# HG changeset patch # User goetz # Date 1421161792 -3600 # Tue Jan 13 16:09:52 2015 +0100 # Node ID 8a748ce0e308a8fac4baa88f4c212ca8f9055f58 # Parent 9989538b75073e6d9ad9f2510d9ef48c8ea2f141 8069590: AIX port of "8050807: Better performing performance data handling" Reviewed-by: simonis, goetz Contributed-by: matthias.baesken@sap.com, martin.doerr@sap.com diff --git a/make/aix/makefiles/xlc.make b/make/aix/makefiles/xlc.make --- a/make/aix/makefiles/xlc.make +++ b/make/aix/makefiles/xlc.make @@ -74,6 +74,12 @@ # no xlc counterpart for -fcheck-new # CFLAGS += -fcheck-new +# We need to define this on the command line if we want to use the the +# predefined format specifiers from "inttypes.h". Otherwise system headrs +# can indirectly include inttypes.h before we define __STDC_FORMAT_MACROS +# in globalDefinitions.hpp +CFLAGS += -D__STDC_FORMAT_MACROS + ARCHFLAG = -q64 CFLAGS += $(ARCHFLAG) diff --git a/src/os/aix/vm/perfMemory_aix.cpp b/src/os/aix/vm/perfMemory_aix.cpp --- a/src/os/aix/vm/perfMemory_aix.cpp +++ b/src/os/aix/vm/perfMemory_aix.cpp @@ -31,6 +31,7 @@ #include "os_aix.inline.hpp" #include "runtime/handles.inline.hpp" #include "runtime/perfMemory.hpp" +#include "services/memTracker.hpp" #include "utilities/exceptions.hpp" // put OS-includes here @@ -196,12 +197,37 @@ return pid; } +// Check if the given statbuf is considered a secure directory for +// the backing store files. Returns true if the directory is considered +// a secure location. Returns false if the statbuf is a symbolic link or +// if an error occurred. +static bool is_statbuf_secure(struct stat *statp) { + if (S_ISLNK(statp->st_mode) || !S_ISDIR(statp->st_mode)) { + // The path represents a link or some non-directory file type, + // which is not what we expected. Declare it insecure. + // + return false; + } + // We have an existing directory, check if the permissions are safe. + if ((statp->st_mode & (S_IWGRP|S_IWOTH)) != 0) { + // The directory is open for writing and could be subjected + // to a symlink or a hard link attack. Declare it insecure. + return false; + } + // See if the uid of the directory matches the effective uid of the process. + // + if (statp->st_uid != geteuid()) { + // The directory was not created by this user, declare it insecure. + return false; + } + return true; +} -// check if the given path is considered a secure directory for + +// Check if the given path is considered a secure directory for // the backing store files. Returns true if the directory exists // and is considered a secure location. Returns false if the path // is a symbolic link or if an error occurred. -// static bool is_directory_secure(const char* path) { struct stat statbuf; int result = 0; @@ -211,38 +237,276 @@ return false; } - // the path exists, now check it's mode - if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) { - // the path represents a link or some non-directory file type, - // which is not what we expected. declare it insecure. - // + // The path exists, see if it is secure. + return is_statbuf_secure(&statbuf); +} + +// (Taken over from Solaris to support the O_NOFOLLOW case on AIX.) +// Check if the given directory file descriptor is considered a secure +// directory for the backing store files. Returns true if the directory +// exists and is considered a secure location. Returns false if the path +// is a symbolic link or if an error occurred. +static bool is_dirfd_secure(int dir_fd) { + struct stat statbuf; + int result = 0; + + RESTARTABLE(::fstat(dir_fd, &statbuf), result); + if (result == OS_ERR) { return false; } - else { - // we have an existing directory, check if the permissions are safe. - // - if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) { - // the directory is open for writing and could be subjected - // to a symlnk attack. declare it insecure. - // - return false; + + // The path exists, now check its mode. + return is_statbuf_secure(&statbuf); +} + + +// Check to make sure fd1 and fd2 are referencing the same file system object. +static bool is_same_fsobject(int fd1, int fd2) { + struct stat statbuf1; + struct stat statbuf2; + int result = 0; + + RESTARTABLE(::fstat(fd1, &statbuf1), result); + if (result == OS_ERR) { + return false; + } + RESTARTABLE(::fstat(fd2, &statbuf2), result); + if (result == OS_ERR) { + return false; + } + + if ((statbuf1.st_ino == statbuf2.st_ino) && + (statbuf1.st_dev == statbuf2.st_dev)) { + return true; + } else { + return false; + } +} + +// Helper functions for open without O_NOFOLLOW which is not present on AIX 5.3/6.1. +// We use the jdk6 implementation here. +#ifndef O_NOFOLLOW +// The O_NOFOLLOW oflag doesn't exist before solaris 5.10, this is to simulate that behaviour +// was done in jdk 5/6 hotspot by Oracle this way +static int open_o_nofollow_impl(const char* path, int oflag, mode_t mode, bool use_mode) { + struct stat orig_st; + struct stat new_st; + bool create; + int error; + int fd; + + create = false; + + if (lstat(path, &orig_st) != 0) { + if (errno == ENOENT && (oflag & O_CREAT) != 0) { + // File doesn't exist, but_we want to create it, add O_EXCL flag + // to make sure no-one creates it (or a symlink) before us + // This works as we expect with symlinks, from posix man page: + // 'If O_EXCL and O_CREAT are set, and path names a symbolic + // link, open() shall fail and set errno to [EEXIST]'. + oflag |= O_EXCL; + create = true; + } else { + // File doesn't exist, and we are not creating it. + return OS_ERR; } + } else { + // Lstat success, check if existing file is a link. + if ((orig_st.st_mode & S_IFMT) == S_IFLNK) { + // File is a symlink. + errno = ELOOP; + return OS_ERR; + } + } + + if (use_mode == true) { + fd = open(path, oflag, mode); + } else { + fd = open(path, oflag); + } + + if (fd == OS_ERR) { + return fd; + } + + // Can't do inode checks on before/after if we created the file. + if (create == false) { + if (fstat(fd, &new_st) != 0) { + // Keep errno from fstat, in case close also fails. + error = errno; + ::close(fd); + errno = error; + return OS_ERR; + } + + if (orig_st.st_dev != new_st.st_dev || orig_st.st_ino != new_st.st_ino) { + // File was tampered with during race window. + ::close(fd); + errno = EEXIST; + if (PrintMiscellaneous && Verbose) { + warning("possible file tampering attempt detected when opening %s", path); + } + return OS_ERR; + } + } + + return fd; +} + +static int open_o_nofollow(const char* path, int oflag, mode_t mode) { + return open_o_nofollow_impl(path, oflag, mode, true); +} + +static int open_o_nofollow(const char* path, int oflag) { + return open_o_nofollow_impl(path, oflag, 0, false); +} +#endif + +// Open the directory of the given path and validate it. +// Return a DIR * of the open directory. +static DIR *open_directory_secure(const char* dirname) { + // Open the directory using open() so that it can be verified + // to be secure by calling is_dirfd_secure(), opendir() and then check + // to see if they are the same file system object. This method does not + // introduce a window of opportunity for the directory to be attacked that + // calling opendir() and is_directory_secure() does. + int result; + DIR *dirp = NULL; + + // No O_NOFOLLOW defined at buildtime, and it is not documented for open; + // so provide a workaround in this case. +#ifdef O_NOFOLLOW + RESTARTABLE(::open(dirname, O_RDONLY|O_NOFOLLOW), result); +#else + // workaround (jdk6 coding) + RESTARTABLE(::open_o_nofollow(dirname, O_RDONLY), result); +#endif + + if (result == OS_ERR) { + // Directory doesn't exist or is a symlink, so there is nothing to cleanup. + if (PrintMiscellaneous && Verbose) { + if (errno == ELOOP) { + warning("directory %s is a symlink and is not secure\n", dirname); + } else { + warning("could not open directory %s: %s\n", dirname, strerror(errno)); + } + } + return dirp; + } + int fd = result; + + // Determine if the open directory is secure. + if (!is_dirfd_secure(fd)) { + // The directory is not a secure directory. + os::close(fd); + return dirp; + } + + // Open the directory. + dirp = ::opendir(dirname); + if (dirp == NULL) { + // The directory doesn't exist, close fd and return. + os::close(fd); + return dirp; + } + + // Check to make sure fd and dirp are referencing the same file system object. + if (!is_same_fsobject(fd, dirp->dd_fd)) { + // The directory is not secure. + os::close(fd); + os::closedir(dirp); + dirp = NULL; + return