From: Justin Stitt <justinstitt@google.com>
Date: Mon, 18 Sep 2023 05:30:15 +0000 (+0000)
Subject: accessibility: speakup: refactor deprecated strncpy
X-Git-Tag: v6.7-rc1~78^2~60
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=19e3e6cdfdc73400eb68d1102cdbad4f9493f474;p=thirdparty%2Fkernel%2Flinux.git

accessibility: speakup: refactor deprecated strncpy

`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 <justinstitt@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Link: https://lore.kernel.org/r/20230918-strncpy-drivers-accessibility-speakup-kobjects-c-v2-1-d5b1976c5dbf@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/accessibility/speakup/kobjects.c b/drivers/accessibility/speakup/kobjects.c
index a7522d4098025..0dfdb6608e022 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;
 }