| From 7cad044b72406cbadf048da432c29afea74c3c10 Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl> |
| Date: Wed, 5 Dec 2018 22:45:02 +0100 |
| Subject: [PATCH] journald: set a limit on the number of fields |
| |
| The fix for CVE-2018-16865 is plucked from two commits that have |
| been pushed to systemd master. |
| |
| journald: set a limit on the number of fields (1k) |
| |
| We allocate a iovec entry for each field, so with many short entries, |
| our memory usage and processing time can be large, even with a relatively |
| small message size. Let's refuse overly long entries. |
| |
| CVE-2018-16865 |
| https://bugzilla.redhat.com/show_bug.cgi?id=1653861 |
| |
| What from I can see, the problem is not from an alloca, despite what the CVE |
| description says, but from the attack multiplication that comes from creating |
| many very small iovecs: (void* + size_t) for each three bytes of input message. |
| |
| Patch backported from systemd master at |
| 052c57f132f04a3cf4148f87561618da1a6908b4. |
| |
| journal-remote: set a limit on the number of fields in a message |
| |
| Existing use of E2BIG is replaced with ENOBUFS (entry too long), and E2BIG is |
| reused for the new error condition (too many fields). |
| |
| This matches the change done for systemd-journald, hence forming the second |
| part of the fix for CVE-2018-16865 |
| (https://bugzilla.redhat.com/show_bug.cgi?id=1653861). |
| |
| Patch backported from systemd master at |
| ef4d6abe7c7fab6cbff975b32e76b09feee56074. |
| with the changes applied by 7fdb237f5473cb8fc2129e57e8a0039526dcb4fd |
| removed. |
| |
| CVE: CVE-2018-16865 |
| Upstream-Status: Backport |
| Signed-off-by: Marcus Cooper <marcusc@axis.com> |
| --- |
| src/basic/journal-importer.c | 5 ++++- |
| src/basic/journal-importer.h | 3 +++ |
| src/journal-remote/journal-remote-main.c | 7 ++++++- |
| src/journal-remote/journal-remote.c | 5 ++++- |
| src/journal/journald-native.c | 5 +++++ |
| 5 files changed, 22 insertions(+), 3 deletions(-) |
| |
| diff --git a/src/basic/journal-importer.c b/src/basic/journal-importer.c |
| index ca203bbbfc..3ac55a66d9 100644 |
| --- a/src/basic/journal-importer.c |
| +++ b/src/basic/journal-importer.c |
| @@ -23,6 +23,9 @@ enum { |
| }; |
| |
| static int iovw_put(struct iovec_wrapper *iovw, void* data, size_t len) { |
| + if (iovw->count >= ENTRY_FIELD_COUNT_MAX) |
| + return -E2BIG; |
| + |
| if (!GREEDY_REALLOC(iovw->iovec, iovw->size_bytes, iovw->count + 1)) |
| return log_oom(); |
| |
| @@ -98,7 +101,7 @@ static int get_line(JournalImporter *imp, char **line, size_t *size) { |
| imp->scanned = imp->filled; |
| if (imp->scanned >= DATA_SIZE_MAX) { |
| log_error("Entry is bigger than %u bytes.", DATA_SIZE_MAX); |
| - return -E2BIG; |
| + return -ENOBUFS; |
| } |
| |
| if (imp->passive_fd) |
| diff --git a/src/basic/journal-importer.h b/src/basic/journal-importer.h |
| index f49ce734a1..c4ae45d32d 100644 |
| --- a/src/basic/journal-importer.h |
| +++ b/src/basic/journal-importer.h |
| @@ -16,6 +16,9 @@ |
| #define DATA_SIZE_MAX (1024*1024*768u) |
| #define LINE_CHUNK 8*1024u |
| |
| +/* The maximum number of fields in an entry */ |
| +#define ENTRY_FIELD_COUNT_MAX 1024 |
| + |
| struct iovec_wrapper { |
| struct iovec *iovec; |
| size_t size_bytes; |
| diff --git a/src/journal-remote/journal-remote-main.c b/src/journal-remote/journal-remote-main.c |
| index 8fda9d1499..3a01fef646 100644 |
| --- a/src/journal-remote/journal-remote-main.c |
| +++ b/src/journal-remote/journal-remote-main.c |
| @@ -212,7 +212,12 @@ static int process_http_upload( |
| break; |
| else if (r < 0) { |
| log_warning("Failed to process data for connection %p", connection); |
| - if (r == -E2BIG) |
| + if (r == -ENOBUFS) |
| + return mhd_respondf(connection, |
| + r, MHD_HTTP_PAYLOAD_TOO_LARGE, |
| + "Entry is above the maximum of %u, aborting connection %p.", |
| + DATA_SIZE_MAX, connection); |
| + else if (r == -E2BIG) |
| return mhd_respondf(connection, |
| r, MHD_HTTP_PAYLOAD_TOO_LARGE, |
| "Entry is too large, maximum is " STRINGIFY(DATA_SIZE_MAX) " bytes."); |
| diff --git a/src/journal-remote/journal-remote.c b/src/journal-remote/journal-remote.c |
| index beb75a1cb4..67e3a70c06 100644 |
| --- a/src/journal-remote/journal-remote.c |
| +++ b/src/journal-remote/journal-remote.c |
| @@ -408,7 +408,10 @@ int journal_remote_handle_raw_source( |
| log_debug("%zu active sources remaining", s->active); |
| return 0; |
| } else if (r == -E2BIG) { |
| - log_notice_errno(E2BIG, "Entry too big, skipped"); |
| + log_notice("Entry with too many fields, skipped"); |
| + return 1; |
| + } else if (r == -ENOBUFS) { |
| + log_notice("Entry too big, skipped"); |
| return 1; |
| } else if (r == -EAGAIN) { |
| return 0; |
| diff --git a/src/journal/journald-native.c b/src/journal/journald-native.c |
| index 5ff22a10af..951d092053 100644 |
| --- a/src/journal/journald-native.c |
| +++ b/src/journal/journald-native.c |
| @@ -140,6 +140,11 @@ static int server_process_entry( |
| } |
| |
| /* A property follows */ |
| + if (n > ENTRY_FIELD_COUNT_MAX) { |
| + log_debug("Received an entry that has more than " STRINGIFY(ENTRY_FIELD_COUNT_MAX) " fields, ignoring entry."); |
| + r = 1; |
| + goto finish; |
| + } |
| |
| /* n existing properties, 1 new, +1 for _TRANSPORT */ |
| if (!GREEDY_REALLOC(iovec, m, |
| -- |
| 2.11.0 |
| |