| Message ID | 20240412-strncpy-kernel-module-kallsyms-c-v1-1-ba3f0fc16163@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | kallsyms: replace deprecated strncpy with strscpy | expand |
On Fri, Apr 12, 2024 at 06:53:47PM +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. The goal is to remove its use completely [2]. > > namebuf is eventually cleaned of any trailing llvm suffixes using > strstr(). This hints that namebuf should be NUL-terminated. > > static void cleanup_symbol_name(char *s) > { > char *res; > ... > res = strstr(s, ".llvm."); > ... > } > > Due to this, use strscpy() over strncpy() as it guarantees > NUL-termination on the destination buffer. Drop the -1 from the length > calculation as it is no longer needed to ensure NUL-termination. > > 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 > Link: https://github.com/KSPP/linux/issues/90 [2] > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> Thanks! Queued up on modules-next. Luis
diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c index ef73ae7c8909..62fb57bb9f16 100644 --- a/kernel/module/kallsyms.c +++ b/kernel/module/kallsyms.c @@ -348,7 +348,7 @@ const char *module_address_lookup(unsigned long addr, } /* Make a copy in here where it's safe */ if (ret) { - strncpy(namebuf, ret, KSYM_NAME_LEN - 1); + strscpy(namebuf, ret, KSYM_NAME_LEN); ret = namebuf; } preempt_enable();
strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. The goal is to remove its use completely [2]. namebuf is eventually cleaned of any trailing llvm suffixes using strstr(). This hints that namebuf should be NUL-terminated. static void cleanup_symbol_name(char *s) { char *res; ... res = strstr(s, ".llvm."); ... } Due to this, use strscpy() over strncpy() as it guarantees NUL-termination on the destination buffer. Drop the -1 from the length calculation as it is no longer needed to ensure NUL-termination. 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 Link: https://github.com/KSPP/linux/issues/90 [2] Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- --- kernel/module/kallsyms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: d7ad0581567927c433918bb5f06f3d29f89807d3 change-id: 20240412-strncpy-kernel-module-kallsyms-c-8539c5e7bf57 Best regards, -- Justin Stitt <justinstitt@google.com>