Merge pull request #313 from ljxfstorm/f/relro-bitwise-bind-now

fix(relro): use bitwise check for DF_BIND_NOW flag

Author: slimm609

pkg/checksec/relro.go

@@ -31,20 +31,21 @@ func RELRO(name string) *relro {
 		return &res
 	}
 
-	// check both bind and bind_flag.
+	// check both bind and flags.
 	// if DT_BIND_NOW == 0, then it is set
-	// if DT_FLAGS == 8, then DF_BIND_NOW is set
+	// if (DT_FLAGS & 0x8) > 0, then DF_BIND_NOW is set
 	// this is depending on the compiler version used.
 	bind, _ := file.DynValue(elf.DT_BIND_NOW)
 	if len(bind) == 0 {
 		bind, _ = DynValueFromPTDynamic(file, elf.DT_BIND_NOW)
 	}
-	bind_flag, _ := file.DynValue(elf.DT_FLAGS)
-	if len(bind_flag) == 0 {
-		bind_flag, _ = DynValueFromPTDynamic(file, elf.DT_FLAGS)
+	flags, _ := file.DynValue(elf.DT_FLAGS)
+	if len(flags) == 0 {
+		flags, _ = DynValueFromPTDynamic(file, elf.DT_FLAGS)
 	}
 
-	if (len(bind) > 0 && bind[0] == 0) || (len(bind_flag) > 0 && bind_flag[0] == 8) {
+	const DF_BIND_NOW = 0x8
+	if (len(bind) > 0 && bind[0] == 0) || (len(flags) > 0 && (flags[0] & DF_BIND_NOW) > 0) {
 		bindNow = true
 	}