From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C2930392C27; Sat, 17 Oct 2026 16:52:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792255969; cv=none; b=o/j7PZ3EdW5c8La6SlQ3tCBB6ny/BJWrb2Yz3q7lG0xKOD//+ZkAAuFt4L8nwdgjWGE5reEEyY7kc87Gnvlpe6JG8zubNM0h5sfGt9Z3X70761IOEdoYcKA6ChE5KY9BbQ3JU9YCdmPziZV7sfgBdevvExJON1IHIT0vWt3/ISc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792255969; c=relaxed/simple; bh=2Yr7TX6rtHRCko5iLmVC63RLRczDHp1kux4CF2+edYM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OjAB1eHABivlqOgb4DkLZKWvYEzycBeNAz8LNZA9ylGaQz6vn+fLiPP58PSXnwNluoViIKx6w+AOlRMQWT8KIwk8kPbviLgU5vSdBdssj5AEU1C0rNZnH9fAeWnGFVKC0zBYT0oVbGf5blCRfIdwIEfeNC8PPyk/OCz+T5BkDDQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=u3cCAStq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="u3cCAStq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19A621F000C4; Sat, 17 Oct 2026 16:52:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792255968; bh=sxi2e6aq8gymzohTFQhiYesDx41yovS6XRTTLxdZ2Lw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=u3cCAStqk66+UzIUhh0E2RJKH4bwsr+KiDeqEAMcz+9k1ppW6nrvFIONv/ke7EWX1 taVbaE+QgUbRo+eOdHVF4W6lavHIqbIprnDkyA7tjHDMsWWURvuTGES/ReQeKuRCpI 1hGL5p4lMMg2GZnMAxIeeZw9grymykJl1Oshu4L8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com, stable , Jeffin Philip , Alan Stern , Sasha Levin Subject: [PATCH 6.6 0082/1674] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers() Date: Sat, 17 Oct 2026 17:39:14 +0200 Message-ID: <20261017160433.236545431@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeffin Philip [ Upstream commit 2c0f5ca48674a5b5f9fa4a9c3325aa48053af0bc ] Previously fsg_num_buffers_validate() was removed as it was not necessary due to Kconfig setting the limits for n from 2 to 256 with default as 2. However, setting the page content in such a way that kstrtou8() reflects n value as either 0 or 1 bypasses these restrictions leading to a null pointer dereference if n is 0. Fix this by adding a check for n < 2 and returning -EINVAL if n is either 0 or 1 consistent with Kconfig logic. Reported-by: syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=791be35f1fbcc85d06d7 Fixes: fe5a6c48fd95 ("usb: gadget: storage: get rid of fsg_num_buffers_validate()") Cc: stable Signed-off-by: Jeffin Philip Acked-by: Alan Stern Link: https://patch.msgid.link/20260818035904.10324-1-jeffinphilip14@gmail.com Signed-off-by: Greg Kroah-Hartman [ adjusted context to retain the branch’s existing kcalloc() call instead of kzalloc_objs(). ] Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_mass_storage.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c index 01c35deaefe1b..4a7de2ba91cb2 100644 --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -2748,6 +2748,9 @@ int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n) struct fsg_buffhd *bh, *buffhds; int i; + if (n < 2) + return -EINVAL; + buffhds = kcalloc(n, sizeof(*buffhds), GFP_KERNEL); if (!buffhds) return -ENOMEM; -- 2.53.0