diff options
| -rw-r--r-- | src/journal/journal-send.c | 36 | ||||
| -rw-r--r-- | src/journal/journald-native.c | 68 |
2 files changed, 76 insertions, 28 deletions
diff --git a/src/journal/journal-send.c b/src/journal/journal-send.c index bb1ef66dc9..bfc404e375 100644 --- a/src/journal/journal-send.c +++ b/src/journal/journal-send.c @@ -198,7 +198,7 @@ finish: _public_ int sd_journal_sendv(const struct iovec *iov, int n) { PROTECT_ERRNO; - int fd; + int fd, r; _cleanup_close_ int buffer_fd = -1; struct iovec *w; uint64_t *l; @@ -218,6 +218,7 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) { } control; struct cmsghdr *cmsg; bool have_syslog_identifier = false; + bool seal = true; assert_return(iov, -EINVAL); assert_return(n > 0, -EINVAL); @@ -304,21 +305,36 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) { if (errno != EMSGSIZE && errno != ENOBUFS) return -errno; - /* Message doesn't fit... Let's dump the data in a temporary - * file and just pass a file descriptor of it to the other - * side. + /* Message doesn't fit... Let's dump the data in a memfd or + * temporary file and just pass a file descriptor of it to the + * other side. * - * We use /dev/shm instead of /tmp here, since we want this to - * be a tmpfs, and one that is available from early boot on - * and where unprivileged users can create files. */ - buffer_fd = open_tmpfile("/dev/shm", O_RDWR | O_CLOEXEC); - if (buffer_fd < 0) - return buffer_fd; + * For the temporary files we use /dev/shm instead of /tmp + * here, since we want this to be a tmpfs, and one that is + * available from early boot on and where unprivileged users + * can create files. */ + buffer_fd = memfd_create("journal-message", MFD_ALLOW_SEALING | MFD_CLOEXEC); + if (buffer_fd < 0) { + if (errno == ENOSYS) { + buffer_fd = open_tmpfile("/dev/shm", O_RDWR | O_CLOEXEC); + if (buffer_fd < 0) + return buffer_fd; + + seal = false; + } else + return -errno; + } n = writev(buffer_fd, w, j); if (n < 0) return -errno; + if (seal) { + r = fcntl(buffer_fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); + if (r < 0) + return -errno; + } + mh.msg_iov = NULL; mh.msg_iovlen = 0; diff --git a/src/journal/journald-native.c b/src/journal/journald-native.c index a6352022dd..6a9ae8a6ce 100644 --- a/src/journal/journald-native.c +++ b/src/journal/journald-native.c @@ -22,6 +22,7 @@ #include <unistd.h> #include <stddef.h> #include <sys/epoll.h> +#include <sys/mman.h> #include "socket-util.h" #include "path-util.h" @@ -306,17 +307,29 @@ void server_process_native_file( const char *label, size_t label_len) { struct stat st; - _cleanup_free_ void *p = NULL; - ssize_t n; + bool sealed; int r; + /* Data is in the passed fd, since it didn't fit in a + * datagram. */ + assert(s); assert(fd >= 0); - if (!ucred || ucred->uid != 0) { + /* If it's a memfd, check if it is sealed. If so, we can just + * use map it and use it, and do not need to copy the data + * out. */ + r = fcntl(fd, F_GET_SEALS); + sealed = r >= 0 && + (r & (F_SEAL_SHRINK|F_SEAL_GROW|F_SEAL_WRITE|F_SEAL_SEAL)) == (F_SEAL_SHRINK|F_SEAL_GROW|F_SEAL_WRITE|F_SEAL_SEAL); + + if (!sealed && (!ucred || ucred->uid != 0)) { _cleanup_free_ char *sl = NULL, *k = NULL; const char *e; + /* If this is not a sealed memfd, and the peer is unknown or + * unprivileged, then verify the path. */ + if (asprintf(&sl, "/proc/self/fd/%i", fd) < 0) { log_oom(); return; @@ -344,11 +357,6 @@ void server_process_native_file( } } - /* Data is in the passed file, since it didn't fit in a - * datagram. We can't map the file here, since clients might - * then truncate it and trigger a SIGBUS for us. So let's - * stupidly read it */ - if (fstat(fd, &st) < 0) { log_error("Failed to stat passed file, ignoring: %m"); return; @@ -367,17 +375,41 @@ void server_process_native_file( return; } - p = malloc(st.st_size); - if (!p) { - log_oom(); - return; - } + if (sealed) { + void *p; + size_t ps; + + /* The file is sealed, we can just map it and use it. */ - n = pread(fd, p, st.st_size, 0); - if (n < 0) - log_error("Failed to read file, ignoring: %s", strerror(-n)); - else if (n > 0) - server_process_native_message(s, p, n, ucred, tv, label, label_len); + ps = PAGE_ALIGN(st.st_size); + p = mmap(NULL, ps, PROT_READ, MAP_PRIVATE, fd, 0); + if (p == MAP_FAILED) { + log_error("Failed to map memfd, ignoring: %m"); + return; + } + + server_process_native_message(s, p, st.st_size, ucred, tv, label, label_len); + assert_se(munmap(p, ps) >= 0); + } else { + _cleanup_free_ void *p = NULL; + ssize_t n; + + /* The file is not sealed, we can't map the file here, since + * clients might then truncate it and trigger a SIGBUS for + * us. So let's stupidly read it */ + + p = malloc(st.st_size); + if (!p) { + log_oom(); + return; + } + + n = pread(fd, p, st.st_size, 0); + if (n < 0) + log_error("Failed to read file, ignoring: %s", strerror(-n)); + else if (n > 0) + server_process_native_message(s, p, n, ucred, tv, label, label_len); + } } int server_open_native_socket(Server*s) { |