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[PATCH] initramfs overwrite fix

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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>
This commit is contained in:
H. Peter Anvin 2006-06-26 00:28:02 -07:00 committed by Linus Torvalds
parent 0538195424
commit 2139a7fbf3
1 changed files with 30 additions and 6 deletions
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36
init/initramfs.c
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@ -30,6 +30,7 @@ static void __init free(void *where)
static __initdata struct hash { static __initdata struct hash {
int ino, minor, major; int ino, minor, major;
mode_t mode;
struct hash *next; struct hash *next;
char name[N_ALIGN(PATH_MAX)]; char name[N_ALIGN(PATH_MAX)];
} *head[32]; } *head[32];
@ -41,7 +42,8 @@ static inline int hash(int major, int minor, int ino)
return tmp & 31; 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; struct hash **p, *q;
for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) { 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; continue;
if ((*p)->major != major) if ((*p)->major != major)
continue; continue;
if (((*p)->mode ^ mode) & S_IFMT)
continue;
return (*p)->name; return (*p)->name;
} }
q = (struct hash *)malloc(sizeof(struct hash)); q = (struct hash *)malloc(sizeof(struct hash));
if (!q) if (!q)
panic("can't allocate link hash entry"); panic("can't allocate link hash entry");
q->ino = ino;
q->minor = minor;
q->major = major; q->major = major;
q->minor = minor;
q->ino = ino;
q->mode = mode;
strcpy(q->name, name); strcpy(q->name, name);
q->next = NULL; q->next = NULL;
*p = q; *p = q;
@ -229,13 +234,25 @@ static int __init do_reset(void)
static int __init maybe_link(void) static int __init maybe_link(void)
{ {
if (nlink >= 2) { if (nlink >= 2) {
char *old = find_link(major, minor, ino, collected); char *old = find_link(major, minor, ino, mode, collected);
if (old) if (old)
return (sys_link(old, collected) < 0) ? -1 : 1; return (sys_link(old, collected) < 0) ? -1 : 1;
} }
return 0; 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 __initdata int wfd;
static int __init do_name(void) static int __init do_name(void)
@ -248,9 +265,15 @@ static int __init do_name(void)
} }
if (dry_run) if (dry_run)
return 0; return 0;
clean_path(collected, mode);
if (S_ISREG(mode)) { if (S_ISREG(mode)) {
if (maybe_link() >= 0) { int ml = maybe_link();
wfd = sys_open(collected, O_WRONLY|O_CREAT, mode); if (ml >= 0) {
int openflags = O_WRONLY|O_CREAT;
if (ml != 1)
openflags |= O_TRUNC;
wfd = sys_open(collected, openflags, mode);
if (wfd >= 0) { if (wfd >= 0) {
sys_fchown(wfd, uid, gid); sys_fchown(wfd, uid, gid);
sys_fchmod(wfd, mode); sys_fchmod(wfd, mode);
@ -291,6 +314,7 @@ static int __init do_copy(void)
static int __init do_symlink(void) static int __init do_symlink(void)
{ {
collected[N_ALIGN(name_len) + body_len] = '\0'; collected[N_ALIGN(name_len) + body_len] = '\0';
clean_path(collected, 0);
sys_symlink(collected + N_ALIGN(name_len), collected); sys_symlink(collected + N_ALIGN(name_len), collected);
sys_lchown(collected, uid, gid); sys_lchown(collected, uid, gid);
state = SkipIt; state = SkipIt;