dirp; + } + + // Close initial open now that we know directory is secure + os::close(fd); + + return dirp; +} + +// NOTE: The code below uses fchdir(), open() and unlink() because +// fdopendir(), openat() and unlinkat() are not supported on all +// versions. Once the support for fdopendir(), openat() and unlinkat() +// is available on all supported versions the code can be changed +// to use these functions. + +// Open the directory of the given path, validate it and set the +// current working directory to it. +// Return a DIR * of the open directory and the saved cwd fd. +// +static DIR *open_directory_secure_cwd(const char* dirname, int *saved_cwd_fd) { + + // Open the directory. + DIR* dirp = open_directory_secure(dirname); + if (dirp == NULL) { + // Directory doesn't exist or is insecure, so there is nothing to cleanup. + return dirp; + } + int fd = dirp->dd_fd; + + // Open a fd to the cwd and save it off. + int result; + RESTARTABLE(::open(".", O_RDONLY), result); + if (result == OS_ERR) { + *saved_cwd_fd = -1; + } else { + *saved_cwd_fd = result; + } + + // Set the current directory to dirname by using the fd of the directory. + result = fchdir(fd); + + return dirp; +} + +// Close the directory and restore the current working directory. +static void close_directory_secure_cwd(DIR* dirp, int saved_cwd_fd) { + + int result; + // If we have a saved cwd change back to it and close the fd. + if (saved_cwd_fd != -1) { + result = fchdir(saved_cwd_fd); + ::close(saved_cwd_fd); + } + + // Close the directory. + os::closedir(dirp); +} + +// Check if the given file descriptor is considered a secure. +static bool is_file_secure(int fd, const char *filename) { + + int result; + struct stat statbuf; + + // Determine if the file is secure. + RESTARTABLE(::fstat(fd, &statbuf), result); + if (result == OS_ERR) { + if (PrintMiscellaneous && Verbose) { + warning("fstat failed on %s: %s\n", filename, strerror(errno)); + } + return false; + } + if (statbuf.st_nlink > 1) { + // A file with multiple links is not expected. + if (PrintMiscellaneous && Verbose) { + warning("file %s has multiple links\n", filename); + } + return false; } return true; } - -// return the user name for the given user id +// Return the user name for the given user id. // -// the caller is expected to free the allocated memory. -// +// The caller is expected to free the allocated memory. static char* get_user_name(uid_t uid) { struct passwd pwent; - // determine the max pwbuf size from sysconf, and hardcode + // Determine the max pwbuf size from sysconf, and hardcode // a default if this not available through sysconf. - // long bufsize = sysconf(_SC_GETPW_R_SIZE_MAX); if (bufsize == -1) bufsize = 1024; @@ -344,7 +608,8 @@ strcat(usrdir_name, "/"); strcat(usrdir_name, dentry->d_name); - DIR* subdirp = os::opendir(usrdir_name); + // Open the user directory. + DIR* subdirp = open_directory_secure(usrdir_name); if (subdirp == NULL) { FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal); @@ -464,28 +729,7 @@ } } - -// remove file -// -// this method removes the file with the given file name in the -// named directory. -// -static void remove_file(const char* dirname, const char* filename) { - - size_t nbytes = strlen(dirname) + strlen(filename) + 2; - char* path = NEW_C_HEAP_ARRAY(char, nbytes, mtInternal); - - strcpy(path, dirname); - strcat(path, "/"); - strcat(path, filename); - - remove_file(path); - - FREE_C_HEAP_ARRAY(char, path, mtInternal); -} - - -// cleanup stale shared memory resources +// Cleanup stale shared memory resources // // This method attempts to remove all stale shared memory files in // the named user temporary directory. It scans the named directory @@ -493,32 +737,26 @@ // process id is extracted from the file name and a test is run to // determine if the process is alive. If the process is not alive, // any stale file resources are removed. -// static void cleanup_sharedmem_resources(const char* dirname) { - // open the user temp directory - DIR* dirp = os::opendir(dirname); - + int saved_cwd_fd; + // Open the directory. + DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd); if (dirp == NULL) { - // directory doesn't exist, so