From: Eric Biggers <ebiggers3@gmail.com>
Date: Thu, 5 Nov 2015 02:43:27 +0000 (-0600)
Subject: Avoid passing NULL as memcpy source (undefined behavior)
X-Git-Tag: v1.8.3~15
X-Git-Url: https://wimlib.net/git/?p=wimlib;a=commitdiff_plain;h=564aacbad3801ec37c2455e15b9296ecaef4eb93;hp=8fbdced08faf37472fd7174480b446c4b11578fb;ds=sidebyside

Avoid passing NULL as memcpy source (undefined behavior)
---

diff --git a/src/dentry.c b/src/dentry.c
index ff1a2142..caa3a51b 100644
--- a/src/dentry.c
+++ b/src/dentry.c
@@ -504,7 +504,8 @@ calculate_dentry_full_path(struct wim_dentry *dentry)
 	d = dentry;
 	do {
 		p -= d->d_name_nbytes / sizeof(utf16lechar);
-		memcpy(p, d->d_name, d->d_name_nbytes);
+		if (d->d_name_nbytes)
+			memcpy(p, d->d_name, d->d_name_nbytes);
 		*--p = cpu_to_le16(WIM_PATH_SEPARATOR);
 		d = d->d_parent;  /* assumes d == d->d_parent for root  */
 	} while (!dentry_is_root(d));
diff --git a/src/unix_apply.c b/src/unix_apply.c
index f1962d98..ae9b8cea 100644
--- a/src/unix_apply.c
+++ b/src/unix_apply.c
@@ -156,7 +156,9 @@ unix_build_extraction_path(const struct wim_dentry *dentry,
 	d = dentry;
 	do {
 		p -= d->d_extraction_name_nchars;
-		memcpy(p, d->d_extraction_name, d->d_extraction_name_nchars);
+		if (d->d_extraction_name_nchars)
+			memcpy(p, d->d_extraction_name,
+			       d->d_extraction_name_nchars);
 		*--p = '/';
 		d = d->d_parent;
 	} while (!dentry_is_root(d) && will_extract_dentry(d));
diff --git a/src/win32_apply.c b/src/win32_apply.c
index c31d2668..cb488a9f 100644
--- a/src/win32_apply.c
+++ b/src/win32_apply.c
@@ -901,7 +901,9 @@ build_extraction_path(const struct wim_dentry *dentry,
 	     d = d->d_parent)
 	{
 		p -= d->d_extraction_name_nchars;
-		wmemcpy(p, d->d_extraction_name, d->d_extraction_name_nchars);
+		if (d->d_extraction_name_nchars)
+			wmemcpy(p, d->d_extraction_name,
+				d->d_extraction_name_nchars);
 		*--p = '\\';
 	}
 	/* No leading slash  */