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52 lines
2.1 KiB
52 lines
2.1 KiB
From 9dbac61cf123a57c1f39a2f134389f1a5877dc29 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: Thu, 3 Jan 2019 16:09:05 +0100 |
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Subject: [PATCH] journald: set a limit on the number of fields (1k) |
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We allocate a iovec entry for each field, so with many short entries, |
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our memory usage and processing time can be large, even with a relatively |
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small message size. Let's refuse overly long entries. |
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CVE-2018-16865 |
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https://bugzilla.redhat.com/show_bug.cgi?id=1653861 |
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What from I can see, the problem is not from an alloca, despite what the CVE |
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description says, but from the attack multiplication that comes from creating |
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many very small iovecs: (void* + size_t) for each three bytes of input |
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message. |
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Resolves: #1657792 |
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--- |
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src/journal/journal-file.h | 3 +++ |
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src/journal/journald-native.c | 4 ++++ |
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2 files changed, 7 insertions(+) |
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diff --git a/src/journal/journal-file.h b/src/journal/journal-file.h |
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index dd8ef52d2a..37749c4459 100644 |
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--- a/src/journal/journal-file.h |
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+++ b/src/journal/journal-file.h |
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@@ -158,6 +158,9 @@ int journal_file_open_reliably( |
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* files without adding too many zeros. */ |
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#define OFSfmt "%06"PRIx64 |
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+/* The maximum number of fields in an entry */ |
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+#define ENTRY_FIELD_COUNT_MAX 1024 |
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+ |
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static inline bool VALID_REALTIME(uint64_t u) { |
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/* This considers timestamps until the year 3112 valid. That should be plenty room... */ |
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return u > 0 && u < (1ULL << 55); |
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diff --git a/src/journal/journald-native.c b/src/journal/journald-native.c |
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index cf3349393f..0c451274f7 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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@@ -134,6 +134,10 @@ void server_process_native_message( |
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} |
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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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+ goto finish; |
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+ } |
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/* n existing properties, 1 new, +1 for _TRANSPORT */ |
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if (!GREEDY_REALLOC(iovec, m, n + 2 + N_IOVEC_META_FIELDS + N_IOVEC_OBJECT_FIELDS)) {
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