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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Colin Ian King <colin.king@canonical.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 097/306] usbip: tools: fix atoi() on non-null terminated string
Date:   Wed, 27 Nov 2019 21:29:07 +0100
Message-Id: <20191127203121.975683825@linuxfoundation.org>
In-Reply-To: <20191127203114.766709977@linuxfoundation.org>
References: <20191127203114.766709977@linuxfoundation.org>
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From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit e325808c0051b16729ffd472ff887c6cae5c6317 ]

Currently the call to atoi is being passed a single char string
that is not null terminated, so there is a potential read overrun
along the stack when parsing for an integer value.  Fix this by
instead using a 2 char string that is initialized to all zeros
to ensure that a 1 char read into the string is always terminated
with a \0.

Detected by cppcheck:
"Invalid atoi() argument nr 1. A nul-terminated string is required."

Fixes: 3391ba0e2792 ("usbip: tools: Extract generic code to be shared with vudc backend")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/usb/usbip/libsrc/usbip_host_common.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
index dc93fadbee963..d79c7581b175f 100644
--- a/tools/usb/usbip/libsrc/usbip_host_common.c
+++ b/tools/usb/usbip/libsrc/usbip_host_common.c
@@ -43,7 +43,7 @@ static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 	int size;
 	int fd;
 	int length;
-	char status;
+	char status[2] = { 0 };
 	int value = 0;
 
 	size = snprintf(status_attr_path, sizeof(status_attr_path),
@@ -61,14 +61,14 @@ static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 		return -1;
 	}
 
-	length = read(fd, &status, 1);
+	length = read(fd, status, 1);
 	if (length < 0) {
 		err("error reading attribute %s", status_attr_path);
 		close(fd);
 		return -1;
 	}
 
-	value = atoi(&status);
+	value = atoi(status);
 
 	return value;
 }
-- 
2.20.1