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(host-127-24.cafrjco.fresno.ca.us.clients.pavlovmedia.net. [68.180.127.24]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2ee38d79eb9sm24874944eec.8.2026.05.04.18.47.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 May 2026 18:47:01 -0700 (PDT) From: Ethan Nelson-Moore To: linux-usb@vger.kernel.org, netdev@vger.kernel.org Cc: Ethan Nelson-Moore , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Andy Shevchenko , Peter Korsgaard Subject: [PATCH net-next] net: usb: mcs7830: adjust incorrect comment implying a vulnerability Date: Mon, 4 May 2026 18:46:30 -0700 Message-ID: <20260505014634.49100-1-enelsonmoore@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The mcs7830 driver contains a comment indicating that mcs7830_get_regs leaks uninitialized memory to user space on some devices. If true, this would indicate a security vulnerability. However, I investigated the issue and found that it is not true because ethtool_get_regs (in net/ethtool/ioctl.c) uses vzalloc to allocate its buffer, which zeroes the memory. Update the comment to explain this behavior. Signed-off-by: Ethan Nelson-Moore --- drivers/net/usb/mcs7830.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/usb/mcs7830.c b/drivers/net/usb/mcs7830.c index d6698f30218d..dfdc7bd74166 100644 --- a/drivers/net/usb/mcs7830.c +++ b/drivers/net/usb/mcs7830.c @@ -22,7 +22,8 @@ * - implement get_eeprom/[set_eeprom] * - switch PHY on/off on ifup/ifdown (perhaps in usbnet.c, via MII) * - mcs7830_get_regs() handling is weird: for rev 2 we return 32 regs, - * can access only ~ 24, remaining user buffer is uninitialized garbage + * can access only ~ 24; this is not a security vulnerability because + * ethtool_get_regs allocates a zeroed buffer * - anything else? */ -- 2.43.0