`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@xxxxxxxxxxxxxxx Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> --- Note: build-tested only. --- drivers/mmc/host/vub300.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) 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); --- base-commit: 6465e260f48790807eef06b583b38ca9789b6072 change-id: 20230927-strncpy-drivers-mmc-host-vub300-c-b7b39f82e584 Best regards, -- Justin Stitt <justinstitt@xxxxxxxxxx>
