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Commit 2139a7fb authored by H. Peter Anvin's avatar H. Peter Anvin Committed by Linus Torvalds
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[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: default avatarH. Peter Anvin <hpa@zytor.com>
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 05381954

init/initramfs.c

+30 −6
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ static void __init free(void *where) 


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 @@ static inline int hash(int major, int minor, int ino) 
	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 @@ static char __init *find_link(int major, int minor, int ino, char *name) 
			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 do_reset(void) 
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 @@ static int __init do_name(void) 
	}

	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_copy(void) 
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;