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Mon, 17 Aug 2026 09:09:36 -0700 (PDT) From: Jeffin Philip To: jeffinphilip14@gmail.com Cc: christophe.jaillet@wanadoo.fr, felipe.balbi@linux.intel.com, gregkh@linuxfoundation.org, kees@kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, stable@vger.kernel.org, stern@rowland.harvard.edu, syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com Subject: [PATCH] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers() Date: Mon, 17 Aug 2026 21:39:16 +0530 Message-ID: <20260817160916.28523-1-jeffinphilip14@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817160319.28251-1-jeffinphilip14@gmail.com> References: <20260817160319.28251-1-jeffinphilip14@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Mon, 17 Aug 2026 21:33:19 +0530, Jeffin Philip wrote: >Kconfig currently sets the limit from 2 to 256 with default as 2. However, >we use that only at build time. So, if we enter during runtime via configfs, >we set page content to 0\0 and get the null pointer dereference. So we will >need to add the check for num < 2 in fsg_opts_num_buffers_store() and return >EINVAL? Upper bound is 256 which is below what kstrtou8() can return anyway. Correction on the last sentence: Upper bound is 256 which is _above_ what kstrtou8() can return anyway.