`strncpy` is deprecated for use on NUL-terminated destination strings [1]. Let's refactor this function to just use synth_write().
Link: 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 <justinst...@google.com> Suggested-by: Kees Cook <keesc...@chromium.org> Reviewed-by: Kees Cook <keesc...@chromium.org> Tested-by: Samuel Thibault <samuel.thiba...@ens-lyon.org> --- Changes from v1 -> v2: - refactor synth_direct_store (thanks Kees) - rebase onto 3669558bdf354cd352be955ef2764cde6a9bf5ec - Link to v1: https://lore.kernel.org/all/20230824-strncpy-drivers-accessibility-speakup-kobjects-c-v1-1-3a1ef1221...@google.com/ --- drivers/accessibility/speakup/kobjects.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/drivers/accessibility/speakup/kobjects.c b/drivers/accessibility/speakup/kobjects.c index a7522d409802..0dfdb6608e02 100644 --- a/drivers/accessibility/speakup/kobjects.c +++ b/drivers/accessibility/speakup/kobjects.c @@ -413,27 +413,24 @@ static ssize_t synth_direct_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { - u_char tmp[256]; - int len; - int bytes; - const char *ptr = buf; + char *unescaped; unsigned long flags; if (!synth) return -EPERM; - len = strlen(buf); + unescaped = kstrdup(buf, GFP_KERNEL); + if (!unescaped) + return -ENOMEM; + + string_unescape_any_inplace(unescaped); + spin_lock_irqsave(&speakup_info.spinlock, flags); - while (len > 0) { - bytes = min_t(size_t, len, 250); - strncpy(tmp, ptr, bytes); - tmp[bytes] = '\0'; - string_unescape_any_inplace(tmp); - synth_printf("%s", tmp); - ptr += bytes; - len -= bytes; - } + synth_write(unescaped, strlen(unescaped)); spin_unlock_irqrestore(&speakup_info.spinlock, flags); + + kfree(unescaped); + return count; } --- base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec change-id: 20230824-strncpy-drivers-accessibility-speakup-kobjects-c-4009e7df0936 Best regards, -- Justin Stitt <justinst...@google.com>
