From: Evan Green <evgreen@chromium.org>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Evan Green <evgreen@chromium.org>,
stable@vger.kernel.org,
Nick Desaulniers <nick.desaulniers@gmail.com>,
Allison Randal <allison@lohutok.net>,
Andrew Duggan <aduggan@synaptics.com>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
Enrico Weigelt <info@metux.net>,
Thomas Gleixner <tglx@linutronix.de>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] Input: synaptics-rmi4 - Really fix attn_data use-after-free
Date: Mon, 27 Apr 2020 14:55:48 -0700 [thread overview]
Message-ID: <20200427145537.1.Ic8f898e0147beeee2c005ee7b20f1aebdef1e7eb@changeid> (raw)
Fix a use-after-free noticed by running with KASAN enabled. If
rmi_irq_fn() is run twice in a row, then rmi_f11_attention() (among
others) will end up reading from drvdata->attn_data.data, which was
freed and left dangling in rmi_irq_fn().
Commit 55edde9fff1a ("Input: synaptics-rmi4 - prevent UAF reported by
KASAN") correctly identified and analyzed this bug. However the attempted
fix only NULLed out a local variable, missing the fact that
drvdata->attn_data is a struct, not a pointer.
NULL out the correct pointer in the driver data to prevent the attention
functions from copying from it.
Fixes: 55edde9fff1a ("Input: synaptics-rmi4 - prevent UAF reported by KASAN")
Fixes: b908d3cd812a ("Input: synaptics-rmi4 - allow to add attention data")
Signed-off-by: Evan Green <evgreen@chromium.org>
Cc: stable@vger.kernel.org
Cc: Nick Desaulniers <nick.desaulniers@gmail.com>
---
drivers/input/rmi4/rmi_driver.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
index 190b9974526bb..c18e1a25bca6e 100644
--- a/drivers/input/rmi4/rmi_driver.c
+++ b/drivers/input/rmi4/rmi_driver.c
@@ -205,7 +205,7 @@ static irqreturn_t rmi_irq_fn(int irq, void *dev_id)
if (count) {
kfree(attn_data.data);
- attn_data.data = NULL;
+ drvdata->attn_data.data = NULL;
}
if (!kfifo_is_empty(&drvdata->attn_fifo))
--
2.24.1
next reply other threads:[~2020-04-27 21:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-27 21:55 Evan Green [this message]
2020-04-28 1:11 ` [PATCH] Input: synaptics-rmi4 - Really fix attn_data use-after-free Dmitry Torokhov
2020-04-28 15:53 ` Evan Green
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