Commit 0e0863ee authored by Sergei Trofimovich's avatar Sergei Trofimovich
Browse files

zsnes: fix buffer size marking to avoid crash on _FORTIFY_SOURCE=3 

Without the change `zsnesn` startup crashes with:

    $ gdb zsnes
    *** buffer overflow detected ***: terminated
    ...
    #7  0x08057c14 in memset (__len=2, __ch=255, __dest=<optimized out>) at
      ...-glibc-2.38-23-dev/include/bits/string_fortified.h:59
parent ef34e71d

pkgs/applications/emulators/zsnes/default.nix

+4 −1
Original line number Diff line number Diff line
@@ -23,7 +23,10 @@ in stdenv.mkDerivation { 
    sha256 = "1gy79d5wdaacph0cc1amw7mqm7i0716n6mvav16p1svi26iz193v";

  };



  patches = [ ./zlib-1.3.patch ];

  patches = [

    ./zlib-1.3.patch

    ./fortify3.patch

  ];



  buildInputs = [ nasm SDL zlib libpng ncurses libGLU libGL ];

pkgs/applications/emulators/zsnes/fortify3.patch

0 → 100644
+29 −0
Original line number Diff line number Diff line 
pal16bxcl is an array of 256 dwords, not bytes:

    src/endmem.asm:NEWSYM pal16bxcl, resd 256



While at it fixes off-by-4 out of bounds exit.



Detected by _FORTIFY_SOURCE=3:

    *** buffer overflow detected ***: terminated

    #7  0x08057c14 in memset (__len=2, __ch=255, __dest=<optimized out>) at ...-glibc-2.38-23-dev/include/bits/string_fortified.h:59

#8  clearmem () at initc.c:1461

--- a/src/initc.c

+++ b/src/initc.c

@@ -1389,7 +1389,7 @@ extern unsigned char vidmemch8[4096];

 extern unsigned char pal16b[1024];

 extern unsigned char pal16bcl[1024];

 extern unsigned char pal16bclha[1024];

-extern unsigned char pal16bxcl[256];

+extern unsigned char pal16bxcl[1024];

 extern unsigned char SPCRAM[65472];

 unsigned char *SPCState = SPCRAM;

 

@@ -1456,7 +1456,7 @@ void clearmem()

   memset(pal16b, 0, 1024);

   memset(pal16bcl, 0, 1024);

   memset(pal16bclha, 0, 1024);

-  for (i=0 ; i<1024 ; i+=4)

+  for (i=0 ; i<1024-4 ; i+=4)

   {

     memset(pal16bxcl+i, 255, 2);

     memset(pal16bxcl+i+2, 0, 2);