strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
This kernel config option is simply assigned with the resume_file
buffer. It should be NUL-terminated but not necessarily NUL-padded as
per its further usage with other string apis:
| static int __init find_resume_device(void)
| {
| if (!strlen(resume_file))
| return -ENOENT;
|
| pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
Use strscpy [2] as it guarantees NUL-termination on the destination
buffer. Specifically, use the new 2-argument version of strscpy()
introduced in Commit e6584c3964f2f ("string: Allow 2-argument
strscpy()").
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: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
Note: build-tested only.
Found with: $ rg "strncpy\("
---
kernel/power/hibernate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 43b1a82e800c..0a213f69a9e4 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -1361,7 +1361,7 @@ static int __init resume_setup(char *str)
if (noresume)
return 1;
- strncpy(resume_file, str, 255);
+ strscpy(resume_file, str);
return 1;
}
---
base-commit: d7ad0581567927c433918bb5f06f3d29f89807d3
change-id: 20240412-strncpy-kernel-power-hibernate-c-77985696443c
Best regards,
--
Justin Stitt <[email protected]>
On Mon, Apr 29, 2024 at 08:50:30PM +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.
>
> This kernel config option is simply assigned with the resume_file
> buffer. It should be NUL-terminated but not necessarily NUL-padded as
> per its further usage with other string apis:
> | static int __init find_resume_device(void)
> | {
> | if (!strlen(resume_file))
> | return -ENOENT;
> |
> | pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
>
> Use strscpy [2] as it guarantees NUL-termination on the destination
> buffer. Specifically, use the new 2-argument version of strscpy()
> introduced in Commit e6584c3964f2f ("string: Allow 2-argument
> strscpy()").
>
> 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> ---
> Note: build-tested only.
>
> Found with: $ rg "strncpy\("
> ---
> kernel/power/hibernate.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index 43b1a82e800c..0a213f69a9e4 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -1361,7 +1361,7 @@ static int __init resume_setup(char *str)
> if (noresume)
> return 1;
>
> - strncpy(resume_file, str, 255);
> + strscpy(resume_file, str);
> return 1;
> }
>
Yup, this looks correct to me. resume_file is:
static char resume_file[256] = CONFIG_PM_STD_PARTITION;
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
On Apr 29, 2024 at 20:50:30 +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.
>
> This kernel config option is simply assigned with the resume_file
> buffer. It should be NUL-terminated but not necessarily NUL-padded as
> per its further usage with other string apis:
> | static int __init find_resume_device(void)
> | {
> | if (!strlen(resume_file))
> | return -ENOENT;
> |
> | pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
>
> Use strscpy [2] as it guarantees NUL-termination on the destination
> buffer. Specifically, use the new 2-argument version of strscpy()
> introduced in Commit e6584c3964f2f ("string: Allow 2-argument
> strscpy()").
>
> 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> ---
[...]
Reviewed-by: Dhruva Gole <[email protected]>
--
Best regards,
Dhruva Gole <[email protected]>
On Tue, Apr 30, 2024 at 11:36 AM Dhruva Gole <[email protected]> wrote:
>
> On Apr 29, 2024 at 20:50:30 +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.
> >
> > This kernel config option is simply assigned with the resume_file
> > buffer. It should be NUL-terminated but not necessarily NUL-padded as
> > per its further usage with other string apis:
> > | static int __init find_resume_device(void)
> > | {
> > | if (!strlen(resume_file))
> > | return -ENOENT;
> > |
> > | pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
> >
> > Use strscpy [2] as it guarantees NUL-termination on the destination
> > buffer. Specifically, use the new 2-argument version of strscpy()
> > introduced in Commit e6584c3964f2f ("string: Allow 2-argument
> > strscpy()").
> >
> > 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.enhtml [2]
> > Link: https://github.com/KSPP/linux/issues/90
> > Cc: [email protected]
> > Signed-off-by: Justin Stitt <[email protected]>
> > ---
> [...]
>
> Reviewed-by: Dhruva Gole <[email protected]>
Applied as 6.10 material, thanks!