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Commit 30c5db2f authored by Ivan Lozano's avatar Ivan Lozano
Browse files

Add minimal-runtime support for integer overflows. 

Adds Soong support for -fsanitze-minimal-runtime when using
the integer overflow sanitizers. This makes the crashes due to these
sanitizers less mysterious.

Bug: 64091660
Test: Compiled and checked the generated compiler commands
Test: Checked program that overflows for the abort reason

Change-Id: Ieeceaf6c35c8371592952d3b8b977aefc11601c5
parent d4bc5562

cc/cc.go

+2 −0
Original line number Diff line number Diff line
@@ -52,6 +52,8 @@ func init() { 
		ctx.TopDown("tsan_deps", sanitizerDepsMutator(tsan))

		ctx.BottomUp("tsan", sanitizerMutator(tsan)).Parallel()



		ctx.TopDown("minimal_runtime_deps", minimalRuntimeDepsMutator())



		ctx.BottomUp("coverage", coverageLinkingMutator).Parallel()

		ctx.TopDown("vndk_deps", sabiDepsMutator)

cc/config/toolchain.go

+4 −0
Original line number Diff line number Diff line
@@ -215,6 +215,10 @@ func UndefinedBehaviorSanitizerRuntimeLibrary(t Toolchain) string { 
	return SanitizerRuntimeLibrary(t, "ubsan_standalone")

}



func UndefinedBehaviorSanitizerMinimalRuntimeLibrary(t Toolchain) string {

	return SanitizerRuntimeLibrary(t, "ubsan_minimal")

}



func ThreadSanitizerRuntimeLibrary(t Toolchain) string {

	return SanitizerRuntimeLibrary(t, "tsan")

}

cc/makevars.go

+1 −0
Original line number Diff line number Diff line
@@ -276,6 +276,7 @@ func makeVarsToolchain(ctx android.MakeVarsContext, secondPrefix string, 
		if target.Os.Class == android.Device {

			ctx.Strict(secondPrefix+"ADDRESS_SANITIZER_RUNTIME_LIBRARY", strings.TrimSuffix(config.AddressSanitizerRuntimeLibrary(toolchain), ".so"))

			ctx.Strict(secondPrefix+"UBSAN_RUNTIME_LIBRARY", strings.TrimSuffix(config.UndefinedBehaviorSanitizerRuntimeLibrary(toolchain), ".so"))

			ctx.Strict(secondPrefix+"UBSAN_MINIMAL_RUNTIME_LIBRARY", strings.TrimSuffix(config.UndefinedBehaviorSanitizerMinimalRuntimeLibrary(toolchain), ".a"))

			ctx.Strict(secondPrefix+"TSAN_RUNTIME_LIBRARY", strings.TrimSuffix(config.ThreadSanitizerRuntimeLibrary(toolchain), ".so"))

		}

cc/sanitize.go

+47 −4
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ var ( 
	cfiStaticLibsMutex sync.Mutex



	intOverflowCflags   = []string{"-fsanitize-blacklist=build/soong/cc/config/integer_overflow_blacklist.txt"}

	minimalRuntimeFlags = []string{"-fsanitize-minimal-runtime", "-fno-sanitize-trap=integer", "-fno-sanitize-recover=integer"}

)



type sanitizerType int
@@ -114,6 +115,7 @@ type SanitizeProperties struct { 


	SanitizerEnabled  bool `blueprint:"mutated"`

	SanitizeDep       bool `blueprint:"mutated"`

	MinimalRuntimeDep bool `blueprint:"mutated"`

	InSanitizerDir    bool `blueprint:"mutated"`

}
@@ -301,6 +303,11 @@ func (sanitize *sanitize) deps(ctx BaseModuleContext, deps Deps) Deps { 
}



func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags {

	minimalRuntimePath := "${config.ClangAsanLibDir}/" + config.UndefinedBehaviorSanitizerMinimalRuntimeLibrary(ctx.toolchain()) + ".a"



	if ctx.Device() && sanitize.Properties.MinimalRuntimeDep {

		flags.LdFlags = append(flags.LdFlags, minimalRuntimePath)

	}

	if !sanitize.Properties.SanitizerEnabled {

		return flags

	}
@@ -431,6 +438,7 @@ func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags { 


	if len(sanitizers) > 0 {

		sanitizeArg := "-fsanitize=" + strings.Join(sanitizers, ",")



		flags.CFlags = append(flags.CFlags, sanitizeArg)

		if ctx.Host() {

			flags.CFlags = append(flags.CFlags, "-fno-sanitize-recover=all")
@@ -440,6 +448,11 @@ func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags { 
			_, flags.LdFlags = removeFromList("-Wl,--no-undefined", flags.LdFlags)

		} else {

			flags.CFlags = append(flags.CFlags, "-fsanitize-trap=all", "-ftrap-function=abort")



			if enableMinimalRuntime(sanitize) {

				flags.CFlags = append(flags.CFlags, strings.Join(minimalRuntimeFlags, " "))

				flags.libFlags = append([]string{minimalRuntimePath}, flags.libFlags...)

			}

		}

	}
@@ -589,6 +602,24 @@ func sanitizerDepsMutator(t sanitizerType) func(android.TopDownMutatorContext) { 
	}

}



// Propagate the ubsan minimal runtime dependency when there are integer overflow sanitized static dependencies.

func minimalRuntimeDepsMutator() func(android.TopDownMutatorContext) {

	return func(mctx android.TopDownMutatorContext) {

		if c, ok := mctx.Module().(*Module); ok && c.sanitize != nil {

			mctx.VisitDepsDepthFirst(func(module android.Module) {

				if d, ok := module.(*Module); ok && d.static() && d.sanitize != nil {



					// If a static dependency will be built with the minimal runtime,

					// make sure we include the ubsan minimal runtime.

					if enableMinimalRuntime(d.sanitize) {

						c.sanitize.Properties.MinimalRuntimeDep = true

					}

				}

			})

		}

	}

}



// Create sanitized variants for modules that need them

func sanitizerMutator(t sanitizerType) func(android.BottomUpMutatorContext) {

	return func(mctx android.BottomUpMutatorContext) {
@@ -659,6 +690,18 @@ func cfiStaticLibs(config android.Config) *[]string { 
	}).(*[]string)

}



func enableMinimalRuntime(sanitize *sanitize) bool {

	if !Bool(sanitize.Properties.Sanitize.Address) &&

		(Bool(sanitize.Properties.Sanitize.Integer_overflow) ||

			len(sanitize.Properties.Sanitize.Misc_undefined) > 0) &&

		!(Bool(sanitize.Properties.Sanitize.Diag.Integer_overflow) ||

			Bool(sanitize.Properties.Sanitize.Diag.Cfi) ||

			len(sanitize.Properties.Sanitize.Diag.Misc_undefined) > 0) {

		return true

	}

	return false

}



func cfiMakeVarsProvider(ctx android.MakeVarsContext) {

	cfiStaticLibs := cfiStaticLibs(ctx.Config())

	sort.Strings(*cfiStaticLibs)