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b=H4sIAKHOE2UC/x3NMQ6DMAxA0asgz7WUJiCgV6kYmmDAAwHZIWqFu Hsjxrf8f4KSMCm8qhOEMitvseD5qCAsnzgT8lgM1lhnetuiJolh/+EonEkU1zXgsmnCfHhnDAb 0rXf91FlquhpKZxea+Hs/3sN1/QGl6Ar9cwAAAA== X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1695796897; l=5550; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=YPZfe2Wyy7QnsQhjAGzhJqwDXvMubl0PpcqCu4zLYvI=; b=DVmX3rW9B9/NdIy6Sx1tPZhSRgJUBHuGbPKG2EobRxqUmLqriHBIfHZa6/44chl99vMNeGrDV ufoIE9dRsqwDdET0IHyIJy7USZl/n6oXtJwqFm9YsEIrFepousjKoKk X-Mailer: b4 0.12.3 Message-ID: <20230927-strncpy-drivers-mmc-host-vub300-c-v1-1-77426f62eef4@google.com> Subject: [PATCH] mmc: vub300: replace deprecated strncpy with strscpy From: Justin Stitt To: Ulf Hansson Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Tue, 26 Sep 2023 23:41:49 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778182791120180961 X-GMAIL-MSGID: 1778182791120180961 `strncpy` is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. We expect `vub300->vub_name` to be NUL-terminated based on its uses with format strings: | dev_info(&vub300->udev->dev, "using %s for SDIO offload processing\n", | vub300->vub_name); NUL-padding is not needed. We can see cleaning out vub_name simply consists of: | vub300->vub_name[0] = 0; Considering the above, for all 11 cases a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. To be clear, there is no existing bug in the current implementation as the string literals are all small enough as to not cause a buffer overread. Nonetheless, this gets us 11 steps closer to removing strncpy uses. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt --- Note: build-tested only. --- drivers/mmc/host/vub300.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) --- base-commit: 6465e260f48790807eef06b583b38ca9789b6072 change-id: 20230927-strncpy-drivers-mmc-host-vub300-c-b7b39f82e584 Best regards, -- Justin Stitt diff --git a/drivers/mmc/host/vub300.c b/drivers/mmc/host/vub300.c index 9ec593d52f0f..de3f443f5fdc 100644 --- a/drivers/mmc/host/vub300.c +++ b/drivers/mmc/host/vub300.c @@ -512,7 +512,7 @@ static void new_system_port_status(struct vub300_mmc_host *vub300) vub300->card_present = 1; vub300->bus_width = 0; if (disable_offload_processing) - strncpy(vub300->vub_name, "EMPTY Processing Disabled", + strscpy(vub300->vub_name, "EMPTY Processing Disabled", sizeof(vub300->vub_name)); else vub300->vub_name[0] = 0; @@ -1216,7 +1216,7 @@ static void __download_offload_pseudocode(struct vub300_mmc_host *vub300, dev_err(&vub300->udev->dev, "corrupt offload pseudocode in firmware %s\n", vub300->vub_name); - strncpy(vub300->vub_name, "corrupt offload pseudocode", + strscpy(vub300->vub_name, "corrupt offload pseudocode", sizeof(vub300->vub_name)); return; } @@ -1250,7 +1250,7 @@ static void __download_offload_pseudocode(struct vub300_mmc_host *vub300, "not enough memory for xfer buffer to send" " INTERRUPT_PSEUDOCODE for %s %s\n", fw->data, vub300->vub_name); - strncpy(vub300->vub_name, + strscpy(vub300->vub_name, "SDIO interrupt pseudocode download failed", sizeof(vub300->vub_name)); return; @@ -1259,7 +1259,7 @@ static void __download_offload_pseudocode(struct vub300_mmc_host *vub300, dev_err(&vub300->udev->dev, "corrupt interrupt pseudocode in firmware %s %s\n", fw->data, vub300->vub_name); - strncpy(vub300->vub_name, "corrupt interrupt pseudocode", + strscpy(vub300->vub_name, "corrupt interrupt pseudocode", sizeof(vub300->vub_name)); return; } @@ -1293,7 +1293,7 @@ static void __download_offload_pseudocode(struct vub300_mmc_host *vub300, "not enough memory for xfer buffer to send" " TRANSFER_PSEUDOCODE for %s %s\n", fw->data, vub300->vub_name); - strncpy(vub300->vub_name, + strscpy(vub300->vub_name, "SDIO transfer pseudocode download failed", sizeof(vub300->vub_name)); return; @@ -1302,7 +1302,7 @@ static void __download_offload_pseudocode(struct vub300_mmc_host *vub300, dev_err(&vub300->udev->dev, "corrupt transfer pseudocode in firmware %s %s\n", fw->data, vub300->vub_name); - strncpy(vub300->vub_name, "corrupt transfer pseudocode", + strscpy(vub300->vub_name, "corrupt transfer pseudocode", sizeof(vub300->vub_name)); return; } @@ -1336,13 +1336,13 @@ static void __download_offload_pseudocode(struct vub300_mmc_host *vub300, dev_err(&vub300->udev->dev, "corrupt dynamic registers in firmware %s\n", vub300->vub_name); - strncpy(vub300->vub_name, "corrupt dynamic registers", + strscpy(vub300->vub_name, "corrupt dynamic registers", sizeof(vub300->vub_name)); return; } copy_error_message: - strncpy(vub300->vub_name, "SDIO pseudocode download failed", + strscpy(vub300->vub_name, "SDIO pseudocode download failed", sizeof(vub300->vub_name)); } @@ -1370,11 +1370,11 @@ static void download_offload_pseudocode(struct vub300_mmc_host *vub300) vub300->vub_name); retval = request_firmware(&fw, vub300->vub_name, &card->dev); if (retval < 0) { - strncpy(vub300->vub_name, "vub_default.bin", + strscpy(vub300->vub_name, "vub_default.bin", sizeof(vub300->vub_name)); retval = request_firmware(&fw, vub300->vub_name, &card->dev); if (retval < 0) { - strncpy(vub300->vub_name, + strscpy(vub300->vub_name, "no SDIO offload firmware found", sizeof(vub300->vub_name)); } else { @@ -1758,7 +1758,7 @@ static void vub300_cmndwork_thread(struct work_struct *work) * has been already downloaded to the VUB300 chip */ } else if (0 == vub300->mmc->card->sdio_funcs) { - strncpy(vub300->vub_name, "SD memory device", + strscpy(vub300->vub_name, "SD memory device", sizeof(vub300->vub_name)); } else { download_offload_pseudocode(vub300);