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Made the mprotect() fix for SDL_SoftStretch() more general for harden…
…ed linux, etc.
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slouken committed Dec 29, 2007
1 parent 3702444 commit a58fc51
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Showing 3 changed files with 34 additions and 30 deletions.
8 changes: 4 additions & 4 deletions configure.in
Expand Up @@ -16,9 +16,9 @@ dnl Set various version strings - taken gratefully from the GTk sources
#
SDL_MAJOR_VERSION=1
SDL_MINOR_VERSION=2
SDL_MICRO_VERSION=12
SDL_INTERFACE_AGE=1
SDL_BINARY_AGE=12
SDL_MICRO_VERSION=13
SDL_INTERFACE_AGE=2
SDL_BINARY_AGE=13
SDL_VERSION=$SDL_MAJOR_VERSION.$SDL_MINOR_VERSION.$SDL_MICRO_VERSION

AC_SUBST(SDL_MAJOR_VERSION)
Expand Down Expand Up @@ -146,7 +146,7 @@ if test x$enable_libc = xyes; then
if test x$ac_cv_func_strtod = xyes; then
AC_DEFINE(HAVE_STRTOD)
fi
AC_CHECK_FUNCS(malloc calloc realloc free getenv putenv unsetenv qsort abs bcopy memset memcpy memmove strlen strlcpy strlcat strdup _strrev _strupr _strlwr strchr strrchr strstr itoa _ltoa _uitoa _ultoa strtol strtoul _i64toa _ui64toa strtoll strtoull atoi atof strcmp strncmp _stricmp strcasecmp _strnicmp strncasecmp sscanf snprintf vsnprintf iconv sigaction setjmp nanosleep)
AC_CHECK_FUNCS(malloc calloc realloc free getenv putenv unsetenv qsort abs bcopy memset memcpy memmove strlen strlcpy strlcat strdup _strrev _strupr _strlwr strchr strrchr strstr itoa _ltoa _uitoa _ultoa strtol strtoul _i64toa _ui64toa strtoll strtoull atoi atof strcmp strncmp _stricmp strcasecmp _strnicmp strncasecmp sscanf snprintf vsnprintf iconv sigaction setjmp nanosleep mprotect)

AC_CHECK_LIB(iconv, libiconv_open, [EXTRA_LDFLAGS="$EXTRA_LDFLAGS -liconv"])
AC_CHECK_LIB(m, pow, [EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lm"])
Expand Down
1 change: 1 addition & 0 deletions include/SDL_config.h.in
Expand Up @@ -136,6 +136,7 @@
#undef HAVE_CLOCK_GETTIME
#undef HAVE_DLVSYM
#undef HAVE_GETPAGESIZE
#undef HAVE_MPROTECT

#else
/* We may need some replacement for stdarg.h here */
Expand Down
55 changes: 29 additions & 26 deletions src/video/SDL_stretch.c
Expand Up @@ -42,14 +42,15 @@

#ifdef USE_ASM_STRETCH

/* OpenBSD has non-executable memory by default, so use mprotect() */
#ifdef __OpenBSD__
#define USE_MPROTECT
#endif
#ifdef USE_MPROTECT
#ifdef HAVE_MPROTECT
#include <sys/types.h>
#include <sys/mman.h>
#endif
#ifdef __GNUC__
#define PAGE_ALIGNED __attribute__((__aligned__(4096)))
#else
#define PAGE_ALIGNED
#endif

#if defined(_M_IX86) || defined(i386)
#define PREFIX16 0x66
Expand All @@ -62,14 +63,15 @@
#error Need assembly opcodes for this architecture
#endif

static unsigned char copy_row[4096];
static unsigned char copy_row[4096] PAGE_ALIGNED;

static int generate_rowbytes(int src_w, int dst_w, int bpp)
{
static struct {
int bpp;
int src_w;
int dst_w;
int status;
} last;

int i;
Expand All @@ -80,11 +82,12 @@ static int generate_rowbytes(int src_w, int dst_w, int bpp)
/* See if we need to regenerate the copy buffer */
if ( (src_w == last.src_w) &&
(dst_w == last.dst_w) && (bpp == last.bpp) ) {
return(0);
return(last.status);
}
last.bpp = bpp;
last.src_w = src_w;
last.dst_w = dst_w;
last.status = -1;

