soc: qcom: cmd-db: replace deprecated strncpy with strtomem

strncpy() is an ambiguous and potentially dangerous interface [1]. We
should prefer more robust and less ambiguous alternatives.

@query is marked as __nonstring and doesn't need to be NUL-terminated.

Since we are doing a string to memory copy, we can use the aptly named
"strtomem" -- specifically, the "pad" variant to also ensure NUL-padding
throughout the destination buffer.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240319-strncpy-drivers-soc-qcom-cmd-db-c-v3-1-aeb5c5180c32@google.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c
index b4e613c34a5c27d31941303ec215055679e2feb0..d8457266201758dd3d92e3f68df7b81640d30baa 100644 (file)
--- a/drivers/soc/qcom/cmd-db.c
+++ b/drivers/soc/qcom/cmd-db.c
@@ -153,12 +153,7 @@ static int cmd_db_get_header(const char *id, const struct entry_header **eh,
        if (ret)
                return ret;
 
-       /*
-        * Pad out query string to same length as in DB. NOTE: the output
-        * query string is not necessarily '\0' terminated if it bumps up
-        * against the max size. That's OK and expected.
-        */
-       strncpy(query, id, sizeof(query));
+       strtomem_pad(query, id, 0);
 
        for (i = 0; i < MAX_SLV_ID; i++) {
                rsc_hdr = &cmd_db_header->header[i];