| Message ID | 20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-v1-1-f01a23394eab@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | i40e: use scnprintf over strncpy+strncat | expand |
On 10/10/2023 1:53 PM, 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. > > Moreover, `strncat` shouldn't really be used either as per > fortify-string.h: > * Do not use this function. While FORTIFY_SOURCE tries to avoid > * read and write overflows, this is only possible when the sizes > * of @p and @q are known to the compiler. Prefer building the > * string with formatting, via scnprintf() or similar. > > Instead, use `scnprintf` with "%s%s" format string. This code is now > more readable and robust. Please see my comments on the igbvf patch.
On Tue, Oct 10, 2023 at 08:53:00PM +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. > > Moreover, `strncat` shouldn't really be used either as per > fortify-string.h: > * Do not use this function. While FORTIFY_SOURCE tries to avoid > * read and write overflows, this is only possible when the sizes > * of @p and @q are known to the compiler. Prefer building the > * string with formatting, via scnprintf() or similar. > > Instead, use `scnprintf` with "%s%s" format string. This code is now > more readable and robust. > > 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. > --- > drivers/net/ethernet/intel/i40e/i40e_ddp.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_ddp.c b/drivers/net/ethernet/intel/i40e/i40e_ddp.c > index 0e72abd178ae..ec25e4be250f 100644 > --- a/drivers/net/ethernet/intel/i40e/i40e_ddp.c > +++ b/drivers/net/ethernet/intel/i40e/i40e_ddp.c > @@ -438,10 +438,9 @@ int i40e_ddp_flash(struct net_device *netdev, struct ethtool_flash *flash) > char profile_name[sizeof(I40E_DDP_PROFILE_PATH) > + I40E_DDP_PROFILE_NAME_MAX]; > > - profile_name[sizeof(profile_name) - 1] = 0; > - strncpy(profile_name, I40E_DDP_PROFILE_PATH, > - sizeof(profile_name) - 1); > - strncat(profile_name, flash->data, I40E_DDP_PROFILE_NAME_MAX); > + scnprintf(profile_name, sizeof(profile_name), "%s%s", > + I40E_DDP_PROFILE_PATH, flash->data); > + > /* Load DDP recipe. */ > status = request_firmware(&ddp_config, profile_name, > &netdev->dev); > > --- > base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 > change-id: 20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-dd7f20b7ed5d > > Best regards, > -- > Justin Stitt <justinstitt@google.com> > Hi, this patch was bundled up with some others. It has a new home: https://lore.kernel.org/all/20231010-netdev-replace-strncpy-resend-as-series-v1-0-caf9f0f2f021@google.com/
diff --git a/drivers/net/ethernet/intel/i40e/i40e_ddp.c b/drivers/net/ethernet/intel/i40e/i40e_ddp.c index 0e72abd178ae..ec25e4be250f 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_ddp.c +++ b/drivers/net/ethernet/intel/i40e/i40e_ddp.c @@ -438,10 +438,9 @@ int i40e_ddp_flash(struct net_device *netdev, struct ethtool_flash *flash) char profile_name[sizeof(I40E_DDP_PROFILE_PATH) + I40E_DDP_PROFILE_NAME_MAX]; - profile_name[sizeof(profile_name) - 1] = 0; - strncpy(profile_name, I40E_DDP_PROFILE_PATH, - sizeof(profile_name) - 1); - strncat(profile_name, flash->data, I40E_DDP_PROFILE_NAME_MAX); + scnprintf(profile_name, sizeof(profile_name), "%s%s", + I40E_DDP_PROFILE_PATH, flash->data); + /* Load DDP recipe. */ status = request_firmware(&ddp_config, profile_name, &netdev->dev);
`strncpy` is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. Moreover, `strncat` shouldn't really be used either as per fortify-string.h: * Do not use this function. While FORTIFY_SOURCE tries to avoid * read and write overflows, this is only possible when the sizes * of @p and @q are known to the compiler. Prefer building the * string with formatting, via scnprintf() or similar. Instead, use `scnprintf` with "%s%s" format string. This code is now more readable and robust. 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. --- drivers/net/ethernet/intel/i40e/i40e_ddp.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 change-id: 20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-dd7f20b7ed5d Best regards, -- Justin Stitt <justinstitt@google.com>