switch (bpp) {
case 1:
Expand All @@ -100,9 +103,6 @@ static int generate_rowbytes(int src_w, int dst_w, int bpp)
SDL_SetError("ASM stretch of %d bytes isn't supported\n", bpp);
return(-1);
}
#ifdef USE_MPROTECT
mprotect(copy_row, sizeof(copy_row), PROT_READ|PROT_WRITE|PROT_EXEC);
#endif
pos = 0x10000;
inc = (src_w << 16) / dst_w;
eip = copy_row;
Expand All @@ -122,15 +122,23 @@ static int generate_rowbytes(int src_w, int dst_w, int bpp)
}
*eip++ = RETURN;

/* Verify that we didn't overflow (too late) */
/* Verify that we didn't overflow (too late!!!) */
if ( eip > (copy_row+sizeof(copy_row)) ) {
SDL_SetError("Copy buffer overflow");
return(-1);
}
#ifdef HAVE_MPROTECT
/* Make the code executable */
if ( mprotect(copy_row, sizeof(copy_row), PROT_READ|PROT_WRITE|PROT_EXEC) < 0 ) {
SDL_SetError("Couldn't make copy buffer executable");
return(-1);
}
#endif
last.status = 0;
return(0);
}

#else
#endif /* USE_ASM_STRETCH */

#define DEFINE_COPY_ROW(name, type) \
void name(type *src, int src_w, type *dst, int dst_w) \
Expand All @@ -154,8 +162,6 @@ DEFINE_COPY_ROW(copy_row1, Uint8)
DEFINE_COPY_ROW(copy_row2, Uint16)
DEFINE_COPY_ROW(copy_row4, Uint32)

#endif /* USE_ASM_STRETCH */

/* The ASM code doesn't handle 24-bpp stretch blits */
void copy_row3(Uint8 *src, int src_w, Uint8 *dst, int dst_w)
{
Expand Down Expand Up @@ -195,9 +201,12 @@ int SDL_SoftStretch(SDL_Surface *src, SDL_Rect *srcrect,
Uint8 *dstp;
SDL_Rect full_src;
SDL_Rect full_dst;
#if defined(USE_ASM_STRETCH) && defined(__GNUC__)
#ifdef USE_ASM_STRETCH
SDL_bool use_asm = SDL_TRUE;
#ifdef __GNUC__
int u1, u2;
#endif
#endif /* USE_ASM_STRETCH */
const int bpp = dst->format->BytesPerPixel;

if ( src->format->BitsPerPixel != dst->format->BitsPerPixel ) {
Expand Down Expand Up @@ -266,9 +275,9 @@ int SDL_SoftStretch(SDL_Surface *src, SDL_Rect *srcrect,

#ifdef USE_ASM_STRETCH
/* Write the opcodes for this stretch */
if ( (bpp != 3) &&
if ( (bpp == 3) ||
(generate_rowbytes(srcrect->w, dstrect->w, bpp) < 0) ) {
return(-1);
use_asm = SDL_FALSE;
}
#endif

Expand All @@ -283,11 +292,7 @@ int SDL_SoftStretch(SDL_Surface *src, SDL_Rect *srcrect,
pos -= 0x10000L;
}
#ifdef USE_ASM_STRETCH
switch (bpp) {
case 3:
copy_row3(srcp, srcrect->w, dstp, dstrect->w);
break;
default:
if (use_asm) {
#ifdef __GNUC__
__asm__ __volatile__ (
"call *%4"
Expand All @@ -311,9 +316,8 @@ int SDL_SoftStretch(SDL_Surface *src, SDL_Rect *srcrect,
#else
#error Need inline assembly for this compiler
#endif
break;
}
#else
} else
#endif
switch (bpp) {
case 1:
copy_row1(srcp, srcrect->w, dstp, dstrect->w);
Expand All @@ -330,7 +334,6 @@ int SDL_SoftStretch(SDL_Surface *src, SDL_Rect *srcrect,
(Uint32 *)dstp, dstrect->w);
break;
}
#endif
pos += inc;
}

Expand Down

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