From 7e4d79464adc3140b03f6e92a902d061c99b9ebe Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 4 May 2012 22:51:59 -0400 Subject: [PATCH] make pthread stacks non-executable this change is necessary or pthread_create will always fail on security-hardened kernels. i considered first trying to make the stack executable and simply retrying without execute permissions when the first try fails, but (1) this would incur a serious performance penalty on hardened systems, and (2) having the stack be executable is just a bad idea from a security standpoint. if there is real-world "GNU C" code that uses nested functions with threads, and it can't be fixed, we'll have to consider other ways of solving the problem, but for now this seems like the best fix. --- src/thread/pthread_create.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index c3b65ae9..917be54f 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -104,7 +104,7 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE); } size += __pthread_tsd_size; - map = mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0); + map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0); if (map == MAP_FAILED) return EAGAIN; if (guard) mprotect(map, guard, PROT_NONE); -- 2.20.1