| Message ID | 20230913-strncpy-drivers-cpufreq-cpufreq-c-v1-1-f1608bfeff63@google.com |
|---|---|
| State | Accepted |
| Commit | 0faf84caee63a5f331bda130265fdceb7d4101b5 |
| Headers | show |
| Series | cpufreq: refactor deprecated strncpy | expand |
On Wed, Sep 13, 2023 at 12:07:21AM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We should prefer more robust and less ambiguous string interfaces. > > Both `policy->last_governor` and `default_governor` are expected to be > NUL-terminated which is shown by their heavy usage with other string > apis like `strcmp`. > > A suitable replacement is `strscpy` [2] due to the fact that it guarantees > NUL-termination on the destination buffer. > > 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> All looks sensible to me. Reviewed-by: Kees Cook <keescook@chromium.org>
On Wed, 13 Sep 2023 00:07:21 +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We should prefer more robust and less ambiguous string interfaces. > > Both `policy->last_governor` and `default_governor` are expected to be > NUL-terminated which is shown by their heavy usage with other string > apis like `strcmp`. > > [...] Applied to for-next/hardening, thanks! [1/1] cpufreq: refactor deprecated strncpy https://git.kernel.org/kees/c/598b1b1c8f35 Take care,
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 50bbc969ffe5..3eb851a03fce 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1607,7 +1607,7 @@ static void __cpufreq_offline(unsigned int cpu, struct cpufreq_policy *policy) } if (has_target()) - strncpy(policy->last_governor, policy->governor->name, + strscpy(policy->last_governor, policy->governor->name, CPUFREQ_NAME_LEN); else policy->last_policy = policy->policy; @@ -2951,7 +2951,7 @@ static int __init cpufreq_core_init(void) BUG_ON(!cpufreq_global_kobject); if (!strlen(default_governor)) - strncpy(default_governor, gov->name, CPUFREQ_NAME_LEN); + strscpy(default_governor, gov->name, CPUFREQ_NAME_LEN); return 0; }
`strncpy` is deprecated for use on NUL-terminated destination strings [1]. We should prefer more robust and less ambiguous string interfaces. Both `policy->last_governor` and `default_governor` are expected to be NUL-terminated which is shown by their heavy usage with other string apis like `strcmp`. A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer. 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 --- drivers/cpufreq/cpufreq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c change-id: 20230912-strncpy-drivers-cpufreq-cpufreq-c-1d800044b007 Best regards, -- Justin Stitt <justinstitt@google.com>