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206 lines
8.6 KiB
206 lines
8.6 KiB
8 months ago
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From ed028441cc2ef0ffb9771d7266d40f18910f0ae1 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
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Date: Wed, 5 Dec 2018 22:50:39 +0100
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Subject: [PATCH] journald: when processing a native message, bail more quickly
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on overbig messages
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We'd first parse all or most of the message, and only then consider if it
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is not too large. Also, when encountering a single field over the limit,
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we'd still process the preceding part of the message. Let's be stricter,
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and check size limits early, and let's refuse the whole message if it fails
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any of the size limits.
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(cherry-picked from commit 964ef920ea6735d39f856b05fd8ef451a09a6a1d)
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Related: #1664977
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---
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src/journal/journald-native.c | 65 ++++++++++++++++++++---------------
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1 file changed, 37 insertions(+), 28 deletions(-)
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diff --git a/src/journal/journald-native.c b/src/journal/journald-native.c
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index 951d092053..110ab3641c 100644
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--- a/src/journal/journald-native.c
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+++ b/src/journal/journald-native.c
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@@ -109,7 +109,7 @@ static int server_process_entry(
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int priority = LOG_INFO;
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pid_t object_pid = 0;
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const char *p;
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- int r = 0;
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+ int r = 1;
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p = buffer;
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@@ -121,8 +121,7 @@ static int server_process_entry(
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if (!e) {
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/* Trailing noise, let's ignore it, and flush what we collected */
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log_debug("Received message with trailing noise, ignoring.");
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- r = 1; /* finish processing of the message */
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- break;
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+ break; /* finish processing of the message */
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}
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if (e == p) {
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@@ -132,8 +131,7 @@ static int server_process_entry(
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}
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if (IN_SET(*p, '.', '#')) {
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- /* Ignore control commands for now, and
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- * comments too. */
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+ /* Ignore control commands for now, and comments too. */
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*remaining -= (e - p) + 1;
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p = e + 1;
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continue;
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@@ -142,7 +140,6 @@ static int server_process_entry(
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/* A property follows */
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if (n > ENTRY_FIELD_COUNT_MAX) {
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log_debug("Received an entry that has more than " STRINGIFY(ENTRY_FIELD_COUNT_MAX) " fields, ignoring entry.");
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- r = 1;
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goto finish;
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}
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@@ -152,7 +149,7 @@ static int server_process_entry(
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N_IOVEC_META_FIELDS + N_IOVEC_OBJECT_FIELDS +
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client_context_extra_fields_n_iovec(context))) {
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r = log_oom();
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- break;
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+ goto finish;
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}
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q = memchr(p, '=', e - p);
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@@ -161,6 +158,16 @@ static int server_process_entry(
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size_t l;
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l = e - p;
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+ if (l > DATA_SIZE_MAX) {
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+ log_debug("Received text block of %zu bytes is too large, ignoring entry.", l);
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+ goto finish;
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+ }
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+
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+ if (entry_size + l + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
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+ log_debug("Entry is too big (%zu bytes after processing %zu entries), ignoring entry.",
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+ entry_size + l, n + 1);
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+ goto finish;
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+ }
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/* If the field name starts with an underscore, skip the variable, since that indicates
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* a trusted field */
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@@ -178,7 +185,7 @@ static int server_process_entry(
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p = e + 1;
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continue;
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} else {
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- uint64_t l;
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+ uint64_t l, total;
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char *k;
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if (*remaining < e - p + 1 + sizeof(uint64_t) + 1) {
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@@ -187,10 +194,16 @@ static int server_process_entry(
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}
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l = unaligned_read_le64(e + 1);
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-
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if (l > DATA_SIZE_MAX) {
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- log_debug("Received binary data block of %"PRIu64" bytes is too large, ignoring.", l);
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- break;
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+ log_debug("Received binary data block of %"PRIu64" bytes is too large, ignoring entry.", l);
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+ goto finish;
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+ }
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+
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+ total = (e - p) + 1 + l;
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+ if (entry_size + total + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
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+ log_debug("Entry is too big (%"PRIu64"bytes after processing %zu fields), ignoring.",
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+ entry_size + total, n + 1);
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+ goto finish;
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}
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if ((uint64_t) *remaining < e - p + 1 + sizeof(uint64_t) + l + 1 ||
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@@ -199,7 +212,7 @@ static int server_process_entry(
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break;
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}
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- k = malloc((e - p) + 1 + l);
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+ k = malloc(total);
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if (!k) {
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log_oom();
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break;
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@@ -228,15 +241,8 @@ static int server_process_entry(
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}
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}
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- if (n <= 0) {
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- r = 1;
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+ if (n <= 0)
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goto finish;
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- }
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-
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- if (!client_context_test_priority(context, priority)) {
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- r = 0;
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- goto finish;
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- }
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tn = n++;
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iovec[tn] = IOVEC_MAKE_STRING("_TRANSPORT=journal");
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@@ -247,6 +253,11 @@ static int server_process_entry(
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goto finish;
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}
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+ r = 0; /* Success, we read the message. */
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+
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+ if (!client_context_test_priority(context, priority))
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+ goto finish;
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+
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if (message) {
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if (s->forward_to_syslog)
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server_forward_syslog(s, syslog_fixup_facility(priority), identifier, message, ucred, tv);
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@@ -318,15 +329,13 @@ void server_process_native_file(
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bool sealed;
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int r;
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- /* Data is in the passed fd, since it didn't fit in a
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- * datagram. */
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+ /* Data is in the passed fd, probably it didn't fit in a datagram. */
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assert(s);
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assert(fd >= 0);
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/* If it's a memfd, check if it is sealed. If so, we can just
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- * use map it and use it, and do not need to copy the data
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- * out. */
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+ * mmap it and use it, and do not need to copy the data out. */
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sealed = memfd_get_sealed(fd) > 0;
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if (!sealed && (!ucred || ucred->uid != 0)) {
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@@ -397,7 +406,7 @@ void server_process_native_file(
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ssize_t n;
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if (fstatvfs(fd, &vfs) < 0) {
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- log_error_errno(errno, "Failed to stat file system of passed file, ignoring: %m");
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+ log_error_errno(errno, "Failed to stat file system of passed file, not processing it: %m");
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return;
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}
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@@ -407,7 +416,7 @@ void server_process_native_file(
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* https://github.com/systemd/systemd/issues/1822
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*/
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if (vfs.f_flag & ST_MANDLOCK) {
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- log_error("Received file descriptor from file system with mandatory locking enabled, refusing.");
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+ log_error("Received file descriptor from file system with mandatory locking enabled, not processing it.");
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return;
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}
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@@ -420,13 +429,13 @@ void server_process_native_file(
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* and so is SMB. */
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r = fd_nonblock(fd, true);
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if (r < 0) {
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- log_error_errno(r, "Failed to make fd non-blocking, ignoring: %m");
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+ log_error_errno(r, "Failed to make fd non-blocking, not processing it: %m");
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return;
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}
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/* The file is not sealed, we can't map the file here, since
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* clients might then truncate it and trigger a SIGBUS for
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- * us. So let's stupidly read it */
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+ * us. So let's stupidly read it. */
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p = malloc(st.st_size);
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if (!p) {
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