[PATCH] initramfs: fix CPIO hardlink check

Copy the filenames of hardlinks when inserting them into the hash, since
the "name" pointer may point to scratch space (name_buf).  Not doing so
results in corruption if the scratch space is later overwritten: the wrong
file may be hardlinked, or, if the scratch space contains garbage, the link
will fail and a 0-byte file will be created instead.

Signed-off-by: Mark Huang <mlhuang@cs.princeton.edu>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

init/initramfs.c

@@ -26,10 +26,12 @@ static void __init free(void *where)
 
 /* link hash */
 
+#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
+
 static __initdata struct hash {
 	int ino, minor, major;
 	struct hash *next;
-	char *name;
+	char name[N_ALIGN(PATH_MAX)];
 } *head[32];
 
 static inline int hash(int major, int minor, int ino)
@@ -57,7 +59,7 @@ static char __init *find_link(int major, int minor, int ino, char *name)
 	q->ino = ino;
 	q->minor = minor;
 	q->major = major;
-	q->name = name;
+	strcpy(q->name, name);
 	q->next = NULL;
 	*p = q;
 	return NULL;
@@ -133,8 +135,6 @@ static inline void eat(unsigned n)
 	count -= n;
 }
 
-#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
-
 static __initdata char *collected;
 static __initdata int remains;
 static __initdata char *collect;