bb#1778

ChangeLog

@@ -1,3 +1,7 @@
+Fri Jan 22 11:49:07 CET 2010 (acab)
+-----------------------------------
+ * libclamav: fix shifts >= width (bb#1778)
+
 Thu Jan 21 23:01:34 CET 2010 (tk)
 ---------------------------------
  * sigtool: create digitally signed .info files

libclamav/disasm.c

@@ -1545,8 +1545,10 @@ static const uint8_t *disasm_x86(const uint8_t *command, unsigned int len, struc
 	    GETBYTE(b);
 	    shiftme+=b<<(i*8);
 	  }
-	  shiftme<<=((8-mod)*8);
-	  s->args[reversed].arg.marg.disp=shiftme>>((8-mod)*8);
+	  if(mod) {
+	      shiftme<<=((8-mod)*8);
+	      s->args[reversed].arg.marg.disp=shiftme>>((8-mod)*8);
+	  } else s->args[reversed].arg.marg.disp=0;
 	} else {
 	  if (mod==0 && rm==6) {
 	    s->args[reversed].arg.marg.r1=REG_INVALID;

libclamav/others.h

@@ -380,8 +380,10 @@ static inline void cli_writeint32(char *offset, uint32_t value)
 #endif
 
 /* used by: spin, yc (C) aCaB */
-#define CLI_ROL(a,b) a = ( a << (b % (sizeof(a)<<3) ))  |  (a >> (  (sizeof(a)<<3)  -  (b % (sizeof(a)<<3 )) ) )
-#define CLI_ROR(a,b) a = ( a >> (b % (sizeof(a)<<3) ))  |  (a << (  (sizeof(a)<<3)  -  (b % (sizeof(a)<<3 )) ) )
+#define __SHIFTBITS(a) (sizeof(a)<<3)
+#define __SHIFTMASK(a) (__SHIFTBITS(a)-1)
+#define CLI_ROL(a,b) a = ( a << (b & __SHIFTMASK(a)) ) | ( a >> ((__SHIFTBITS(a) - b) & __SHIFTMASK(a)) )
+#define CLI_ROR(a,b) a = ( a >> (b & __SHIFTMASK(a)) ) | ( a << ((__SHIFTBITS(a) - b) & __SHIFTMASK(a))
 
 /* Implementation independent sign-extended signed right shift */
 #ifdef HAVE_SAR