aboutsummaryrefslogtreecommitdiff
path: root/linux-user
diff options
context:
space:
mode:
authorRichard Henderson <richard.henderson@linaro.org>2023-08-03 17:55:28 +0000
committerRichard Henderson <richard.henderson@linaro.org>2023-08-08 13:27:17 -0700
commitad25051bae392ce35437cdf996aedecc0772af2f (patch)
tree2176d2fb97547ddf0e1873419e34d107d814384c /linux-user
parentda2b71fab63f2396396021917eed9d52f33a45c0 (diff)
linux-user: Use MAP_FIXED_NOREPLACE for initial image mmap
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>
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/elfload.c9
1 files 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;