[PULL 16/31] fuzz: add a DISABLE_PCI op to generic-fuzzer

[Thomas Huth <thuth@redhat.com>]

From: Alexander Bulekov <alxndr@bu.edu>

This new operation is used in the next commit, which concatenates two
fuzzer-generated inputs. With this operation, we can prevent the second
input from clobbering the PCI configuration performed by the first.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201023150746.107063-9-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 tests/qtest/fuzz/generic_fuzz.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/tests/qtest/fuzz/generic_fuzz.c b/tests/qtest/fuzz/generic_fuzz.c
index 62a94de9dd..6ec20464bd 100644
--- a/tests/qtest/fuzz/generic_fuzz.c
+++ b/tests/qtest/fuzz/generic_fuzz.c
@@ -39,6 +39,7 @@ enum cmds {
     OP_WRITE,
     OP_PCI_READ,
     OP_PCI_WRITE,
+    OP_DISABLE_PCI,
     OP_ADD_DMA_PATTERN,
     OP_CLEAR_DMA_PATTERNS,
     OP_CLOCK_STEP,
@@ -116,6 +117,7 @@ static GArray *dma_regions;
 
 static GArray *dma_patterns;
 static int dma_pattern_index;
+static bool pci_disabled;
 
 /*
  * Allocate a block of memory and populate it with a pattern.
@@ -484,7 +486,7 @@ static void op_pci_read(QTestState *s, const unsigned char * data, size_t len)
         uint8_t base;
         uint8_t offset;
     } a;
-    if (len < sizeof(a) || fuzzable_pci_devices->len == 0) {
+    if (len < sizeof(a) || fuzzable_pci_devices->len == 0 || pci_disabled) {
         return;
     }
     memcpy(&a, data, sizeof(a));
@@ -514,7 +516,7 @@ static void op_pci_write(QTestState *s, const unsigned char * data, size_t len)
         uint8_t offset;
         uint32_t value;
     } a;
-    if (len < sizeof(a) || fuzzable_pci_devices->len == 0) {
+    if (len < sizeof(a) || fuzzable_pci_devices->len == 0 || pci_disabled) {
         return;
     }
     memcpy(&a, data, sizeof(a));
@@ -569,6 +571,11 @@ static void op_clock_step(QTestState *s, const unsigned char *data, size_t len)
     qtest_clock_step_next(s);
 }
 
+static void op_disable_pci(QTestState *s, const unsigned char *data, size_t len)
+{
+    pci_disabled = true;
+}
+
 static void handle_timeout(int sig)
 {
     if (qtest_log_enabled) {
@@ -624,6 +631,7 @@ static void generic_fuzz(QTestState *s, const unsigned char *Data, size_t Size)
         [OP_WRITE]              = op_write,
         [OP_PCI_READ]           = op_pci_read,
         [OP_PCI_WRITE]          = op_pci_write,
+        [OP_DISABLE_PCI]        = op_disable_pci,
         [OP_ADD_DMA_PATTERN]    = op_add_dma_pattern,
         [OP_CLEAR_DMA_PATTERNS] = op_clear_dma_patterns,
         [OP_CLOCK_STEP]         = op_clock_step,
@@ -656,6 +664,7 @@ static void generic_fuzz(QTestState *s, const unsigned char *Data, size_t Size)
         }
 
         op_clear_dma_patterns(s, NULL, 0);
+        pci_disabled = false;
 
         while (cmd && Size) {
             /* Get the length until the next command or end of input */
-- 
2.18.2