From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
To: peter.maydell@linaro.org, qemu-devel@nongnu.org
Subject: [PULL 08/13] esp: don't underflow cmdfifo in do_cmd()
Date: Mon, 12 Apr 2021 23:20:43 +0100 [thread overview]
Message-ID: <20210412222048.22818-9-mark.cave-ayland@ilande.co.uk> (raw)
In-Reply-To: <20210412222048.22818-1-mark.cave-ayland@ilande.co.uk>
If the guest tries to execute a CDB when cmdfifo is not empty before the start
of the message out phase then clearing the message out phase data will cause
cmdfifo to underflow due to cmdfifo_cdb_offset being larger than the amount of
data within.
Since this can only occur by issuing deliberately incorrect instruction
sequences, ensure that the maximum length of esp_fifo_pop_buf() is limited to
the size of the data within cmdfifo.
Buglink: https://bugs.launchpad.net/qemu/+bug/1909247
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20210407195801.685-8-mark.cave-ayland@ilande.co.uk>
---
hw/scsi/esp.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 904fa3179c..d3b105b703 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -319,13 +319,15 @@ static void do_busid_cmd(ESPState *s, uint8_t busid)
static void do_cmd(ESPState *s)
{
- uint8_t busid = fifo8_pop(&s->cmdfifo);
+ uint8_t busid = esp_fifo_pop(&s->cmdfifo);
+ int len;
s->cmdfifo_cdb_offset--;
/* Ignore extended messages for now */
if (s->cmdfifo_cdb_offset) {
- esp_fifo_pop_buf(&s->cmdfifo, NULL, s->cmdfifo_cdb_offset);
+ len = MIN(s->cmdfifo_cdb_offset, fifo8_num_used(&s->cmdfifo));
+ esp_fifo_pop_buf(&s->cmdfifo, NULL, len);
s->cmdfifo_cdb_offset = 0;
}
--
2.20.1
next prev parent reply other threads:[~2021-04-12 22:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-12 22:20 [PULL 00/13] qemu-sparc queue 20210412 Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 01/13] esp: fix setting of ESPState mig_version_id when launching QEMU with -S option Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 02/13] esp: always check current_req is not NULL before use in DMA callbacks Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 03/13] esp: rework write_response() to avoid using the FIFO for DMA transactions Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 04/13] esp: consolidate esp_cmdfifo_push() into esp_fifo_push() Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 05/13] esp: consolidate esp_cmdfifo_pop() into esp_fifo_pop() Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 06/13] esp: introduce esp_fifo_pop_buf() and use it instead of fifo8_pop_buf() Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 07/13] esp: ensure cmdfifo is not empty and current_dev is non-NULL Mark Cave-Ayland
2021-04-12 22:20 ` Mark Cave-Ayland [this message]
2021-04-12 22:20 ` [PULL 09/13] esp: don't overflow cmdfifo in get_cmd() Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 10/13] esp: don't overflow cmdfifo if TC is larger than the cmdfifo size Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 11/13] esp: don't reset async_len directly in esp_select() if cancelling request Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 12/13] esp: ensure that do_cmd is set to zero before submitting an ESP select command Mark Cave-Ayland
2021-04-12 22:20 ` [PULL 13/13] tests/qtest: add tests for am53c974 device Mark Cave-Ayland
2021-04-13 12:04 ` [PULL 00/13] qemu-sparc queue 20210412 Peter Maydell
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