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From: Eden Mikitas <e.mikitas@gmail.com>
To: peter.maydell@linaro.org
Cc: qemu-trivial@nongnu.org, alistair@alistair23.me,
	qemu-devel@nongnu.org, jcd@tribudubois.net, qemu-arm@nongnu.org,
	peter.chubb@nicta.com.au, e.mikitas@gmail.com
Subject: [PATCH 1/2] hw/ssi/imx_spi: changed while statement to prevent underflow
Date: Fri, 22 May 2020 14:50:35 +0300	[thread overview]
Message-ID: <20200522115036.31516-2-e.mikitas@gmail.com> (raw)
In-Reply-To: <20200522115036.31516-1-e.mikitas@gmail.com>

The while statement in question only checked if tx_burst is not 0.
tx_burst is a signed int, which is assigned the value put by the
guest driver in ECSPI_CONREG. The burst length can be anywhere
between 1 and 4096, and since tx_burst is always decremented by 8
it could possibly underflow, causing an infinite loop.

Signed-off-by: Eden Mikitas <e.mikitas@gmail.com>
---
 hw/ssi/imx_spi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/ssi/imx_spi.c b/hw/ssi/imx_spi.c
index 2dd9a631e1..6fef5c7958 100644
--- a/hw/ssi/imx_spi.c
+++ b/hw/ssi/imx_spi.c
@@ -182,7 +182,7 @@ static void imx_spi_flush_txfifo(IMXSPIState *s)
 
         rx = 0;
 
-        while (tx_burst) {
+        while (tx_burst > 0) {
             uint8_t byte = tx & 0xff;
 
             DPRINTF("writing 0x%02x\n", (uint32_t)byte);
-- 
2.17.1



  reply	other threads:[~2020-05-22 11:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-20 14:32 [PATCH] ssi/imx_spi: Removed unnecessary cast and fixed condition in while statement Eden Mikitas
2020-05-21 16:41 ` Peter Maydell
2020-05-21 18:49   ` Eden Mikitas
2020-05-21 18:56     ` Peter Maydell
2020-05-22 11:50       ` [PATCH 0/2] hw/ssi/imx_spi: 2 Fixes to flush txfifo function in imx_spi Eden Mikitas
2020-05-22 11:50         ` Eden Mikitas [this message]
2020-05-22 15:34           ` [PATCH 1/2] hw/ssi/imx_spi: changed while statement to prevent underflow Alistair Francis
2020-05-22 11:50         ` [PATCH 2/2] hw/ssi/imx_spi: Removed unnecessary cast of rx data received from slave Eden Mikitas
2020-05-22 15:36           ` Alistair Francis
2020-05-29 13:03         ` [PATCH 0/2] hw/ssi/imx_spi: 2 Fixes to flush txfifo function in imx_spi Peter Maydell

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