| Message ID | 20231023-strncpy-drivers-s390-net-qeth_core_main-c-v1-1-e7ce65454446@google.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | e43e6d9582e0dcd20532310dbb9f47dfe7a74ace |
| Headers | show |
| Series | s390/qeth: replace deprecated strncpy with strscpy | expand |
On 23.10.23 21:39, 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 new_entry->dbf_name to be NUL-terminated based on its use with > strcmp(): > | if (strcmp(entry->dbf_name, name) == 0) { > > Moreover, NUL-padding is not required as new_entry is kzalloc'd just > before this assignment: > | new_entry = kzalloc(sizeof(struct qeth_dbf_entry), GFP_KERNEL); > > ... rendering any future NUL-byte assignments (like the ones strncpy() > does) redundant. > > 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. > > 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> LGTM, thank you! Reviewed-by: Thorsten Winkler <twinkler@linux.ibm.com> Tested-by: Thorsten Winkler <twinkler@linux.ibm.com> > --- > Note: build-tested only. > > Found with: $ rg "strncpy\(" > --- > drivers/s390/net/qeth_core_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c > index cd783290bde5..6af2511e070c 100644 > --- a/drivers/s390/net/qeth_core_main.c > +++ b/drivers/s390/net/qeth_core_main.c > @@ -6226,7 +6226,7 @@ static int qeth_add_dbf_entry(struct qeth_card *card, char *name) > new_entry = kzalloc(sizeof(struct qeth_dbf_entry), GFP_KERNEL); > if (!new_entry) > goto err_dbg; > - strncpy(new_entry->dbf_name, name, DBF_NAME_LEN); > + strscpy(new_entry->dbf_name, name, sizeof(new_entry->dbf_name)); > new_entry->dbf_info = card->debug; > mutex_lock(&qeth_dbf_list_mutex); > list_add(&new_entry->dbf_list, &qeth_dbf_list); > > --- > base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c > change-id: 20231023-strncpy-drivers-s390-net-qeth_core_main-c-0b0ee08672ec > > Best regards, > -- > Justin Stitt <justinstitt@google.com> > >
On Mon, Oct 23, 2023 at 07:39:39PM +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 new_entry->dbf_name to be NUL-terminated based on its use with > strcmp(): > | if (strcmp(entry->dbf_name, name) == 0) { > > Moreover, NUL-padding is not required as new_entry is kzalloc'd just > before this assignment: > | new_entry = kzalloc(sizeof(struct qeth_dbf_entry), GFP_KERNEL); > > ... rendering any future NUL-byte assignments (like the ones strncpy() > does) redundant. > > 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. > > 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> struct qeth_dbf_entry { char dbf_name[DBF_NAME_LEN]; The sizeof() replace looks right to me. Reviewed-by: Kees Cook <keescook@chromium.org> -Kees > --- > Note: build-tested only. > > Found with: $ rg "strncpy\(" > --- > drivers/s390/net/qeth_core_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c > index cd783290bde5..6af2511e070c 100644 > --- a/drivers/s390/net/qeth_core_main.c > +++ b/drivers/s390/net/qeth_core_main.c > @@ -6226,7 +6226,7 @@ static int qeth_add_dbf_entry(struct qeth_card *card, char *name) > new_entry = kzalloc(sizeof(struct qeth_dbf_entry), GFP_KERNEL); > if (!new_entry) > goto err_dbg; > - strncpy(new_entry->dbf_name, name, DBF_NAME_LEN); > + strscpy(new_entry->dbf_name, name, sizeof(new_entry->dbf_name)); > new_entry->dbf_info = card->debug; > mutex_lock(&qeth_dbf_list_mutex); > list_add(&new_entry->dbf_list, &qeth_dbf_list); > > --- > base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c > change-id: 20231023-strncpy-drivers-s390-net-qeth_core_main-c-0b0ee08672ec > > Best regards, > -- > Justin Stitt <justinstitt@google.com> > >
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Mon, 23 Oct 2023 19:39:39 +0000 you 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 new_entry->dbf_name to be NUL-terminated based on its use with > strcmp(): > | if (strcmp(entry->dbf_name, name) == 0) { > > [...] Here is the summary with links: - s390/qeth: replace deprecated strncpy with strscpy https://git.kernel.org/netdev/net-next/c/e43e6d9582e0 You are awesome, thank you!
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index cd783290bde5..6af2511e070c 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -6226,7 +6226,7 @@ static int qeth_add_dbf_entry(struct qeth_card *card, char *name) new_entry = kzalloc(sizeof(struct qeth_dbf_entry), GFP_KERNEL); if (!new_entry) goto err_dbg; - strncpy(new_entry->dbf_name, name, DBF_NAME_LEN); + strscpy(new_entry->dbf_name, name, sizeof(new_entry->dbf_name)); new_entry->dbf_info = card->debug; mutex_lock(&qeth_dbf_list_mutex); list_add(&new_entry->dbf_list, &qeth_dbf_list);
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 new_entry->dbf_name to be NUL-terminated based on its use with strcmp(): | if (strcmp(entry->dbf_name, name) == 0) { Moreover, NUL-padding is not required as new_entry is kzalloc'd just before this assignment: | new_entry = kzalloc(sizeof(struct qeth_dbf_entry), GFP_KERNEL); ... rendering any future NUL-byte assignments (like the ones strncpy() does) redundant. 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. 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/s390/net/qeth_core_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c change-id: 20231023-strncpy-drivers-s390-net-qeth_core_main-c-0b0ee08672ec Best regards, -- Justin Stitt <justinstitt@google.com>