| Message ID | 20231011-strncpy-drivers-net-ethernet-netronome-nfp-nfpcore-nfp_resource-c-v1-1-7d1c984f0eba@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | d273e99b5623bba5a9b63c18ee5ef597c2fdabc1 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | nfp: replace deprecated strncpy with strscpy | expand |
On Wed, Oct 11, 2023 at 09:48:39PM +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 res->name to be NUL-terminated based on its usage with format > strings: > | dev_err(cpp->dev.parent, "Dangling area: %d:%d:%d:0x%0llx-0x%0llx%s%s\n", > | NFP_CPP_ID_TARGET_of(res->cpp_id), > | NFP_CPP_ID_ACTION_of(res->cpp_id), > | NFP_CPP_ID_TOKEN_of(res->cpp_id), > | res->start, res->end, > | res->name ? " " : "", > | res->name ? res->name : ""); > ... and with strcmp() > | if (!strcmp(res->name, NFP_RESOURCE_TBL_NAME)) { > > Moreover, NUL-padding is not required as `res` is already > zero-allocated: > | res = kzalloc(sizeof(*res), 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 opt to use the more idiomatic strscpy() usage of (dest, src, > sizeof(dest)) rather than (dest, src, SOME_LEN). > > Typically the pattern of 1) allocate memory for string, 2) copy string > into freshly-allocated memory is a candidate for kmemdup_nul() but in > this case we are allocating the entirety of the `res` struct and that > should stay as is. As mentioned above, simple 1:1 replacement of strncpy > -> 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: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> > --- > Note: build-tested only. > > Found with: $ rg "strncpy\(" > --- > drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c > index ce7492a6a98f..279ea0b56955 100644 > --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c > +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c > @@ -159,7 +159,7 @@ nfp_resource_acquire(struct nfp_cpp *cpp, const char *name) > if (!res) > return ERR_PTR(-ENOMEM); > > - strncpy(res->name, name, NFP_RESOURCE_ENTRY_NAME_SZ); > + strscpy(res->name, name, sizeof(res->name)); struct nfp_resource { char name[NFP_RESOURCE_ENTRY_NAME_SZ + 1]; Yup, this is doing the implicit string size reduction. Reviewed-by: Kees Cook <keescook@chromium.org>
On Wed, Oct 11, 2023 at 09:48:39PM +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 res->name to be NUL-terminated based on its usage with format > strings: > | dev_err(cpp->dev.parent, "Dangling area: %d:%d:%d:0x%0llx-0x%0llx%s%s\n", > | NFP_CPP_ID_TARGET_of(res->cpp_id), > | NFP_CPP_ID_ACTION_of(res->cpp_id), > | NFP_CPP_ID_TOKEN_of(res->cpp_id), > | res->start, res->end, > | res->name ? " " : "", > | res->name ? res->name : ""); > ... and with strcmp() > | if (!strcmp(res->name, NFP_RESOURCE_TBL_NAME)) { > > Moreover, NUL-padding is not required as `res` is already > zero-allocated: > | res = kzalloc(sizeof(*res), 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 opt to use the more idiomatic strscpy() usage of (dest, src, > sizeof(dest)) rather than (dest, src, SOME_LEN). > > Typically the pattern of 1) allocate memory for string, 2) copy string > into freshly-allocated memory is a candidate for kmemdup_nul() but in > this case we are allocating the entirety of the `res` struct and that > should stay as is. As mentioned above, simple 1:1 replacement of strncpy > -> 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: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> > --- > Note: build-tested only. > > Found with: $ rg "strncpy\(" Thanks Justin, I did also now check it on a nfp. Acked-by: Louis Peens <louis.peens@corigine.com> > --- > drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c > index ce7492a6a98f..279ea0b56955 100644 > --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c > +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c > @@ -159,7 +159,7 @@ nfp_resource_acquire(struct nfp_cpp *cpp, const char *name) > if (!res) > return ERR_PTR(-ENOMEM); > > - strncpy(res->name, name, NFP_RESOURCE_ENTRY_NAME_SZ); > + strscpy(res->name, name, sizeof(res->name)); > > dev_mutex = nfp_cpp_mutex_alloc(cpp, NFP_RESOURCE_TBL_TARGET, > NFP_RESOURCE_TBL_BASE, > > --- > base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 > change-id: 20231011-strncpy-drivers-net-ethernet-netronome-nfp-nfpcore-nfp_resource-c-1812b8357fcd > > 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 Wed, 11 Oct 2023 21:48:39 +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 res->name to be NUL-terminated based on its usage with format > strings: > | dev_err(cpp->dev.parent, "Dangling area: %d:%d:%d:0x%0llx-0x%0llx%s%s\n", > | NFP_CPP_ID_TARGET_of(res->cpp_id), > | NFP_CPP_ID_ACTION_of(res->cpp_id), > | NFP_CPP_ID_TOKEN_of(res->cpp_id), > | res->start, res->end, > | res->name ? " " : "", > | res->name ? res->name : ""); > ... and with strcmp() > | if (!strcmp(res->name, NFP_RESOURCE_TBL_NAME)) { > > [...] Here is the summary with links: - nfp: replace deprecated strncpy with strscpy https://git.kernel.org/netdev/net-next/c/d273e99b5623 You are awesome, thank you!
diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c index ce7492a6a98f..279ea0b56955 100644 --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c @@ -159,7 +159,7 @@ nfp_resource_acquire(struct nfp_cpp *cpp, const char *name) if (!res) return ERR_PTR(-ENOMEM); - strncpy(res->name, name, NFP_RESOURCE_ENTRY_NAME_SZ); + strscpy(res->name, name, sizeof(res->name)); dev_mutex = nfp_cpp_mutex_alloc(cpp, NFP_RESOURCE_TBL_TARGET, NFP_RESOURCE_TBL_BASE,
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 res->name to be NUL-terminated based on its usage with format strings: | dev_err(cpp->dev.parent, "Dangling area: %d:%d:%d:0x%0llx-0x%0llx%s%s\n", | NFP_CPP_ID_TARGET_of(res->cpp_id), | NFP_CPP_ID_ACTION_of(res->cpp_id), | NFP_CPP_ID_TOKEN_of(res->cpp_id), | res->start, res->end, | res->name ? " " : "", | res->name ? res->name : ""); ... and with strcmp() | if (!strcmp(res->name, NFP_RESOURCE_TBL_NAME)) { Moreover, NUL-padding is not required as `res` is already zero-allocated: | res = kzalloc(sizeof(*res), 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 opt to use the more idiomatic strscpy() usage of (dest, src, sizeof(dest)) rather than (dest, src, SOME_LEN). Typically the pattern of 1) allocate memory for string, 2) copy string into freshly-allocated memory is a candidate for kmemdup_nul() but in this case we are allocating the entirety of the `res` struct and that should stay as is. As mentioned above, simple 1:1 replacement of strncpy -> 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: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 change-id: 20231011-strncpy-drivers-net-ethernet-netronome-nfp-nfpcore-nfp_resource-c-1812b8357fcd Best regards, -- Justin Stitt <justinstitt@google.com>