[tor-commits] [sandboxed-tor-browser/master] dynlib: Search the system library path(s) as the last resort.

[yawning at torproject.org]

commit 824c61cf62f15d00a634e8a050512bb8adafc712
Author: Yawning Angel <yawning at schwanenlied.me>
Date:   Tue Feb 20 06:19:52 2018 +0000

    dynlib: Search the system library path(s) as the last resort.
    
    This make the dynlib process more resilient to ld.so.conf having
    oddities in it, and more importantly makes this work on my laptop again.
---
 .../sandboxed-tor-browser/internal/dynlib/cache.go | 47 ++++++++++++++--------
 .../internal/sandbox/application.go                |  4 +-
 2 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/src/cmd/sandboxed-tor-browser/internal/dynlib/cache.go b/src/cmd/sandboxed-tor-browser/internal/dynlib/cache.go
index 24dcf47..c664aa9 100644
--- a/src/cmd/sandboxed-tor-browser/internal/dynlib/cache.go
+++ b/src/cmd/sandboxed-tor-browser/internal/dynlib/cache.go
@@ -84,8 +84,9 @@ func (c *Cache) GetLibraryPath(name string) string {
 // ResolveLibraries returns a map of library paths and their aliases for a
 // given set of binaries, based off the ld.so.cache, libraries known to be
 // internal, and a search path.
-func (c *Cache) ResolveLibraries(binaries []string, extraLibs []string, ldLibraryPath string, filterFn FilterFunc) (map[string][]string, error) {
+func (c *Cache) ResolveLibraries(binaries []string, extraLibs []string, ldLibraryPath, fallbackSearchPath string, filterFn FilterFunc) (map[string][]string, error) {
 	searchPaths := filepath.SplitList(ldLibraryPath)
+	fallbackSearchPaths := filepath.SplitList(fallbackSearchPath)
 	libraries := make(map[string]string)
 
 	// Breadth-first iteration of all the binaries, and their dependencies.
@@ -124,25 +125,39 @@ func (c *Cache) ResolveLibraries(binaries []string, extraLibs []string, ldLibrar
 					continue
 				}
 
-				// Look for the library in the search path.
-				libPath := ""
-				inLdLibraryPath := false
-				for _, d := range searchPaths {
-					maybePath := filepath.Join(d, lib)
-					if FileExists(maybePath) {
-						libPath = maybePath
-						inLdLibraryPath = true
-						break
+				isInPath := func(l string, p []string) string {
+					for _, d := range p {
+						maybePath := filepath.Join(d, l)
+						if FileExists(maybePath) {
+							return maybePath
+						}
 					}
+					return ""
 				}
 
-				// Look for the library in the ld.so.cache.
-				if libPath == "" {
-					libPath = c.GetLibraryPath(lib)
-					if libPath == "" {
-						return nil, fmt.Errorf("dynlib: Failed to find library: %v", lib)
-					}
+				// Look for the library in the various places.
+				var libPath string
+				var inLdLibraryPath, inCache, inFallbackPath bool
+				if libPath = isInPath(lib, searchPaths); libPath != "" {
+					inLdLibraryPath = true
+				} else if libPath = c.GetLibraryPath(lib); libPath != "" {
+					inCache = true
+				} else if libPath = isInPath(lib, fallbackSearchPaths); libPath != "" {
+					inFallbackPath = true
+				} else {
+					return nil, fmt.Errorf("dynlib: Failed to find library: %v", lib)
+				}
+
+				var libSrc string
+				switch {
+				case inLdLibraryPath:
+					libSrc = "LD_LIBRARY_PATH"
+				case inCache:
+					libSrc = "ld.so.conf"
+				case inFallbackPath:
+					libSrc = "Filesystem"
 				}
+				Debugf("dynlib: Found %v (%v).", lib, libSrc)
 
 				// Register the library, assuming it's not in what will
 				// presumably be `LD_LIBRARY_PATH` inside the hugbox.
diff --git a/src/cmd/sandboxed-tor-browser/internal/sandbox/application.go b/src/cmd/sandboxed-tor-browser/internal/sandbox/application.go
index 9d68516..6ba5db8 100644
--- a/src/cmd/sandboxed-tor-browser/internal/sandbox/application.go
+++ b/src/cmd/sandboxed-tor-browser/internal/sandbox/application.go
@@ -835,7 +835,9 @@ func (h *hugbox) appendLibraries(cache *dynlib.Cache, binaries []string, extraLi
 		ldSoAlias = filepath.Join("/lib", ldSoAliasFn)
 	}
 
-	toBindMount, err := cache.ResolveLibraries(binaries, extraLibs, ldLibraryPath, filterFn)
+	// Search the distribution specific directories as well.
+	fallbackLibSearchPath := strings.Join(distributionDependentLibSearchPath, fmt.Sprintf("%c", filepath.ListSeparator))
+	toBindMount, err := cache.ResolveLibraries(binaries, extraLibs, ldLibraryPath, fallbackLibSearchPath, filterFn)
 	if err != nil {
 		return err
 	}