From 10f273da9caa0b7c814f46b76279065a956393af Mon Sep 17 00:00:00 2001 From: Andrew Wesie Date: Fri, 24 Apr 2020 14:55:14 -0500 Subject: [PATCH] ntdll: Track if a WRITECOPY page has been modified. Once a WRITECOPY page is modified, it should be mapped as if it is a normal read-write page. Signed-off-by: Andrew Wesie --- dlls/ntdll/unix/virtual.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/dlls/ntdll/unix/virtual.c b/dlls/ntdll/unix/virtual.c index 5eadabf7dca..58fd4d0edfc 100644 --- a/dlls/ntdll/unix/virtual.c +++ b/dlls/ntdll/unix/virtual.c @@ -122,6 +122,7 @@ struct file_view #define VPROT_GUARD 0x10 #define VPROT_COMMITTED 0x20 #define VPROT_WRITEWATCH 0x40 +#define VPROT_WRITTEN 0x80 /* per-mapping protection flags */ #define VPROT_ARM64EC 0x0100 /* view may contain ARM64EC code */ #define VPROT_SYSTEM 0x0200 /* system view (underlying mmap not under our control) */ @@ -1155,7 +1156,7 @@ static int get_unix_prot( BYTE vprot ) #if defined(__i386__) if (vprot & VPROT_WRITECOPY) { - if (experimental_WRITECOPY()) + if (experimental_WRITECOPY() && !(vprot & VPROT_WRITTEN)) prot = (prot & ~PROT_WRITE) | PROT_READ; else prot |= PROT_WRITE | PROT_READ; @@ -1672,7 +1673,11 @@ static NTSTATUS create_view( struct file_view **view_ret, void *base, size_t siz */ static DWORD get_win32_prot( BYTE vprot, unsigned int map_prot ) { - DWORD ret = VIRTUAL_Win32Flags[vprot & 0x0f]; + DWORD ret; + + if ((vprot & VPROT_WRITECOPY) && (vprot & VPROT_WRITTEN)) + vprot = (vprot & ~VPROT_WRITECOPY) | VPROT_WRITE; + ret = VIRTUAL_Win32Flags[vprot & 0x0f]; if (vprot & VPROT_GUARD) ret |= PAGE_GUARD; if (map_prot & SEC_NOCACHE) ret |= PAGE_NOCACHE; return ret; @@ -1778,16 +1783,29 @@ static void mprotect_range( void *base, size_t size, BYTE set, BYTE clear ) */ static BOOL set_vprot( struct file_view *view, void *base, size_t size, BYTE vprot ) { + int unix_prot; + if (view->protect & VPROT_WRITEWATCH) { /* each page may need different protections depending on write watch flag */ - set_page_vprot_bits( base, size, vprot & ~VPROT_WRITEWATCH, ~vprot & ~VPROT_WRITEWATCH ); + set_page_vprot_bits( base, size, vprot & ~VPROT_WRITEWATCH, ~vprot & ~(VPROT_WRITEWATCH|VPROT_WRITTEN) ); mprotect_range( base, size, 0, 0 ); return TRUE; } + if (enable_write_exceptions && is_vprot_exec_write( vprot )) vprot |= VPROT_WRITEWATCH; - if (mprotect_exec( base, size, get_unix_prot(vprot) )) return FALSE; - set_page_vprot( base, size, vprot ); + unix_prot = get_unix_prot(vprot); + + /* check that we can map this memory with PROT_WRITE since we cannot fail later */ + if (vprot & VPROT_WRITECOPY) + unix_prot |= PROT_WRITE; + + if (mprotect_exec( base, size, unix_prot )) return FALSE; + /* each page may need different protections depending on writecopy */ + set_page_vprot_bits( base, size, vprot, ~vprot & ~VPROT_WRITTEN ); + if (vprot & VPROT_WRITECOPY) + mprotect_range( base, size, 0, 0 ); + return TRUE; } @@ -4093,7 +4111,7 @@ NTSTATUS virtual_handle_fault( EXCEPTION_RECORD *rec, void *stack ) } if (vprot & VPROT_WRITECOPY) { - set_page_vprot_bits( page, page_size, VPROT_WRITE, VPROT_WRITECOPY ); + set_page_vprot_bits( page, page_size, VPROT_WRITE | VPROT_WRITTEN, VPROT_WRITECOPY ); mprotect_range( page, page_size, 0, 0 ); } /* ignore fault if page is writable now */ -- 2.45.2