2021-09-01 17:54:22

by Stephen Brennan

Subject: [PATCH 3/3] namei: Standardize callers of filename_create()

filename_create() has two variants, one which drops the caller's
reference to filename (filename_create) and one which does
not (__filename_create). This can be confusing as it's unusual to drop a
caller's reference. Remove filename_create, rename __filename_create
to filename_create, and convert all callers.

Link: https://lore.kernel.org/linux-fsdevel/[email protected]/
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Stephen Brennan <[email protected]>
---
fs/namei.c | 38 ++++++++++++++++++++------------------
1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 76871b7f127a..ec76f533ee3e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3622,8 +3622,8 @@ struct file *do_file_open_root(const struct path *root,
return file;
}

-static struct dentry *__filename_create(int dfd, struct filename *name,
- struct path *path, unsigned int lookup_flags)
+static struct dentry *filename_create(int dfd, struct filename *name,
+ struct path *path, unsigned int lookup_flags)
{
struct dentry *dentry = ERR_PTR(-EEXIST);
struct qstr last;
@@ -3691,20 +3691,16 @@ static struct dentry *__filename_create(int dfd, struct filename *name,
return dentry;
}

-static inline struct dentry *filename_create(int dfd, struct filename *name,
- struct path *path, unsigned int lookup_flags)
-{
- struct dentry *res = __filename_create(dfd, name, path, lookup_flags);
-
- putname(name);
- return res;
-}
-
struct dentry *kern_path_create(int dfd, const char *pathname,
struct path *path, unsigned int lookup_flags)
{
- return filename_create(dfd, getname_kernel(pathname),
- path, lookup_flags);
+ struct filename *filename;
+ struct dentry *dentry;
+
+ filename = getname_kernel(pathname);
+ dentry = filename_create(dfd, filename, path, lookup_flags);
+ putname(filename);
+ return dentry;
}
EXPORT_SYMBOL(kern_path_create);

@@ -3720,7 +3716,13 @@ EXPORT_SYMBOL(done_path_create);
inline struct dentry *user_path_create(int dfd, const char __user *pathname,
struct path *path, unsigned int lookup_flags)
{
- return filename_create(dfd, getname(pathname), path, lookup_flags);
+ struct filename *filename;
+ struct dentry *dentry;
+
+ filename = getname(pathname);
+ dentry = filename_create(dfd, getname(pathname), path, lookup_flags);
+ putname(filename);
+ return dentry;
}
EXPORT_SYMBOL(user_path_create);

@@ -3801,7 +3803,7 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
if (error)
goto out1;
retry:
- dentry = __filename_create(dfd, name, &path, lookup_flags);
+ dentry = filename_create(dfd, name, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out1;
@@ -3901,7 +3903,7 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode)
unsigned int lookup_flags = LOOKUP_DIRECTORY;

retry:
- dentry = __filename_create(dfd, name, &path, lookup_flags);
+ dentry = filename_create(dfd, name, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_putname;
@@ -4268,7 +4270,7 @@ int do_symlinkat(struct filename *from, int newdfd, struct filename *to)
goto out_putnames;
}
retry:
- dentry = __filename_create(newdfd, to, &path, lookup_flags);
+ dentry = filename_create(newdfd, to, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_putnames;
@@ -4432,7 +4434,7 @@ int do_linkat(int olddfd, struct filename *old, int newdfd,
if (error)
goto out_putnames;

- new_dentry = __filename_create(newdfd, new, &new_path,
+ new_dentry = filename_create(newdfd, new, &new_path,
(how & LOOKUP_REVAL));
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
--
2.30.2

2021-09-07 20:20:23

by Al Viro

Subject: Re: [PATCH 3/3] namei: Standardize callers of filename_create()

On Wed, Sep 01, 2021 at 10:51:43AM -0700, Stephen Brennan wrote:
> inline struct dentry *user_path_create(int dfd, const char __user *pathname,
> struct path *path, unsigned int lookup_flags)
> {
> - return filename_create(dfd, getname(pathname), path, lookup_flags);
> + struct filename *filename;
> + struct dentry *dentry;
> +
> + filename = getname(pathname);
> + dentry = filename_create(dfd, getname(pathname), path, lookup_flags);
> + putname(filename);
> + return dentry;

Leaks, obviously...

2021-09-07 20:54:29

by Stephen Brennan

Subject: Re: [PATCH 3/3] namei: Standardize callers of filename_create()

On 9/7/21 1:13 PM, Al Viro wrote:
> On Wed, Sep 01, 2021 at 10:51:43AM -0700, Stephen Brennan wrote:
>> inline struct dentry *user_path_create(int dfd, const char __user *pathname,
>> struct path *path, unsigned int lookup_flags)
>> {
>> - return filename_create(dfd, getname(pathname), path, lookup_flags);
>> + struct filename *filename;
>> + struct dentry *dentry;
>> +
>> + filename = getname(pathname);
>> + dentry = filename_create(dfd, getname(pathname), path, lookup_flags);
>> + putname(filename);
>> + return dentry;
>
> Leaks, obviously...
>

Ouch, thanks for the catch. I'll send v2 shortly.