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-rw-r--r--src/journal/journal-send.c36
-rw-r--r--src/journal/journald-native.c68
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) {