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2013-03-12

2013-03-12 22:42:10 by Arne Goedeke <el@laramies.com>

pike_memory: add guaranteed_memset()

Most compilers (gcc in recent versions) optimize away memset before
free. This can prevent sensitive data from being wiped.

8:   #include "operators.h"   #include "module_support.h"   #include "threads.h" + #include "pike_memory.h"      #include "nettle_config.h"   
399:    free_object(THIS->object);    }    if(THIS->iv) { -  MEMSET(THIS->iv, 0, THIS->block_size); +  guaranteed_memset(THIS->iv, 0, THIS->block_size);    free(THIS->iv);    }    }
479:    Pike_error("Bad block size %d.\n", THIS->block_size);       if(THIS->iv) { -  MEMSET(THIS->iv, 0, old_block_size); +  guaranteed_memset(THIS->iv, 0, old_block_size);    free(THIS->iv);    }    THIS->iv = (unsigned INT8 *)xalloc(THIS->block_size);
594:       pop_n_elems(args);    push_string(make_shared_binary_string((INT8 *)result, offset)); -  MEMSET(result, 0, offset); +  guaranteed_memset(result, 0, offset);       CALL_AND_UNSET_ONERROR (uwp);    }
625:    gc_trivial;    {    if(THIS->backlog) { -  MEMSET(THIS->backlog, 0, THIS->block_size); +  guaranteed_memset(THIS->backlog, 0, THIS->block_size);    free(THIS->backlog);    THIS->backlog = NULL;    }
810:    pop_n_elems(args);       push_string(make_shared_binary_string((char *)result, roffset + len)); -  MEMSET(result, 0, roffset + len); +  guaranteed_memset(result, 0, roffset + len);    CALL_AND_UNSET_ONERROR (uwp);    }