there is nothing to cleanup + // Directory doesn't exist or is insecure, so there is nothing to cleanup. return; } - if (!is_directory_secure(dirname)) { - // the directory is not a secure directory - return; - } - - // for each entry in the directory that matches the expected file + // For each entry in the directory that matches the expected file // name pattern, determine if the file resources are stale and if // so, remove the file resources. Note, instrumented HotSpot processes // for this user may start and/or terminate during this search and // remove or create new files in this directory. The behavior of this // loop under these conditions is dependent upon the implementation of // opendir/readdir. - // struct dirent* entry; char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal); + errno = 0; while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) { @@ -528,56 +766,55 @@ if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { - // attempt to remove all unexpected files, except "." and ".." - remove_file(dirname, entry->d_name); + // Attempt to remove all unexpected files, except "." and "..". + unlink(entry->d_name); } errno = 0; continue; } - // we now have a file name that converts to a valid integer + // We now have a file name that converts to a valid integer // that could represent a process id . if this process id // matches the current process id or the process is not running, // then remove the stale file resources. // - // process liveness is detected by sending signal number 0 to + // Process liveness is detected by sending signal number 0 to // the process id (see kill(2)). if kill determines that the // process does not exist, then the file resources are removed. // if kill determines that that we don't have permission to // signal the process, then the file resources are assumed to // be stale and are removed because the resources for such a // process should be in a different user specific directory. - // if ((pid == os::current_process_id()) || (kill(pid, 0) == OS_ERR && (errno == ESRCH || errno == EPERM))) { - remove_file(dirname, entry->d_name); + unlink(entry->d_name); } errno = 0; } - os::closedir(dirp); + + // Close the directory and reset the current working directory. + close_directory_secure_cwd(dirp, saved_cwd_fd); + FREE_C_HEAP_ARRAY(char, dbuf, mtInternal); } -// make the user specific temporary directory. Returns true if +// Make the user specific temporary directory. Returns true if // the directory exists and is secure upon return. Returns false // if the directory exists but is either a symlink, is otherwise // insecure, or if an error occurred. -// static bool make_user_tmp_dir(const char* dirname) { - // create the directory with 0755 permissions. note that the directory + // Create the directory with 0755 permissions. note that the directory // will be owned by euid::egid, which may not be the same as uid::gid. - // if (mkdir(dirname, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) == OS_ERR) { if (errno == EEXIST) { // The directory already exists and was probably created by another // JVM instance. However, this could also be the result of a // deliberate symlink. Verify that the existing directory is safe. - // if (!is_directory_secure(dirname)) { - // directory is not secure + // Directory is not secure. if (PrintMiscellaneous && Verbose) { warning("%s directory is insecure\n", dirname); } @@ -613,19 +850,63 @@ return -1; } + int saved_cwd_fd; + // Open the directory and set the current working directory to it. + DIR* dirp = open_directory_secure_cwd(dirname, &saved_cwd_fd); + if (dirp == NULL) { + // Directory doesn't exist or is insecure, so cannot create shared + // memory file. + return -1; + } + + // Open the filename in the current directory. + // Cannot use O_TRUNC here; truncation of an existing file has to happen + // after the is_file_secure() check below. int result; - RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_TRUNC, S_IREAD|S_IWRITE), result); + // No O_NOFOLLOW defined at buildtime, and it is not documented for open; + // so provide a workaround in this case. +#ifdef O_NOFOLLOW + RESTARTABLE(::open(filename, O_RDWR|O_CREAT|O_NOFOLLOW, S_IREAD|S_IWRITE), result); +#else + // workaround function (jdk6 code) + RESTARTABLE(::open_o_nofollow(filename, O_RDWR|O_CREAT, S_IREAD|S_IWRITE), result); +#endif + if (result == OS_ERR) { if (PrintMiscellaneous && Verbose) { - warning("could not create file %s: %s\n", filename, strerror(errno)); + if (errno == ELOOP) { + warning("file %s is a symlink and is not secure\n", filename); + } else { + warning("could not create file %s: %s\n", filename, strerror(errno)); + } } + // Close the directory and reset the current working directory. + close_directory_secure_cwd(dirp, saved_cwd_fd); + return -1; } + // Close the directory and reset the current working directory. + close_directory_secure_cwd(dirp, saved_cwd_fd); // save the file descriptor int fd = result; + // Check to see if the file is secure. + if (!is_file_secure(fd, filename)) { + ::close(fd); + return -1; + } + + // Truncate the file to get rid of any existing data. + RESTARTABLE(::ftruncate(fd, (off_t)0), result); + if (result == OS_ERR) { + if (PrintMiscellaneous && Verbose) { + warning("could not truncate shared memory file: %s\n", strerror(errno)); + } + ::close(fd); + return -1; + } // set the file size RESTARTABLE(::ftruncate(fd, (off_t)size), result); if (result == OS_ERR) { @@ -647,7 +928,14 @@ // open the file int result; + // No O_NOFOLLOW defined at buildtime, and it is not documented for open; + // so provide a workaround in this case +#ifdef O_NOFOLLOW RESTARTABLE(::open(filename, oflags), result); +#else + RESTARTABLE(::open_o_nofollow(filename, oflags), result); +#endif + if (result == OS_ERR) { if (errno == ENOENT) { THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), @@ -661,8 +949,15 @@ THROW_MSG_0(vmSymbols::java_io_IOException(), strerror(errno)); } } + int fd = result; - return result; + // Check to see if the file is secure. + if (!is_file_secure(fd, filename)) { + ::close(fd); + return -1; + } + + return fd; } // create a named shared memory region. returns the address of the @@ -694,13 +989,21 @@ char* dirname = get_user_tmp_dir(user_name); char* filename = get_sharedmem_filename(dirname, vmid); + // Get the short filename. + char* short_filename = strrchr(filename, '/'); + if (short_filename == NULL) { + short_filename = filename; + } else { + short_filename++; + } + // cleanup any stale shared memory files cleanup_sharedmem_resources(dirname); assert(((size > 0) && (size % os::vm_page_size() == 0)), "unexpected PerfMemory region size"); - fd = create_sharedmem_resources(dirname, filename, size); + fd = create_sharedmem_resources(dirname, short_filename, size); FREE_C_HEAP_ARRAY(char, user_name, mtInternal); FREE_C_HEAP_ARRAY(char, dirname, mtInternal); @@ -732,6 +1035,9 @@ // clear the shared memory region (void)::memset((void*) mapAddress, 0, size); + // It does not go through os api, the operation has to record from here. + MemTracker::record_virtual_memory_reserve((address)mapAddress, size, CURRENT_PC, mtInternal); + return mapAddress; } @@ -806,7 +1112,7 @@ char* mapAddress; int result; int fd; - size_t size; + size_t size = 0; const char* luser = NULL; int mmap_prot; @@ -818,12 +1124,18 @@ // constructs for the file and the shared memory mapping. if (mode == PerfMemory::PERF_MODE_RO) { mmap_prot = PROT_READ; + + // No O_NOFOLLOW defined at buildtime, and it is not documented for open. +#ifdef O_NOFOLLOW + file_flags = O_RDONLY | O_NOFOLLOW; +#else file_flags = O_RDONLY; +#endif } else if (mode == PerfMemory::PERF_MODE_RW) { #ifdef LATER mmap_prot = PROT_READ | PROT_WRITE; - file_flags = O_RDWR; + file_flags = O_RDWR | O_NOFOLLOW; #else THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "Unsupported access mode"); @@ -853,6 +1165,9 @@ // if (!is_directory_secure(dirname)) { FREE_C_HEAP_ARRAY(char, dirname, mtInternal); + if (luser != user) { + FREE_C_HEAP_ARRAY(char, luser, mtInternal); + } THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "Process not found"); } @@ -897,6 +1212,9 @@ "Could not map PerfMemory"); } + // It does not go through os api, the operation has to record from here. + MemTracker::record_virtual_memory_reserve((address)mapAddress, size, CURRENT_PC, mtInternal); + *addr = mapAddress; *sizep = size;