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a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1775703010; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Ca/hCivNQ+GfsLCWu5A+fqrBPvC83j+aR85nKjfB7dw=; b=dDL0bvUWqixxzImVwTQW3s6pSadl+H8bX66XM/cBycE7ropjpUUEn4ABPu+/7YHquTXo6m Y0uVAtPUQ+C1X3AeAvX7ACDyFaE0qjX7NDoCXAt/tKTLbWNOdOnbKyI4RfoXzaMjNEm9A7 RR7/73nAkVakCgSJXPjd2Ap/DBo7O7jM6u8XiWpg2U2VPNFklH9FsgcHIoPZez5iv+nmTS vYaRGp9jMRcw021wTPzAzbBZY2SKT1SqD2f+y4vYRX+dNQ0pT2iZCcEXauq9+rgPzf8fvK CRtaRv1P0mzIdRqUsSBqSt8VvmL24AldzHkW7qixPBnVu2ZwwaHX/DvtoKuIPA== To: netdev@vger.kernel.org Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, jreuter@yaina.de, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, Mashiro Chen , stable@vger.kernel.org Subject: [PATCH v2 net 2/2] net: hamradio: scc: validate bufsize in SIOCSCCSMEM ioctl Date: Thu, 9 Apr 2026 10:49:27 +0800 Message-ID: <20260409024927.24397-3-mashiro.chen@mailbox.org> In-Reply-To: <20260409024927.24397-1-mashiro.chen@mailbox.org> References: <20260409024927.24397-1-mashiro.chen@mailbox.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-MBO-RS-ID: f6290bd8d58f4ba352a X-MBO-RS-META: 3e56zqrj9h4snafz64i6ixnrmmbcwrkd X-Rspamd-Queue-Id: 4frktr23rGzB14V The SIOCSCCSMEM ioctl copies a scc_mem_config from user space and assigns its bufsize field directly to scc->stat.bufsize without any range validation: scc->stat.bufsize = memcfg.bufsize; If a privileged user (CAP_SYS_RAWIO) sets bufsize to 0, the receive interrupt handler later calls dev_alloc_skb(0) and immediately writes a KISS type byte via skb_put_u8() into a zero-capacity socket buffer, corrupting the adjacent skb_shared_info region. Reject bufsize values smaller than 16; this is large enough to hold at least one KISS header byte plus useful data. Cc: stable@vger.kernel.org Cc: linux-hams@vger.kernel.org Signed-off-by: Mashiro Chen --- drivers/net/hamradio/scc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/hamradio/scc.c b/drivers/net/hamradio/scc.c index ae5048efde686a..8569db4a71401c 100644 --- a/drivers/net/hamradio/scc.c +++ b/drivers/net/hamradio/scc.c @@ -1909,6 +1909,8 @@ static int scc_net_siocdevprivate(struct net_device *dev, if (!capable(CAP_SYS_RAWIO)) return -EPERM; if (!arg || copy_from_user(&memcfg, arg, sizeof(memcfg))) return -EINVAL; + if (memcfg.bufsize < 16) + return -EINVAL; scc->stat.bufsize = memcfg.bufsize; return 0; -- 2.53.0