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| author | Paul Brook <paul@codesourcery.com> | 2010-06-16 13:03:51 +0100 |
|---|---|---|
| committer | Paul Brook <paul@codesourcery.com> | 2010-06-16 13:03:51 +0100 |
| commit | 97374d38583028b33074c69caf296d94cb1b9d5b (patch) | |
| tree | 20dd2e75e0b7dcf623a084e19e3f5e39a9161f31 /linux-user/syscall.c | |
| parent | 9e0b74a43f5ab94acdc5b450747b8f6c184e0062 (diff) | |
| download | qemu-97374d38583028b33074c69caf296d94cb1b9d5b.tar.gz | |
Usermode exec-stack fix
When loading a shared library that requires an executable stack,
glibc uses the mprotext PROT_GROWSDOWN flag to achieve this.
We don't support PROT_GROWSDOWN.
Add a special case to handle changing the stack permissions in this way.
Signed-off-by: Paul Brook <paul@codesourcery.com>
Diffstat (limited to 'linux-user/syscall.c')
| -rw-r--r-- | linux-user/syscall.c | 11 |
1 files changed, 11 insertions, 0 deletions
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 |