[PATCH next] afs_lookup_atsys(): Use memcpy() instead of strcpy()

[david.laight.linux@gmail.com]

From: David Laight <david.laight.linux@gmail.com>

strlen() has been called to validate the length, use the same length
to copy the string.

Signed-off-by: David Laight <david.laight.linux@gmail.com>
---
This is one of a group of patches that remove potentially unbounded
strcpy() calls.

They are mostly replaced by strscpy() or, when strlen() has just been
called, with memcpy() (usually including the '\0').

Calls with copy string literals into arrays are left unchanged.
They are safe and easily detected as such.

The changes were made by getting the compiler to detect the calls and
then fixing the code by hand.

Note that all the changes are only compile tested.

Some Makefiles were changed to allow files to contain strcpy().
As well as 'difficult to fix' files, this included 'show' functions
as they really need to use sysfs_emit() or seq_printf().

All the patches are being sent individually to avoid very long cc lists.
Apologies for the terse commit messages and likely unexpected tags.
(There are about 100 patches in total.)

 fs/afs/dir.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index aaaa55878ffd..41aa6a4b0987 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -914,7 +914,7 @@ static struct dentry *afs_lookup_atsys(struct inode *dir, struct dentry *dentry)
 	struct afs_net *net = afs_i2net(dir);
 	struct dentry *ret;
 	char *buf, *p, *name;
-	int len, i;
+	int name_len, len, i;
 
 	_enter("");
 
@@ -935,13 +935,14 @@ static struct dentry *afs_lookup_atsys(struct inode *dir, struct dentry *dentry)
 
 	for (i = 0; i < subs->nr; i++) {
 		name = subs->subs[i];
-		len = dentry->d_name.len - 4 + strlen(name);
+		name_len = strlen(name);
+		len = dentry->d_name.len - 4 + name_len;
 		if (len >= AFSNAMEMAX) {
 			ret = ERR_PTR(-ENAMETOOLONG);
 			goto out_s;
 		}
 
-		strcpy(p, name);
+		memcpy(p, name, name_len + 1);
 		ret = lookup_noperm(&QSTR(buf), dentry->d_parent);
 		if (IS_ERR(ret) || d_is_positive(ret))
 			goto out_s;
-- 
2.39.5