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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id w25-20020a639359000000b00553dcfc2179sm8659990pgm.52.2023.10.09.09.18.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Oct 2023 09:18:55 -0700 (PDT) Date: Mon, 9 Oct 2023 09:18:52 -0700 From: Kees Cook To: Jason Andryuk Cc: Christian Lamparter , Kalle Valo , "Gustavo A. R. Silva" , linux-wireless@vger.kernel.org, linux-hardening@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Tom Rix , linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH] wifi: p54: Annotate struct p54_cal_database with __counted_by Message-ID: <202310090914.A6BAAB9@keescook> References: <20231006201719.work.356-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Mon, Oct 09, 2023 at 10:55:32AM -0400, Jason Andryuk wrote: > This is the function that creates struct p54_cal_database: > > static struct p54_cal_database *p54_convert_db(struct pda_custom_wrapper *src, > size_t total_len) > { > struct p54_cal_database *dst; > size_t payload_len, entries, entry_size, offset; > > payload_len = le16_to_cpu(src->len); > entries = le16_to_cpu(src->entries); > entry_size = le16_to_cpu(src->entry_size); > offset = le16_to_cpu(src->offset); > if (((entries * entry_size + offset) != payload_len) || > (payload_len + sizeof(*src) != total_len)) > return NULL; > > dst = kmalloc(sizeof(*dst) + payload_len, GFP_KERNEL); > if (!dst) > return NULL; > > dst->entries = entries; > dst->entry_size = entry_size; > dst->offset = offset; > dst->len = payload_len; > > memcpy(dst->data, src->data, payload_len); > return dst; > } > > You can see that kmalloc is performed with `sizeof(*dst) + > payload_len`, and payload_len is assigned to ->len. > > I don't read Coccinelle, but, if this patch was auto-generated, I > wonder if the script has an error. It seems that my Coccinelle script got confused by this: p54_convert_output_limits(): priv->output_limit = kmalloc(data[1] * sizeof(struct pda_channel_output_limit) + sizeof(*priv->output_limit), GFP_KERNEL); ... priv->output_limit->entry_size = sizeof(struct pda_channel_output_limit); priv->output_limit->len = priv->output_limit->entry_size * priv->output_limit->entries + priv->output_limit->offset; It thought "sizeof(struct pda_channel_output_limit)" was the element count, since it wasn't able to identify the array member here. Regardless, I've sent a v2 now. :) -- Kees Cook