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From 242273e1afd456e86ebc48d7d601cb28297f8efb 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: Tue, 30 Oct 2018 09:02:26 +0100
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Subject: [PATCH] fuzz-compress: add fuzzer for compression and decompression
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(cherry picked from commit 029427043b2e0523a21f54374f872b23cf744350)
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Resolves: #1843871
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---
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 src/fuzz/fuzz-compress.c | 80 ++++++++++++++++++++++++++++++++++++++++
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 src/fuzz/meson.build     |  7 +++-
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 2 files changed, 86 insertions(+), 1 deletion(-)
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 create mode 100644 src/fuzz/fuzz-compress.c
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diff --git a/src/fuzz/fuzz-compress.c b/src/fuzz/fuzz-compress.c
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new file mode 100644
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index 0000000000..9c5dfc92c0
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--- /dev/null
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+++ b/src/fuzz/fuzz-compress.c
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@@ -0,0 +1,80 @@
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+/* SPDX-License-Identifier: LGPL-2.1+ */
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+
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+#include <errno.h>
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+
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+#include "alloc-util.h"
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+#include "compress.h"
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+#include "fuzz.h"
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+
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+static int compress(int alg,
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+                    const void *src, uint64_t src_size,
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+                    void *dst, size_t dst_alloc_size, size_t *dst_size) {
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+
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+        if (alg == OBJECT_COMPRESSED_LZ4)
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+                return compress_blob_lz4(src, src_size, dst, dst_alloc_size, dst_size);
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+        if (alg == OBJECT_COMPRESSED_XZ)
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+                return compress_blob_xz(src, src_size, dst, dst_alloc_size, dst_size);
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+        return -EOPNOTSUPP;
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+}
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+
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+typedef struct header {
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+        uint32_t alg:2; /* We have only two compression algorithms so far, but we might add
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+                         * more in the future. Let's make this a bit wider so our fuzzer
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+                         * cases remain stable in the future. */
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+        uint32_t sw_len;
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+        uint32_t sw_alloc;
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+        uint32_t reserved[3]; /* Extra space to keep fuzz cases stable in case we need to
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+                               * add stuff in the future. */
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+        uint8_t data[];
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+} header;
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+
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+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
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+        _cleanup_free_ void *buf = NULL, *buf2 = NULL;
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+        int r;
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+
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+        if (size < offsetof(header, data) + 1)
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+                return 0;
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+
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+        const header *h = (struct header*) data;
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+        const size_t data_len = size - offsetof(header, data);
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+
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+        int alg = h->alg;
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+
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+        /* We don't want to fill the logs with messages about parse errors.
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+         * Disable most logging if not running standalone */
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+        if (!getenv("SYSTEMD_LOG_LEVEL"))
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+                log_set_max_level(LOG_CRIT);
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+
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+        log_info("Using compression %s, data size=%zu",
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+                 object_compressed_to_string(alg) ?: "(none)",
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+                 data_len);
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+
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+        buf = malloc(MAX(size, 128u)); /* Make the buffer a bit larger for very small data */
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+        if (!buf) {
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+                log_oom();
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+                return 0;
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+        }
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+
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+        size_t csize;
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+        r = compress(alg, h->data, data_len, buf, size, &csize);
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+        if (r < 0) {
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+                log_error_errno(r, "Compression failed: %m");
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+                return 0;
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+        }
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+
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+        log_debug("Compressed %zu bytes to → %zu bytes", data_len, csize);
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+
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+        size_t sw_alloc = MAX(h->sw_alloc, 1u);
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+        buf2 = malloc(sw_alloc);
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+        if (!buf) {
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+                log_oom();
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+                return 0;
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+        }
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+
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+        size_t sw_len = MIN(data_len - 1, h->sw_len);
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+
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+        r = decompress_startswith(alg, buf, csize, &buf2, &sw_alloc, h->data, sw_len, h->data[sw_len]);
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+        assert_se(r > 0);
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+
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+        return 0;
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+}
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diff --git a/src/fuzz/meson.build b/src/fuzz/meson.build
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index 5315d2771c..b8d5979d3c 100644
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--- a/src/fuzz/meson.build
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+++ b/src/fuzz/meson.build
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@@ -73,8 +73,13 @@ fuzzers += [
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          [libsystemd_journal_remote,
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           libshared],
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          []],
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+
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         [['src/fuzz/fuzz-fido-id-desc.c',
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           'src/udev/fido_id/fido_id_desc.c'],
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          [],
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-         []]
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+         []],
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+
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+        [['src/fuzz/fuzz-compress.c'],
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+         [libshared],
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+         []],
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 ]