From: Alexander Bulekov <alxndr@bu.edu>
To: qemu-devel@nongnu.org
Cc: Laurent Vivier <lvivier@redhat.com>,
Thomas Huth <thuth@redhat.com>, Alexander Bulekov <alxndr@bu.edu>,
f4bug@amsat.org, darren.kenny@oracle.com, bsd@redhat.com,
stefanha@redhat.com, pbonzini@redhat.com,
dimastep@yandex-team.ru
Subject: [PATCH v6 09/16] fuzz: add a crossover function to generic-fuzzer
Date: Wed, 21 Oct 2020 17:09:15 -0400 [thread overview]
Message-ID: <20201021210922.572955-10-alxndr@bu.edu> (raw)
In-Reply-To: <20201021210922.572955-1-alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
---
tests/qtest/fuzz/generic_fuzz.c | 86 +++++++++++++++++++++++++++++++++
1 file changed, 86 insertions(+)
diff --git a/tests/qtest/fuzz/generic_fuzz.c b/tests/qtest/fuzz/generic_fuzz.c
index fb8bf4a112..f739937827 100644
--- a/tests/qtest/fuzz/generic_fuzz.c
+++ b/tests/qtest/fuzz/generic_fuzz.c
@@ -804,6 +804,91 @@ static void generic_pre_fuzz(QTestState *s)
counter_shm_init();
}
+/*
+ * When libfuzzer gives us two inputs to combine, return a new input with the
+ * following structure:
+ *
+ * Input 1 (data1)
+ * SEPARATOR
+ * Clear out the DMA Patterns
+ * SEPARATOR
+ * Disable the pci_read/write instructions
+ * SEPARATOR
+ * Input 2 (data2)
+ *
+ * The idea is to collate the core behaviors of the two inputs.
+ * For example:
+ * Input 1: maps a device's BARs, sets up three DMA patterns, and triggers
+ * device functionality A
+ * Input 2: maps a device's BARs, sets up one DMA pattern, and triggers device
+ * functionality B
+ *
+ * This function attempts to produce an input that:
+ * Ouptut: maps a device's BARs, set up three DMA patterns, triggers
+ * functionality A device, replaces the DMA patterns with a single
+ * patten, and triggers device functionality B.
+ */
+static size_t generic_fuzz_crossover(const uint8_t *data1, size_t size1, const
+ uint8_t *data2, size_t size2, uint8_t *out,
+ size_t max_out_size, unsigned int seed)
+{
+ size_t copy_len = 0, size = 0;
+
+ /* Check that we have enough space for data1 and at least part of data2 */
+ if (max_out_size <= size1 + strlen(SEPARATOR) * 3 + 2) {
+ return 0;
+ }
+
+ /* Copy_Len in the first input */
+ copy_len = size1;
+ memcpy(out + size, data1, copy_len);
+ size += copy_len;
+ max_out_size -= copy_len;
+
+ /* Append a separator */
+ copy_len = strlen(SEPARATOR);
+ memcpy(out + size, SEPARATOR, copy_len);
+ size += copy_len;
+ max_out_size -= copy_len;
+
+ /* Clear out the DMA Patterns */
+ copy_len = 1;
+ if (copy_len) {
+ out[size] = OP_CLEAR_DMA_PATTERNS;
+ }
+ size += copy_len;
+ max_out_size -= copy_len;
+
+ /* Append a separator */
+ copy_len = strlen(SEPARATOR);
+ memcpy(out + size, SEPARATOR, copy_len);
+ size += copy_len;
+ max_out_size -= copy_len;
+
+ /* Disable PCI ops. Assume data1 took care of setting up PCI */
+ copy_len = 1;
+ if (copy_len) {
+ out[size] = OP_DISABLE_PCI;
+ }
+ size += copy_len;
+ max_out_size -= copy_len;
+
+ /* Append a separator */
+ copy_len = strlen(SEPARATOR);
+ memcpy(out + size, SEPARATOR, copy_len);
+ size += copy_len;
+ max_out_size -= copy_len;
+
+ /* Copy_Len over the second input */
+ copy_len = MIN(size2, max_out_size);
+ memcpy(out + size, data2, copy_len);
+ size += copy_len;
+ max_out_size -= copy_len;
+
+ return size;
+}
+
+
static GString *generic_fuzz_cmdline(FuzzTarget *t)
{
GString *cmd_line = g_string_new(TARGET_NAME);
@@ -824,6 +909,7 @@ static void register_generic_fuzz_targets(void)
.get_init_cmdline = generic_fuzz_cmdline,
.pre_fuzz = generic_pre_fuzz,
.fuzz = generic_fuzz,
+ .crossover = generic_fuzz_crossover
});
}
--
2.28.0
next prev parent reply other threads:[~2020-10-21 21:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 21:09 [PATCH v6 00/16] Add a Generic Virtual Device Fuzzer Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 01/16] memory: Add FlatView foreach function Alexander Bulekov
2020-10-22 8:09 ` Darren Kenny
2020-10-21 21:09 ` [PATCH v6 02/16] fuzz: Add generic virtual-device fuzzer Alexander Bulekov
2020-10-22 9:12 ` Darren Kenny
2020-10-21 21:09 ` [PATCH v6 03/16] fuzz: Add PCI features to the generic fuzzer Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 04/16] fuzz: Add DMA support to the generic-fuzzer Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 05/16] fuzz: Declare DMA Read callback function Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 06/16] fuzz: Add fuzzer callbacks to DMA-read functions Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 07/16] fuzz: Add support for custom crossover functions Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 08/16] fuzz: add a DISABLE_PCI op to generic-fuzzer Alexander Bulekov
2020-10-21 21:09 ` Alexander Bulekov [this message]
2020-10-21 21:09 ` [PATCH v6 10/16] scripts/oss-fuzz: Add script to reorder a generic-fuzzer trace Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 11/16] scripts/oss-fuzz: Add crash trace minimization script Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 12/16] fuzz: Add instructions for using generic-fuzz Alexander Bulekov
2020-10-21 21:09 ` [PATCH v6 13/16] fuzz: add an "opaque" to the FuzzTarget struct Alexander Bulekov
2020-10-22 9:14 ` Darren Kenny
2020-10-21 21:09 ` [PATCH v6 14/16] fuzz: add generic-fuzz configs for oss-fuzz Alexander Bulekov
2020-10-22 9:15 ` Darren Kenny
2020-10-21 21:09 ` [PATCH v6 15/16] fuzz: register predefined generic-fuzz configs Alexander Bulekov
2020-10-22 9:18 ` Darren Kenny
2020-10-21 21:09 ` [PATCH v6 16/16] scripts/oss-fuzz: remove the generic-fuzz target Alexander Bulekov
2020-10-22 9:32 ` Darren Kenny
2020-10-22 13:01 ` Alexander Bulekov
2020-10-22 13:13 ` Darren Kenny
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