libbinder: replace dup() with fcntl(F_DUPFD_CLOEXEC)
Replace calls to dup() with fcntl(F_DUPFD_CLOEXEC). The only difference
between the two is that O_CLOEXEC is set on the newly duped file
descriptor. This helps address file descriptor leaks crossing an exec()
boundary in multi-threaded processes, and potentially fixes the following
non-reproducible SELinux denials which may be occurring because of FD
leakage from netd to clatd/dnsmasq.
avc: denied { use } for comm="clatd" path="socket:[860297]" dev="sockfs"
ino=860297 scontext=u:r:clatd:s0 tcontext=u:r:untrusted_app:s0:c512,c768
tclass=fd permissive=0
avc: denied { read write } for comm="clatd" path="socket:[1414454]"
dev="sockfs" ino=1414454 scontext=u:r:clatd:s0
tcontext=u:r:system_server:s0 tclass=tcp_socket permissive=0
avc: denied { use } for comm="clatd" path="socket:[681600]" dev="sockfs"
ino=681600 scontext=u:r:clatd:s0 tcontext=u:r:priv_app:s0:c512,c768
tclass=fd permissive=0
Test: Device boots and no obvious problems
Change-Id: I9dcd9911a093f329c6f12e39d2c49ef3df651ae5
diff --git a/libs/binder/IActivityManager.cpp b/libs/binder/IActivityManager.cpp
index 898ee52..87b295a 100644
--- a/libs/binder/IActivityManager.cpp
+++ b/libs/binder/IActivityManager.cpp
@@ -14,6 +14,9 @@
* limitations under the License.
*/
+#include <unistd.h>
+#include <fcntl.h>
+
#include <binder/IActivityManager.h>
#include <binder/Parcel.h>
@@ -42,7 +45,7 @@
// Success is indicated here by a nonzero int followed by the fd;
// failure by a zero int with no data following.
if (reply.readInt32() != 0) {
- fd = dup(reply.readParcelFileDescriptor());
+ fd = fcntl(reply.readParcelFileDescriptor(), F_DUPFD_CLOEXEC, 0);
}
} else {
// An exception was thrown back; fall through to return failure