Loading core/jni/com_android_internal_os_Zygote.cpp +5 −1 Original line number Diff line number Diff line Loading @@ -454,6 +454,10 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra SetForkLoad(true); #endif // Close any logging related FDs before we start evaluating the list of // file descriptors. __android_log_close(); // If this is the first fork for this zygote, create the open FD table. // If it isn't, we just need to check whether the list of open files has // changed (and it shouldn't in the normal case). Loading @@ -477,7 +481,7 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra // Re-open all remaining open file descriptors so that they aren't shared // with the zygote across a fork. if (!gOpenFdTable->Reopen()) { if (!gOpenFdTable->ReopenOrDetach()) { RuntimeAbort(env, __LINE__, "Unable to reopen whitelisted descriptors."); } Loading core/jni/fd_utils-inl.h +102 −18 Original line number Diff line number Diff line Loading @@ -25,22 +25,32 @@ #include <grp.h> #include <inttypes.h> #include <stdlib.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/un.h> #include <unistd.h> #include <cutils/log.h> #include "JNIHelp.h" #include "ScopedPrimitiveArray.h" // Whitelist of open paths that the zygote is allowed to keep open // that will be recreated across forks. In addition to files here, // all files ending with ".jar" under /system/framework" are // whitelisted. See FileDescriptorInfo::IsWhitelisted for the // canonical definition. // Whitelist of open paths that the zygote is allowed to keep open. // // In addition to the paths listed here, all files ending with // ".jar" under /system/framework" are whitelisted. See // FileDescriptorInfo::IsWhitelisted for the canonical definition. // // If the whitelisted path is associated with a regular file or a // character device, the file is reopened after a fork with the same // offset and mode. If the whilelisted path is associated with a // AF_UNIX socket, the socket will refer to /dev/null after each // fork, and all operations on it will fail. static const char* kPathWhitelist[] = { "/dev/null", "/dev/pmsg0", "/dev/socket/zygote", "/dev/socket/zygote_secondary", "/system/etc/event-log-tags", "/sys/kernel/debug/tracing/trace_marker", "/system/framework/framework-res.apk", Loading @@ -66,9 +76,17 @@ class FileDescriptorInfo { return NULL; } // Ignore (don't reopen or fail on) socket fds for now. if (S_ISSOCK(f_stat.st_mode)) { ALOGW("Unsupported socket FD: %d, ignoring.", fd); std::string socket_name; if (!GetSocketName(fd, &socket_name)) { return NULL; } if (!IsWhitelisted(socket_name)) { ALOGE("Socket name not whitelisted : %s (fd=%d)", socket_name.c_str(), fd); return NULL; } return new FileDescriptorInfo(fd); } Loading Loading @@ -147,10 +165,9 @@ class FileDescriptorInfo { return f_stat.st_ino == stat.st_ino && f_stat.st_dev == stat.st_dev; } bool Reopen() const { // Always skip over socket FDs for now. bool ReopenOrDetach() const { if (is_sock) { return true; return DetachSocket(); } // NOTE: This might happen if the file was unlinked after being opened. Loading Loading @@ -187,9 +204,7 @@ class FileDescriptorInfo { return false; } if (close(new_fd) == -1) { ALOGW("Failed close(%d) : %s", new_fd, strerror(errno)); } close(new_fd); return true; } Loading Loading @@ -265,6 +280,74 @@ class FileDescriptorInfo { return true; } // Returns the locally-bound name of the socket |fd|. Returns true // iff. all of the following hold : // // - the socket's sa_family is AF_UNIX. // - the length of the path is greater than zero (i.e, not an unnamed socket). // - the first byte of the path isn't zero (i.e, not a socket with an abstract // address). static bool GetSocketName(const int fd, std::string* result) { sockaddr_storage ss; sockaddr* addr = reinterpret_cast<sockaddr*>(&ss); socklen_t addr_len = sizeof(ss); if (TEMP_FAILURE_RETRY(getsockname(fd, addr, &addr_len)) == -1) { ALOGE("Failed getsockname(%d) : %s", fd, strerror(errno)); return false; } if (addr->sa_family != AF_UNIX) { ALOGE("Unsupported socket (fd=%d) with family %d", fd, addr->sa_family); return false; } const sockaddr_un* unix_addr = reinterpret_cast<const sockaddr_un*>(&ss); size_t path_len = addr_len - offsetof(struct sockaddr_un, sun_path); // This is an unnamed local socket, we do not accept it. if (path_len == 0) { ALOGE("Unsupported AF_UNIX socket (fd=%d) with empty path.", fd); return false; } // This is a local socket with an abstract address, we do not accept it. if (unix_addr->sun_path[0] == '\0') { ALOGE("Unsupported