap
From: |
Richard Henderson |
Subject: |
[PULL 04/14] linux-user: Use MAP_FIXED_NOREPLACE for initial image mmap |
Date: |
Tue, 8 Aug 2023 14:08:46 -0700 |
Use this as extra protection for the guest mapping over
any qemu host mappings.
Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
linux-user/elfload.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 36e4026f05..1b4bb2d5af 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3147,8 +3147,11 @@ static void load_elf_image(const char *image_name, int
image_fd,
/*
* Reserve address space for all of this.
*
- * In the case of ET_EXEC, we supply MAP_FIXED so that we get
- * exactly the address range that is required.
+ * In the case of ET_EXEC, we supply MAP_FIXED_NOREPLACE so that we get
+ * exactly the address range that is required. Without reserved_va,
+ * the guest address space is not isolated. We have attempted to avoid
+ * conflict with the host program itself via probe_guest_base, but using
+ * MAP_FIXED_NOREPLACE instead of MAP_FIXED provides an extra check.
*
* Otherwise this is ET_DYN, and we are searching for a location
* that can hold the memory space required. If the image is
@@ -3160,7 +3163,7 @@ static void load_elf_image(const char *image_name, int
image_fd,
*/
load_addr = target_mmap(loaddr, (size_t)hiaddr - loaddr + 1, PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_NORESERVE |
- (ehdr->e_type == ET_EXEC ? MAP_FIXED : 0),
+ (ehdr->e_type == ET_EXEC ? MAP_FIXED_NOREPLACE :
0),
-1, 0);
if (load_addr == -1) {
goto exit_mmap;
--
2.34.1
- [PULL 00/14] linux-user image mapping fixes, Richard Henderson, 2023/08/08
- [PULL 01/14] linux-user: Adjust task_unmapped_base for reserved_va, Richard Henderson, 2023/08/08
- [PULL 02/14] linux-user: Define TASK_UNMAPPED_BASE in $guest/target_mman.h, Richard Henderson, 2023/08/08
- [PULL 04/14] linux-user: Use MAP_FIXED_NOREPLACE for initial image mmap,
Richard Henderson <=
- [PULL 03/14] linux-user: Define ELF_ET_DYN_BASE in $guest/target_mman.h, Richard Henderson, 2023/08/08
- [PULL 05/14] linux-user: Use elf_et_dyn_base for ET_DYN with interpreter, Richard Henderson, 2023/08/08
- [PULL 06/14] linux-user: Adjust initial brk when interpreter is close to executable, Richard Henderson, 2023/08/08
- [PULL 07/14] linux-user: Do not adjust image mapping for host page size, Richard Henderson, 2023/08/08
- [PULL 08/14] linux-user: Do not adjust zero_bss for host page size, Richard Henderson, 2023/08/08
- [PULL 09/14] linux-user: Use zero_bss for PT_LOAD with no file contents too, Richard Henderson, 2023/08/08
- [PULL 10/14] util/selfmap: Rewrite using qemu/interval-tree.h, Richard Henderson, 2023/08/08
- [PULL 11/14] linux-user: Remove duplicate CPU_LOG_PAGE from probe_guest_base, Richard Henderson, 2023/08/08
- [PULL 12/14] linux-user: Consolidate guest bounds check in probe_guest_base, Richard Henderson, 2023/08/08
- [PULL 13/14] linux-user: Rewrite fixed probe_guest_base, Richard Henderson, 2023/08/08