| Message ID | 20230927-strncpy-drivers-misc-c2port-core-c-v1-1-978f6d220a54@google.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 1b6f457b835447a787a729dbd421653f865921d0 |
| Headers | show |
| Series | c2port: replace deprecated strncpy with strscpy | expand |
On Wed, Sep 27, 2023, at 07:20, 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 `c2dev->name` to be NUL-terminated based on its usage with > format strings: > | dev_info(c2dev->dev, "C2 port %s removed\n", c2dev->name); > > Moreover, NUL-padding is _not_ required as c2dev is zero-allocated: > | c2dev = kzalloc(sizeof(struct c2port_device), GFP_KERNEL); > > 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. > > Let's also drop `C2PORT_NAME_LEN - 1` for `sizeof(dest)` which is more > idiomatic strscpy usage. > > 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> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/drivers/misc/c2port/core.c b/drivers/misc/c2port/core.c index f574c83b82cf..2bb1dd2511f9 100644 --- a/drivers/misc/c2port/core.c +++ b/drivers/misc/c2port/core.c @@ -923,7 +923,7 @@ struct c2port_device *c2port_device_register(char *name, } dev_set_drvdata(c2dev->dev, c2dev); - strncpy(c2dev->name, name, C2PORT_NAME_LEN - 1); + strscpy(c2dev->name, name, sizeof(c2dev->name)); c2dev->ops = ops; mutex_init(&c2dev->mutex);
`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 `c2dev->name` to be NUL-terminated based on its usage with format strings: | dev_info(c2dev->dev, "C2 port %s removed\n", c2dev->name); Moreover, NUL-padding is _not_ required as c2dev is zero-allocated: | c2dev = kzalloc(sizeof(struct c2port_device), GFP_KERNEL); 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. Let's also drop `C2PORT_NAME_LEN - 1` for `sizeof(dest)` which is more idiomatic strscpy usage. 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/misc/c2port/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 6465e260f48790807eef06b583b38ca9789b6072 change-id: 20230927-strncpy-drivers-misc-c2port-core-c-aa196361fec5 Best regards, -- Justin Stitt <justinstitt@google.com>