Re: [PATCH v2 08/15] fuzz: add a DISABLE_PCI op to general-fuzzer

[Darren Kenny]

On Wednesday, 2020-08-19 at 02:11:03 -04, Alexander Bulekov wrote:
> 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>

> ---
>  tests/qtest/fuzz/general_fuzz.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/tests/qtest/fuzz/general_fuzz.c b/tests/qtest/fuzz/general_fuzz.c
> index 36d41acea0..26fcd69e45 100644
> --- a/tests/qtest/fuzz/general_fuzz.c
> +++ b/tests/qtest/fuzz/general_fuzz.c
> @@ -40,6 +40,7 @@ enum cmds{
>      OP_WRITE,
>      OP_PCI_READ,
>      OP_PCI_WRITE,
> +    OP_DISABLE_PCI,
>      OP_ADD_DMA_PATTERN,
>      OP_CLEAR_DMA_PATTERNS,
>      OP_CLOCK_STEP,
> @@ -93,6 +94,7 @@ static GArray *dma_regions;
>  
>  static GArray *dma_patterns;
>  static int dma_pattern_index;
> +static bool pci_disabled = false;
>  
>  void fuzz_dma_read_cb(size_t addr, size_t len, MemoryRegion *mr, bool 
> is_write);
>  
> @@ -433,7 +435,7 @@ 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));
> @@ -463,7 +465,7 @@ 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));
> @@ -518,6 +520,11 @@ 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 (getenv("QTEST_LOG")) {
> @@ -559,6 +566,7 @@ static void general_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,
> @@ -591,6 +599,7 @@ static void general_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 */
> -- 
> 2.27.0