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getname_flags() massage, part 2

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Take the "long name" case into a helper (getname_long()). In
case of failure have the caller deal with freeing the original
struct filename.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2025-11-19 17:28:04 -05:00
parent 8ba29c85e2
commit 8f2ac84817
1 changed files with 29 additions and 27 deletions
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56
fs/namei.c
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@ -131,6 +131,32 @@ static inline void initname(struct filename *name)
atomic_set(&name->refcnt, 1);
}
static struct filename *getname_long(struct filename *old,
const char __user *filename)
{
int len;
/*
* size is chosen that way we to guarantee that
* p->iname[0] is within the same object and that
* p->name can't be equal to p->iname, no matter what.
*/
const size_t size = offsetof(struct filename, iname[1]);
struct filename *p __free(kfree) = kzalloc(size, GFP_KERNEL);
if (unlikely(!p))
return ERR_PTR(-ENOMEM);
memmove(old, &old->iname, EMBEDDED_NAME_MAX);
p->name = (char *)old;
len = strncpy_from_user((char *)old + EMBEDDED_NAME_MAX,
filename + EMBEDDED_NAME_MAX,
PATH_MAX - EMBEDDED_NAME_MAX);
if (unlikely(len < 0))
return ERR_PTR(len);
if (unlikely(len == PATH_MAX - EMBEDDED_NAME_MAX))
return ERR_PTR(-ENAMETOOLONG);
return no_free_ptr(p);
}
struct filename *
getname_flags(const char __user *filename, int flags)
{
@ -173,34 +199,10 @@ getname_flags(const char __user *filename, int flags)
* userland.
*/
if (unlikely(len == EMBEDDED_NAME_MAX)) {
const size_t size = offsetof(struct filename, iname[1]);
struct filename *p;
/*
* size is chosen that way we to guarantee that
* result->iname[0] is within the same object and that
* kname can't be equal to result->iname, no matter what.
*/
p = kzalloc(size, GFP_KERNEL);
if (unlikely(!p)) {
struct filename *p = getname_long(result, filename);
if (IS_ERR(p)) {
__putname(result);
return ERR_PTR(-ENOMEM);
}
memmove(result, &result->iname, EMBEDDED_NAME_MAX);
kname = (char *)result;
p->name = kname;
len = strncpy_from_user(kname + EMBEDDED_NAME_MAX,
filename + EMBEDDED_NAME_MAX,
PATH_MAX - EMBEDDED_NAME_MAX);
if (unlikely(len < 0)) {
kfree(p);
__putname(result);
return ERR_PTR(len);
}
if (unlikely(len == PATH_MAX - EMBEDDED_NAME_MAX)) {
kfree(p);
__putname(result);
return ERR_PTR(-ENAMETOOLONG);
return p;
}
result = p;
}