AF_UNIX socket (fd=%d) with abstract address.", fd); return false; } // If we're here, sun_path must refer to a null terminated filesystem // pathname (man 7 unix). Remove the terminator before assigning it to an // std::string. if (unix_addr->sun_path[path_len - 1] == '\0') { --path_len; } result->assign(unix_addr->sun_path, path_len); return true; } bool DetachSocket() const { const int dev_null_fd = open("/dev/null", O_RDWR); if (dev_null_fd < 0) { ALOGE("Failed to open /dev/null : %s", strerror(errno)); return false; } if (dup2(dev_null_fd, fd) == -1) { ALOGE("Failed dup2 on socket descriptor %d : %s", fd, strerror(errno)); return false; } if (close(dev_null_fd) == -1) { ALOGE("Failed close(%d) : %s", dev_null_fd, strerror(errno)); return false; } return true; } DISALLOW_COPY_AND_ASSIGN(FileDescriptorInfo); }; Loading Loading @@ -338,12 +421,13 @@ class FileDescriptorTable { } // Reopens all file descriptors that are contained in the table. Returns true // if all descriptors were re-opened, and false if an error occurred. bool Reopen() { // if all descriptors were successfully re-opened or detached, and false if an // error occurred. bool ReopenOrDetach() { std::unordered_map<int, FileDescriptorInfo*>::const_iterator it; for (it = open_fd_map_.begin(); it != open_fd_map_.end(); ++it) { const FileDescriptorInfo* info = it->second; if (info == NULL || !info->Reopen()) { if (info == NULL || !info->ReopenOrDetach()) { return false; } } Loading Loading @@ -374,7 +458,7 @@ class FileDescriptorTable { // // TODO(narayan): This will be an error in a future android release. // error = true; ALOGW("Zygote closed file descriptor %d.", it->first); // ALOGW("Zygote closed file descriptor %d.", it->first); open_fd_map_.erase(it); } else { // The entry from the file descriptor table is still open. Restat Loading Loading @@ -405,7 +489,7 @@ class FileDescriptorTable { // // TODO(narayan): This will be an error in a future android release. // error = true; ALOGW("Zygote opened %zd new file descriptor(s).", open_fds.size()); // ALOGW("Zygote opened %zd new file descriptor(s).", open_fds.size()); // TODO(narayan): This code will be removed in a future android release. std::set<int>::const_iterator it; Loading Loading
core/jni/com_android_internal_os_Zygote.cpp +5 −1 Original line number Diff line number Diff line Loading @@ -454,6 +454,10 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra SetForkLoad(true); #endif // Close any logging related FDs before we start evaluating the list of // file descriptors. __android_log_close(); // If this is the first fork for this zygote, create the open FD table. // If it isn't, we just need to check whether the list of open files has // changed (and it shouldn't in the normal case). Loading @@ -477,7 +481,7 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra // Re-open all remaining open file descriptors so that they aren't shared // with the zygote across a fork. if (!gOpenFdTable->Reopen()) { if (!gOpenFdTable->ReopenOrDetach()) { RuntimeAbort(env, __LINE__, "Unable to reopen whitelisted descriptors."); } Loading
core/jni/fd_utils-inl.h +102 −18 Original line number Diff line number Diff line Loading @@ -25,22 +25,32 @@ #include <grp.h> #include <inttypes.h> #include <stdlib.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/un.h> #include <unistd.h> #include <cutils/log.h> #include "JNIHelp.h" #include "ScopedPrimitiveArray.h" // Whitelist of open paths that the zygote is allowed to keep open // that will be recreated across forks. In addition to files here, // all files ending with ".jar" under /system/framework" are // whitelisted. See FileDescriptorInfo::IsWhitelisted for the // canonical definition. // Whitelist of open paths that the zygote is allowed to keep open. // // In addition to the paths listed here, all files ending with // ".jar" under /system/framework" are whitelisted. See // FileDescriptorInfo::IsWhitelisted for the canonical definition. // // If the whitelisted path is associated with a regular file or a // character device, the file is reopened after a fork with the same // offset and mode. If the whilelisted path is associated with a // AF_UNIX socket, the socket will refer to /dev/null after each // fork, and all operations on it will fail. static const char* kPathWhitelist[] = { "/dev/null", "/dev/pmsg0", "/dev/socket/zygote", "/dev/socket/zygote_secondary", "/system/etc/event-log-tags", "/sys/kernel/debug/tracing/trace_marker", "/system/framework/framework-res.apk", Loading @@ -66,9 +76,17 @@ class FileDescriptorInfo { return NULL; } // Ignore (don't reopen or fail on) socket fds for now. if (S_ISSOCK(f_stat.st_mode)) { ALOGW("Unsupported socket FD: %d, ignoring.", fd); std::string socket_name; if (!GetSocketName(fd, &socket_name)) { return NULL; } if (!IsWhitelisted(socket_name)) { ALOGE("Socket name not whitelisted : %s (fd=%d)", socket_name.c_str(), fd); return NULL; } return new FileDescriptorInfo(fd); } Loading Loading @@ -147,10 +165,9 @@ class FileDescriptorInfo { return f_stat.st_ino == stat.st_ino && f_stat.st_dev == stat.st_dev; } bool Reopen() const { // Always skip over socket FDs for now. bool ReopenOrDetach() const { if (is_sock) { return true; return DetachSocket(); } // NOTE: This might happen if the file was unlinked after being opened. Loading Loading @@ -187,9 +204,7 @@ class FileDescriptorInfo { return false; } if (close(new_fd) == -1) { ALOGW("Failed close(%d) : %s", new_fd, strerror(errno)); } close(new_fd); return true; } Loading Loading @@ -265,6 +280,74 @@ class FileDescriptorInfo { return true; } // Returns the locally-bound name of the socket |fd|. Returns true // iff. all of the following hold : // // - the socket's sa_family is AF_UNIX. // - the length of the path is greater than zero (i.e, not an unnamed socket). // - the first byte of the path isn't zero (i.e, not a socket with an abstract // address). static bool GetSocketName(const int fd, std::string* result) { sockaddr_storage ss; sockaddr* addr = reinterpret_cast<sockaddr*>(&ss); socklen_t addr_len = sizeof(ss); if (TEMP_FAILURE_RETRY(getsockname(fd, addr, &addr_len)) == -1) { ALOGE("Failed getsockname(%d) : %s", fd, strerror(errno)); return false; } if (addr->sa_family != AF_UNIX) { ALOGE("Unsupported socket (fd=%d) with family %d", fd, addr->sa_family); return false; } const sockaddr_un* unix_addr = reinterpret_cast<const sockaddr_un*>(&ss); size_t path_len = addr_len - offsetof(struct sockaddr_un, sun_path); // This is an unnamed local socket, we do not accept it. if (path_len == 0) { ALOGE("Unsupported AF_UNIX socket (fd=%d) with empty path.", fd); return false; } // This is a local socket with an abstract address, we do not accept it. if (unix_addr->sun_path[0] == '\0') { ALOGE("Unsupported AF_UNIX socket (fd=%d) with abstract address.", fd); return false; } // If we're here, sun_path must refer to a null terminated filesystem // pathname (man 7 unix). Remove the terminator before assigning it to an // std::string. if (unix_addr->sun_path[path_len - 1] == '\0') { --path_len; } result->assign(unix_addr->sun_path, path_len); return true; } bool DetachSocket() const { const int dev_null_fd = open("/dev/null", O_RDWR); if (dev_null_fd < 0) { ALOGE("Failed to open /dev/null : %s", strerror(errno)); return false; } if (dup2(dev_null_fd, fd) == -1) { ALOGE("Failed dup2 on socket descriptor %d : %s", fd, strerror(errno)); return false; } if (close(dev_null_fd) == -1) { ALOGE("Failed close(%d) : %s", dev_null_fd, strerror(errno)); return false; } return true; } DISALLOW_COPY_AND_ASSIGN(FileDescriptorInfo); }; Loading Loading @@ -338,12 +421,13 @@ class FileDescriptorTable { } // Reopens all file descriptors that are contained in the table. Returns true // if all descriptors were re-opened, and false if an error occurred. bool Reopen() { // if all descriptors were successfully re-opened or detached, and false if an // error occurred. bool ReopenOrDetach() { std::unordered_map<int, FileDescriptorInfo*>::const_iterator it; for (it = open_fd_map_.begin(); it != open_fd_map_.end(); ++it) { const FileDescriptorInfo* info = it->second; if (info == NULL || !info->Reopen()) { if (info == NULL || !info->ReopenOrDetach()) { return false; } } Loading Loading @@ -374,7 +458,7 @@ class FileDescriptorTable { // // TODO(narayan): This will be an error in a future android release. // error = true; ALOGW("Zygote closed file descriptor %d.", it->first); // ALOGW("Zygote closed file descriptor %d.", it->first); open_fd_map_.erase(it); } else { // The entry from the file descriptor table is still open. Restat Loading Loading @@ -405,7 +489,7 @@ class FileDescriptorTable { // // TODO(narayan): This will be an error in a future android release. // error = true; ALOGW("Zygote opened %zd new file descriptor(s).", open_fds.size()); // ALOGW("Zygote opened %zd new file descriptor(s).", open_fds.size()); // TODO(narayan): This code will be removed in a future android release. std::set<int>::const_iterator it; Loading