Messages in this thread | | | From | Justin Stitt <> | Date | Mon, 16 Oct 2023 11:14:29 -0700 | Subject | Re: [PATCH] qlcnic: replace deprecated strncpy with strscpy |
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On Sat, Oct 14, 2023 at 7:47 PM Kees Cook <keescook@chromium.org> wrote: > > On Thu, Oct 12, 2023 at 07:44:29PM +0000, Justin Stitt wrote: > > 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 fw_info->fw_file_name to be NUL-terminated based on its use > > within _request_firmware_prepare() wherein `name` refers to it: > > | if (firmware_request_builtin_buf(firmware, name, dbuf, size)) { > > | dev_dbg(device, "using built-in %s\n", name); > > | return 0; /* assigned */ > > | } > > ... and with firmware_request_builtin() also via `name`: > > | if (strcmp(name, b_fw->name) == 0) { > > > > There is no evidence that NUL-padding is required. > > > > Considering the above, a suitable replacement is `strscpy` [2] due to > > the fact that it guarantees NUL-termination on the destination buffer > > without unnecessarily NUL-padding. > > When doing the hard-coded value to sizeof(), can you include in the > commit log the rationale for it? For example: > > Additionally replace size macro (QLC_FW_FILE_NAME_LEN) with > sizeof(fw_info->fw_file_name) to more directly tie the maximum buffer > size to the destination buffer: > > struct qlc_83xx_fw_info { > ... > char fw_file_name[QLC_FW_FILE_NAME_LEN]; > }; >
Sure, I'll be doing this from now on to make the change more clear!
> > > > > 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 <justinstitt@google.com> > > --- > > Note: build-tested only. > > > > Found with: $ rg "strncpy\(" > > --- > > drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c | 12 ++++++------ > > 1 file changed, 6 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c > > index c95d56e56c59..b733374b4dc5 100644 > > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c > > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c > > @@ -2092,8 +2092,8 @@ static int qlcnic_83xx_run_post(struct qlcnic_adapter *adapter) > > return -EINVAL; > > } > > > > - strncpy(fw_info->fw_file_name, QLC_83XX_POST_FW_FILE_NAME, > > - QLC_FW_FILE_NAME_LEN); > > + strscpy(fw_info->fw_file_name, QLC_83XX_POST_FW_FILE_NAME, > > + sizeof(fw_info->fw_file_name)); > > > > ret = request_firmware(&fw_info->fw, fw_info->fw_file_name, dev); > > if (ret) { > > @@ -2396,12 +2396,12 @@ static int qlcnic_83xx_get_fw_info(struct qlcnic_adapter *adapter) > > switch (pdev->device) { > > case PCI_DEVICE_ID_QLOGIC_QLE834X: > > case PCI_DEVICE_ID_QLOGIC_QLE8830: > > - strncpy(fw_info->fw_file_name, QLC_83XX_FW_FILE_NAME, > > - QLC_FW_FILE_NAME_LEN); > > + strscpy(fw_info->fw_file_name, QLC_83XX_FW_FILE_NAME, > > + sizeof(fw_info->fw_file_name)); > > break; > > case PCI_DEVICE_ID_QLOGIC_QLE844X: > > - strncpy(fw_info->fw_file_name, QLC_84XX_FW_FILE_NAME, > > - QLC_FW_FILE_NAME_LEN); > > + strscpy(fw_info->fw_file_name, QLC_84XX_FW_FILE_NAME, > > + sizeof(fw_info->fw_file_name)); > > break; > > default: > > dev_err(&pdev->dev, "%s: Invalid device id\n", > > But yes, this all looks right to me. > > Reviewed-by: Kees Cook <keescook@chromium.org> > > -- > Kees Cook
Thanks Justin
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