Use this as extra protection for the guest mapping over
any qemu host mappings.
Tested-by: Helge Deller <del...@gmx.de>
Reviewed-by: Helge Deller <del...@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.od...@daynix.com>
Signed-off-by: Richard Henderson <richard.hender...@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 2aee2298ec..0c64aad8a5 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3146,8 +3146,11 @@ 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
@@ -3159,7 +3162,7 @@ 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
