[PATCH] initramfs overwrite fix
This patch ensures that initramfs overwrites work correctly, even when dealing
with device nodes of different types. Furthermore, when replacing a file
which already exists, we must make very certain that we truncate the existing
file.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/init/initramfs.c b/init/initramfs.c
index f81cfa4..d28c109 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -30,6 +30,7 @@
static __initdata struct hash {
int ino, minor, major;
+ mode_t mode;
struct hash *next;
char name[N_ALIGN(PATH_MAX)];
} *head[32];
@@ -41,7 +42,8 @@
return tmp & 31;
}
-static char __init *find_link(int major, int minor, int ino, char *name)
+static char __init *find_link(int major, int minor, int ino,
+ mode_t mode, char *name)
{
struct hash **p, *q;
for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
@@ -51,14 +53,17 @@
continue;
if ((*p)->major != major)
continue;
+ if (((*p)->mode ^ mode) & S_IFMT)
+ continue;
return (*p)->name;
}
q = (struct hash *)malloc(sizeof(struct hash));
if (!q)
panic("can't allocate link hash entry");
- q->ino = ino;
- q->minor = minor;
q->major = major;
+ q->minor = minor;
+ q->ino = ino;
+ q->mode = mode;
strcpy(q->name, name);
q->next = NULL;
*p = q;
@@ -229,13 +234,25 @@
static int __init maybe_link(void)
{
if (nlink >= 2) {
- char *old = find_link(major, minor, ino, collected);
+ char *old = find_link(major, minor, ino, mode, collected);
if (old)
return (sys_link(old, collected) < 0) ? -1 : 1;
}
return 0;
}
+static void __init clean_path(char *path, mode_t mode)
+{
+ struct stat st;
+
+ if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
+ if (S_ISDIR(st.st_mode))
+ sys_rmdir(path);
+ else
+ sys_unlink(path);
+ }
+}
+
static __initdata int wfd;
static int __init do_name(void)
@@ -248,9 +265,15 @@
}
if (dry_run)
return 0;
+ clean_path(collected, mode);
if (S_ISREG(mode)) {
- if (maybe_link() >= 0) {
- wfd = sys_open(collected, O_WRONLY|O_CREAT, mode);
+ int ml = maybe_link();
+ if (ml >= 0) {
+ int openflags = O_WRONLY|O_CREAT;
+ if (ml != 1)
+ openflags |= O_TRUNC;
+ wfd = sys_open(collected, openflags, mode);
+
if (wfd >= 0) {
sys_fchown(wfd, uid, gid);
sys_fchmod(wfd, mode);
@@ -291,6 +314,7 @@
static int __init do_symlink(void)
{
collected[N_ALIGN(name_len) + body_len] = '\0';
+ clean_path(collected, 0);
sys_symlink(collected + N_ALIGN(name_len), collected);
sys_lchown(collected, uid, gid);
state = SkipIt;