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[freetype2] master 009cc15: [sfnt] Handle infinite recursion in bitmap s


From: Werner LEMBERG
Subject: [freetype2] master 009cc15: [sfnt] Handle infinite recursion in bitmap strikes (#46344).
Date: Sat, 31 Oct 2015 16:54:02 +0000

branch: master
commit 009cc15035160eb412cf7d73df34a84af5738c9b
Author: Werner Lemberg <address@hidden>
Commit: Werner Lemberg <address@hidden>

    [sfnt] Handle infinite recursion in bitmap strikes (#46344).
    
    * src/sfnt/ttsbit.c (TT_SBitDecoder_LoadFunc,
    tt_sbit_decoder_load_bitmap, tt_sbit_decoder_load_byte_aligned,
    tt_sbit_decoder_load_bit_aligned, tt_sbit_decoder_load_png): Add
    argument for recursion depth.
    (tt_sbit_decoder_load_compound): Add argument for recursion depth.
    Increase recursion counter for recursive call.
    (tt_sbit_decoder_load_image): Add argument for recursion depth.
    Check recurse depth.
    (tt_face_load_sbit_image): Updated.
---
 ChangeLog         |   14 +++++++++++
 src/sfnt/ttsbit.c |   68 ++++++++++++++++++++++++++++++++++++----------------
 2 files changed, 61 insertions(+), 21 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index a03116b..3804dfa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2015-10-31  Werner Lemberg  <address@hidden>
+
+       [sfnt] Handle infinite recursion in bitmap strikes (#46344).
+
+       * src/sfnt/ttsbit.c (TT_SBitDecoder_LoadFunc,
+       tt_sbit_decoder_load_bitmap, tt_sbit_decoder_load_byte_aligned,
+       tt_sbit_decoder_load_bit_aligned, tt_sbit_decoder_load_png): Add
+       argument for recursion depth.
+       (tt_sbit_decoder_load_compound): Add argument for recursion depth.
+       Increase recursion counter for recursive call.
+       (tt_sbit_decoder_load_image): Add argument for recursion depth.
+       Check recurse depth.
+       (tt_face_load_sbit_image): Updated.
+
 2015-10-29  Werner Lemberg  <address@hidden>
 
        * src/autofit/afhints.c (af_glyph_hints_dump_points): Minor.
diff --git a/src/sfnt/ttsbit.c b/src/sfnt/ttsbit.c
index 6de8757..c0540f3 100644
--- a/src/sfnt/ttsbit.c
+++ b/src/sfnt/ttsbit.c
@@ -608,13 +608,16 @@
   tt_sbit_decoder_load_image( TT_SBitDecoder  decoder,
                               FT_UInt         glyph_index,
                               FT_Int          x_pos,
-                              FT_Int          y_pos );
+                              FT_Int          y_pos,
+                              FT_UInt         recurse_count );
 
-  typedef FT_Error  (*TT_SBitDecoder_LoadFunc)( TT_SBitDecoder  decoder,
-                                                FT_Byte*        p,
-                                                FT_Byte*        plimit,
-                                                FT_Int          x_pos,
-                                                FT_Int          y_pos );
+  typedef FT_Error  (*TT_SBitDecoder_LoadFunc)(
+                      TT_SBitDecoder  decoder,
+                      FT_Byte*        p,
+                      FT_Byte*        plimit,
+                      FT_Int          x_pos,
+                      FT_Int          y_pos,
+                      FT_UInt         recurse_count );
 
 
   static FT_Error
@@ -622,7 +625,8 @@
                                      FT_Byte*        p,
                                      FT_Byte*        limit,
                                      FT_Int          x_pos,
-                                     FT_Int          y_pos )
+                                     FT_Int          y_pos,
+                                     FT_UInt         recurse_count )
   {
     FT_Error    error = FT_Err_Ok;
     FT_Byte*    line;
@@ -630,6 +634,8 @@
     FT_UInt     bit_height, bit_width;
     FT_Bitmap*  bitmap;
 
