From b2854b0bcc5ffeeeadd3209c46d89eca78ce43a3 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Mon, 24 Oct 2022 16:18:42 +0100 Subject: cheri: nptl: Fix thread stack capability permissions --- nptl/allocatestack.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index 219854f..755ace5 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -52,6 +52,13 @@ # define MAP_STACK 0 #endif +/* On CHERI targets ensure the mmap returned capability has RW permissions. */ +#ifdef PROT_MAX +# define PROT_MAX_RW PROT_MAX (PROT_READ | PROT_WRITE) +#else +# define PROT_MAX_RW 0 +#endif + /* Get a stack frame from the cache. We have to match by size since some blocks might be too small or far too large. */ static struct pthread * @@ -363,7 +370,8 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, /* If a guard page is required, avoid committing memory by first allocate with PROT_NONE and then reserve with required permission excluding the guard page. */ - mem = __mmap (NULL, size, (guardsize == 0) ? prot : PROT_NONE, + mem = __mmap (NULL, size, + (guardsize == 0) ? prot : PROT_NONE | PROT_MAX_RW, MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); if (__glibc_unlikely (mem == MAP_FAILED)) -- cgit v1.1