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-rw-r--r--linux-user/elfload.c1
-rw-r--r--linux-user/flatload.c1
-rw-r--r--linux-user/qemu.h1
-rw-r--r--linux-user/syscall.c11
4 files changed, 14 insertions, 0 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 2d920f2017..accb44d9de 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1018,6 +1018,7 @@ static abi_ulong setup_arg_pages(abi_ulong p, struct linux_binprm *bprm,
/* we reserve one extra page at the top of the stack as guard */
target_mprotect(error + size, qemu_host_page_size, PROT_NONE);
+ info->stack_limit = error;
stack_base = error + size - MAX_ARG_PAGES*TARGET_PAGE_SIZE;
p += stack_base;
diff --git a/linux-user/flatload.c b/linux-user/flatload.c
index 914de1f888..8ad130a2bd 100644
--- a/linux-user/flatload.c
+++ b/linux-user/flatload.c
@@ -802,6 +802,7 @@ int load_flt_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
info->end_data = libinfo[0].end_data;
info->start_brk = libinfo[0].start_brk;
info->start_stack = sp;
+ info->stack_limit = libinfo[0].start_brk;
info->entry = start_addr;
info->code_offset = info->start_code;
info->data_offset = info->start_data - libinfo[0].text_len;
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index dab3597cc6..1878d5a61e 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -42,6 +42,7 @@ struct image_info {
abi_ulong mmap;
abi_ulong rss;
abi_ulong start_stack;
+ abi_ulong stack_limit;
abi_ulong entry;
abi_ulong code_offset;
abi_ulong data_offset;
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e94f1eed5c..0ebe7e1c26 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5400,6 +5400,17 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
ret = get_errno(target_munmap(arg1, arg2));
break;
case TARGET_NR_mprotect:
+ {
+ TaskState *ts = ((CPUState *)cpu_env)->opaque;
+ /* Special hack to detect libc making the stack executable. */
+ if ((arg3 & PROT_GROWSDOWN)
+ && arg1 >= ts->info->stack_limit
+ && arg1 <= ts->info->start_stack) {
+ arg3 &= ~PROT_GROWSDOWN;
+ arg2 = arg2 + arg1 - ts->info->stack_limit;
+ arg1 = ts->info->stack_limit;
+ }
+ }
ret = get_errno(target_mprotect(arg1, arg2, arg3));
break;
#ifdef TARGET_NR_mremap