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[PATCH v6 09/16] fuzz: add a crossover function to generic-fuzzer
From: |
Alexander Bulekov |
Subject: |
[PATCH v6 09/16] fuzz: add a crossover function to generic-fuzzer |
Date: |
Wed, 21 Oct 2020 17:09:15 -0400 |
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
- [PATCH v6 04/16] fuzz: Add DMA support to the generic-fuzzer, (continued)
- [PATCH v6 04/16] fuzz: Add DMA support to the generic-fuzzer, Alexander Bulekov, 2020/10/21
- [PATCH v6 01/16] memory: Add FlatView foreach function, Alexander Bulekov, 2020/10/21
- [PATCH v6 05/16] fuzz: Declare DMA Read callback function, Alexander Bulekov, 2020/10/21
- [PATCH v6 02/16] fuzz: Add generic virtual-device fuzzer, Alexander Bulekov, 2020/10/21
- [PATCH v6 03/16] fuzz: Add PCI features to the generic fuzzer, Alexander Bulekov, 2020/10/21
- [PATCH v6 07/16] fuzz: Add support for custom crossover functions, Alexander Bulekov, 2020/10/21
- [PATCH v6 06/16] fuzz: Add fuzzer callbacks to DMA-read functions, Alexander Bulekov, 2020/10/21
- [PATCH v6 08/16] fuzz: add a DISABLE_PCI op to generic-fuzzer, Alexander Bulekov, 2020/10/21
- [PATCH v6 09/16] fuzz: add a crossover function to generic-fuzzer,
Alexander Bulekov <=
- [PATCH v6 10/16] scripts/oss-fuzz: Add script to reorder a generic-fuzzer trace, Alexander Bulekov, 2020/10/21
- [PATCH v6 12/16] fuzz: Add instructions for using generic-fuzz, Alexander Bulekov, 2020/10/21
- [PATCH v6 11/16] scripts/oss-fuzz: Add crash trace minimization script, Alexander Bulekov, 2020/10/21
- [PATCH v6 13/16] fuzz: add an "opaque" to the FuzzTarget struct, Alexander Bulekov, 2020/10/21
- [PATCH v6 14/16] fuzz: add generic-fuzz configs for oss-fuzz, Alexander Bulekov, 2020/10/21
- [PATCH v6 15/16] fuzz: register predefined generic-fuzz configs, Alexander Bulekov, 2020/10/21
- [PATCH v6 16/16] scripts/oss-fuzz: remove the generic-fuzz target, Alexander Bulekov, 2020/10/21