Messages in this thread Patch in this message | | | Date | Wed, 11 Oct 2023 21:48:39 +0000 | Subject | [PATCH] nfp: replace deprecated strncpy with strscpy | From | Justin Stitt <> |
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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)); 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>
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