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Fix shadowstack syscall number redefinition #270

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Fix shadowstack syscall number redefinition #270

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73c90bb
Fix __NR_map_shadow_stack redefinition.
Lastique Sep 12, 2024
658379b
Replace tabs with spaces, trim trailing spaces.
Lastique Sep 12, 2024
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27 changes: 15 additions & 12 deletions include/boost/context/fiber_fcontext.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -47,9 +47,12 @@
#if defined(__CET__) && defined(__unix__)
# include <cet.h>
# include <sys/mman.h>
# include <unistd.h>
# define SHSTK_ENABLED (__CET__ & 0x2)
# define BOOST_CONTEXT_SHADOW_STACK (SHSTK_ENABLED && SHADOW_STACK_SYSCALL)
# define __NR_map_shadow_stack 451
# if !defined(__NR_map_shadow_stack)
# define __NR_map_shadow_stack 453
# endif
#ifndef SHADOW_STACK_SET_TOKEN
# define SHADOW_STACK_SET_TOKEN 0x1
#endif
Expand Down Expand Up @@ -168,8 +171,8 @@ template< typename Record, typename StackAlloc, typename Fn >
fcontext_t create_fiber1( StackAlloc && salloc, Fn && fn) {
auto sctx = salloc.allocate();
// reserve space for control structure
void * storage = reinterpret_cast< void * >(
( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( Record) ) )
void * storage = reinterpret_cast< void * >(
( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( Record) ) )
& ~static_cast< uintptr_t >( 0xff) );
// placment new for control structure on context stack
Record * record = new ( storage) Record{
Expand All @@ -186,16 +189,16 @@ fcontext_t create_fiber1( StackAlloc && salloc, Fn && fn) {
#if BOOST_CONTEXT_SHADOW_STACK
std::size_t ss_size = size >> 5;
// align shadow stack to 8 bytes.
ss_size = (ss_size + 7) & ~7;
ss_size = (ss_size + 7) & ~7;
// Todo: shadow stack occupies at least 4KB
ss_size = (ss_size > 4096) ? size : 4096;
// create shadow stack
void *ss_base = (void *)syscall(__NR_map_shadow_stack, 0, ss_size, SHADOW_STACK_SET_TOKEN);
BOOST_ASSERT(ss_base != -1);
unsigned long ss_sp = (unsigned long)ss_base + ss_size;
/* pass the shadow stack pointer to make_fcontext
i.e., link the new shadow stack with the new fcontext
TODO should be a better way? */
i.e., link the new shadow stack with the new fcontext
TODO should be a better way? */
*((unsigned long*)(reinterpret_cast< uintptr_t >( stack_top)- 8)) = ss_sp;
/* Todo: place shadow stack info in 64byte gap */
*((unsigned long*)(reinterpret_cast< uintptr_t >( storage)- 8)) = (unsigned long) ss_base;
Expand Down Expand Up @@ -227,16 +230,16 @@ fcontext_t create_fiber2( preallocated palloc, StackAlloc && salloc, Fn && fn) {
#if BOOST_CONTEXT_SHADOW_STACK
std::size_t ss_size = size >> 5;
// align shadow stack to 8 bytes.
ss_size = (ss_size + 7) & ~7;
ss_size = (ss_size + 7) & ~7;
// Todo: shadow stack occupies at least 4KB
ss_size = (ss_size > 4096) ? size : 4096;
// create shadow stack
void *ss_base = (void *)syscall(__NR_map_shadow_stack, 0, ss_size, SHADOW_STACK_SET_TOKEN);
BOOST_ASSERT(ss_base != -1);
unsigned long ss_sp = (unsigned long)ss_base + ss_size;
/* pass the shadow stack pointer to make_fcontext
i.e., link the new shadow stack with the new fcontext
TODO should be a better way? */
i.e., link the new shadow stack with the new fcontext
TODO should be a better way? */
*((unsigned long*)(reinterpret_cast< uintptr_t >( stack_top)- 8)) = ss_sp;
/* Todo: place shadow stack info in 64byte gap */
*((unsigned long*)(reinterpret_cast< uintptr_t >( storage)- 8)) = (unsigned long) ss_base;
Expand Down Expand Up @@ -359,7 +362,7 @@ class fiber {
}

#if !defined(BOOST_EMBTC)

template< typename charT, class traitsT >
friend std::basic_ostream< charT, traitsT > &
operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other) {
Expand All @@ -371,7 +374,7 @@ class fiber {
}

#else

template< typename charT, class traitsT >
friend std::basic_ostream< charT, traitsT > &
operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other);
Expand All @@ -396,7 +399,7 @@ class fiber {
}

#endif

inline
void swap( fiber & l, fiber & r) noexcept {
l.swap( r);
Expand Down
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