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Re: [PATCH v3 08/11] esp: don't overflow cmdfifo in get_cmd()
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PATCH v3 08/11] esp: don't overflow cmdfifo in get_cmd() |
Date: |
Thu, 1 Apr 2021 10:19:36 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 |
On 4/1/21 9:49 AM, Mark Cave-Ayland wrote:
> If the guest tries to read a CDB using DMA and cmdfifo is not empty then it is
> possible to overflow cmdfifo.
>
> Since this can only occur by issuing deliberately incorrect instruction
> sequences, ensure that the maximum length of the CDB transferred to cmdfifo is
> limited to the available free space within cmdfifo.
>
> Buglink: https://bugs.launchpad.net/qemu/+bug/1909247
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
> hw/scsi/esp.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
> index 7f49522e1d..c547c60395 100644
> --- a/hw/scsi/esp.c
> +++ b/hw/scsi/esp.c
> @@ -243,6 +243,7 @@ static uint32_t get_cmd(ESPState *s, uint32_t maxlen)
> }
> if (s->dma_memory_read) {
> s->dma_memory_read(s->dma_opaque, buf, dmalen);
> + dmalen = MIN(fifo8_num_free(&s->fifo), dmalen);
Ditto, GUEST_ERRORS?
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> fifo8_push_all(&s->cmdfifo, buf, dmalen);
> } else {
> if (esp_select(s) < 0) {
>
- [PATCH v3 05/11] esp: introduce esp_fifo_pop_buf() and use it instead of fifo8_pop_buf(), (continued)
- [PATCH v3 06/11] esp: ensure cmdfifo is not empty and current_dev is non-NULL, Mark Cave-Ayland, 2021/04/01
- [PATCH v3 07/11] esp: don't underflow cmdfifo in do_cmd(), Mark Cave-Ayland, 2021/04/01
- [PATCH v3 08/11] esp: don't overflow cmdfifo in get_cmd(), Mark Cave-Ayland, 2021/04/01
- Re: [PATCH v3 08/11] esp: don't overflow cmdfifo in get_cmd(),
Philippe Mathieu-Daudé <=
- [PATCH v3 09/11] esp: don't overflow cmdfifo if TC is larger than the cmdfifo size, Mark Cave-Ayland, 2021/04/01
- [PATCH v3 10/11] esp: don't reset async_len directly in esp_select() if cancelling request, Mark Cave-Ayland, 2021/04/01
- [PATCH v3 11/11] tests/qtest: add tests for am53c974 device, Mark Cave-Ayland, 2021/04/01
- Re: [PATCH v3 00/11] esp: fix asserts/segfaults discovered by fuzzer, Alexander Bulekov, 2021/04/01