+    FT_UNUSED( recurse_count );
+
 
     /* check that we can write the glyph into the bitmap */
     bitmap     = decoder->bitmap;
@@ -761,7 +767,8 @@
                                     FT_Byte*        p,
                                     FT_Byte*        limit,
                                     FT_Int          x_pos,
-                                    FT_Int          y_pos )
+                                    FT_Int          y_pos,
+                                    FT_UInt         recurse_count )
   {
     FT_Error    error = FT_Err_Ok;
     FT_Byte*    line;
@@ -770,6 +777,8 @@
     FT_Bitmap*  bitmap;
     FT_UShort   rval;
 
+    FT_UNUSED( recurse_count );
+
 
     /* check that we can write the glyph into the bitmap */
     bitmap     = decoder->bitmap;
@@ -885,7 +894,8 @@
                                  FT_Byte*        p,
                                  FT_Byte*        limit,
                                  FT_Int          x_pos,
-                                 FT_Int          y_pos )
+                                 FT_Int          y_pos,
+                                 FT_UInt         recurse_count )
   {
     FT_Error  error = FT_Err_Ok;
     FT_UInt   num_components, nn;
@@ -919,8 +929,11 @@
 
 
       /* NB: a recursive call */
-      error = tt_sbit_decoder_load_image( decoder, gindex,
-                                          x_pos + dx, y_pos + dy );
+      error = tt_sbit_decoder_load_image( decoder,
+                                          gindex,
+                                          x_pos + dx,
+                                          y_pos + dy,
+                                          recurse_count + 1 );
       if ( error )
         break;
     }
@@ -952,11 +965,14 @@
                             FT_Byte*        p,
                             FT_Byte*        limit,
                             FT_Int          x_pos,
-                            FT_Int          y_pos )
+                            FT_Int          y_pos,
+                            FT_UInt         recurse_count )
   {
     FT_Error  error = FT_Err_Ok;
     FT_ULong  png_len;
 
+    FT_UNUSED( recurse_count );
+
 
     if ( limit - p < 4 )
     {
@@ -998,7 +1014,8 @@
                                FT_ULong        glyph_start,
                                FT_ULong        glyph_size,
                                FT_Int          x_pos,
-                               FT_Int          y_pos )
+                               FT_Int          y_pos,
+                               FT_UInt         recurse_count )
   {
     FT_Error   error;
     FT_Stream  stream = decoder->stream;
@@ -1124,7 +1141,7 @@
           goto Fail;
       }
 
-      error = loader( decoder, p, p_limit, x_pos, y_pos );
+      error = loader( decoder, p, p_limit, x_pos, y_pos, recurse_count );
     }
 
   Fail:
@@ -1139,13 +1156,9 @@
   tt_sbit_decoder_load_image( TT_SBitDecoder  decoder,
                               FT_UInt         glyph_index,
                               FT_Int          x_pos,
-                              FT_Int          y_pos )
+                              FT_Int          y_pos,
+                              FT_UInt         recurse_count )
   {
-    /*
-     *  First, we find the correct strike range that applies to this
-     *  glyph index.
-     */
-
     FT_Byte*  p          = decoder->eblc_base + decoder->strike_index_array;
     FT_Byte*  p_limit    = decoder->eblc_limit;
     FT_ULong  num_ranges = decoder->strike_index_count;
@@ -1153,6 +1166,17 @@
     FT_ULong  image_start = 0, image_end = 0, image_offset;
 
 
+    /* arbitrary recursion limit */
+    if ( recurse_count > 100 )
+    {
+      FT_TRACE4(( "tt_sbit_decoder_load_image:"
+                  " recursion depth exceeded\n" ));
+      goto Failure;
+    }
+
+
+    /* First, we find the correct strike range that applies to this */
+    /* glyph index.                                                 */
     for ( ; num_ranges > 0; num_ranges-- )
     {
       start = FT_NEXT_USHORT( p );
@@ -1317,7 +1341,8 @@
                                         image_start,
                                         image_end,
                                         x_pos,
-                                        y_pos );
+                                        y_pos,
+                                        recurse_count );
 
   Failure:
     return FT_THROW( Invalid_Table );
@@ -1480,6 +1505,7 @@
           error = tt_sbit_decoder_load_image( decoder,
                                               glyph_index,
                                               0,
+                                              0,
                                               0 );
           tt_sbit_decoder_done( decoder );
         }



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