init: service file command only opens existing files
Mixing open or create, along with attribute(MAC) and permissions(DAC)
is a security and confusion issue.
Fix an issue where fcntl F_SETFD was called to clear O_NONBLOCK, when
it should have been F_SETFL. Did not present a problem because the
current user of this feature does writes and control messages only.
Test: gTest logd-unit-tests and check dmesg for logd content.
Bug: 32450474
Bug: 33242020
Change-Id: I23cb9a9be5ddb7e8e9c58c79838bc07536e766e6
diff --git a/init/descriptors.cpp b/init/descriptors.cpp
index 429a76e..6e457cd 100644
--- a/init/descriptors.cpp
+++ b/init/descriptors.cpp
@@ -23,6 +23,7 @@
#include <unistd.h>
#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
#include <cutils/android_get_control_file.h>
#include <cutils/sockets.h>
@@ -89,14 +90,34 @@
FileInfo::FileInfo(const std::string& name, const std::string& type, uid_t uid,
gid_t gid, int perm, const std::string& context)
+ // defaults OK for uid,..., they are ignored for this class.
: DescriptorInfo(name, type, uid, gid, perm, context) {
}
-int FileInfo::Create(const std::string& context) const {
- int flags = ((type() == "r" ? O_RDONLY :
- (type() == "w" ? (O_WRONLY | O_CREAT) :
- (O_RDWR | O_CREAT))));
- return create_file(name().c_str(), flags, perm(), uid(), gid(), context.c_str());
+int FileInfo::Create(const std::string&) const {
+ int flags = (type() == "r") ? O_RDONLY :
+ (type() == "w") ? O_WRONLY :
+ O_RDWR;
+
+ // Make sure we do not block on open (eg: devices can chose to block on
+ // carrier detect). Our intention is never to delay launch of a service
+ // for such a condition. The service can perform its own blocking on
+ // carrier detect.
+ android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(name().c_str(),
+ flags | O_NONBLOCK)));
+
+ if (fd < 0) {
+ PLOG(ERROR) << "Failed to open file '" << name().c_str() << "'";
+ return -1;
+ }
+
+ // Fixup as we set O_NONBLOCK for open, the intent for fd is to block reads.
+ fcntl(fd, F_SETFL, flags);
+
+ LOG(INFO) << "Opened file '" << name().c_str() << "'"
+ << ", flags " << std::oct << flags << std::dec;
+
+ return fd.release();
}
const std::string FileInfo::key() const {