[bug report] smb: client: do not defer close open handles to deleted files

[bug report] smb: client: do not defer close open handles to deleted files

[Dan Carpenter]

Hello Meetakshi Setiya,

The patch 05211603b73a: "smb: client: do not defer close open handles
to deleted files" from Feb 9, 2024 (linux-next), leads to the
following Smatch static checker warning:

	fs/smb/client/misc.c:871 cifs_mark_open_handles_for_deleted_file()
	error: 'full_path' dereferencing possible ERR_PTR()

fs/smb/client/misc.c
    860 void cifs_mark_open_handles_for_deleted_file(struct cifs_tcon *tcon,
    861                                              const char *path)
    862 {
    863         struct cifsFileInfo *cfile;
    864         void *page;
    865         const char *full_path;
    866 
    867         page = alloc_dentry_path();
    868         spin_lock(&tcon->open_file_lock);
    869         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
    870                 full_path = build_path_from_dentry(cfile->dentry, page);

build_path_from_dentry() can only fail when the name is too long.  I
don't know if that's possible here...

--> 871                 if (strcmp(full_path, path) == 0)
                                   ^^^^^^^^^
This is the dereference Smatch is warning about.  Feel free to ignore
this warning if it's a false positive.  These are one time emails so
it's not a huge stress situation.

    872                         cfile->status_file_deleted = true;
    873         }
    874         spin_unlock(&tcon->open_file_lock);
    875         free_dentry_path(page);
    876 }

regards,
dan carpenter

RE: [EXTERNAL] [bug report] smb: client: do not defer close open handles to deleted files

[Meetakshi Setiya]

Hi Dan,

Thanks for pointing it out. Seems like I did miss an error check for build_path_from_dentry. I will fix this and send the updated patch.

Regards
Meetakshi

-----Original Message-----
From: Dan Carpenter <dan.carpenter@linaro.org> 
Sent: Tuesday, February 27, 2024 8:54 PM
To: Meetakshi Setiya <msetiya@microsoft.com>
Cc: linux-cifs@vger.kernel.org
Subject: [EXTERNAL] [bug report] smb: client: do not defer close open handles to deleted files

[You don't often get email from dan.carpenter@linaro.org. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]

Hello Meetakshi Setiya,

The patch 05211603b73a: "smb: client: do not defer close open handles to deleted files" from Feb 9, 2024 (linux-next), leads to the following Smatch static checker warning:

        fs/smb/client/misc.c:871 cifs_mark_open_handles_for_deleted_file()
        error: 'full_path' dereferencing possible ERR_PTR()

fs/smb/client/misc.c
    860 void cifs_mark_open_handles_for_deleted_file(struct cifs_tcon *tcon,
    861                                              const char *path)
    862 {
    863         struct cifsFileInfo *cfile;
    864         void *page;
    865         const char *full_path;
    866
    867         page = alloc_dentry_path();
    868         spin_lock(&tcon->open_file_lock);
    869         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
    870                 full_path = build_path_from_dentry(cfile->dentry, page);

build_path_from_dentry() can only fail when the name is too long.  I don't know if that's possible here...

--> 871                 if (strcmp(full_path, path) == 0)
                                   ^^^^^^^^^ This is the dereference Smatch is warning about.  Feel free to ignore this warning if it's a false positive.  These are one time emails so it's not a huge stress situation.

    872                         cfile->status_file_deleted = true;
    873         }
    874         spin_unlock(&tcon->open_file_lock);
    875         free_dentry_path(page);
    876 }

regards,
dan carpenter