Jeremy Allison
2020-Dec-01 21:45 UTC
[Samba] Strange logs: check_usershare_stat: file /var/lib/samba/usershares/ owned by uid 0 is not a regular file
On Tue, Dec 01, 2020 at 01:29:55PM -0800, Jeremy Allison via samba wrote:>On Tue, Dec 01, 2020 at 08:10:52PM -0000, Roy Eastwood via samba wrote: >>Thanks Andrew for your quick reply. >> >>Here are the results of those commands: >> >>root at lxd-m1:~# ls -l /var/lib/samba/usershares >>total 0 >>root at lxd-m1:~# ls -l /var/lib/samba/ >>total 136 >>-rw------- 1 root root 421888 Jun 16 19:18 account_policy.tdb >>drwxr-xr-x 1 root root 36 Jul 19 2019 DriverStore >>-rw------- 1 root root 425984 Jul 19 2019 group_mapping.tdb >>drwxr-xr-x 1 root root 98 Jul 19 2019 printers >>drwxr-xr-x 1 root root 124 Jul 19 2019 private >>-rw------- 1 root root 528384 Jul 19 2019 registry.tdb >>-rw------- 1 root root 421888 Jul 21 2019 share_info.tdb >>drwxrwx--T 1 root sambashare 0 Jul 19 2019 usershares >>-rw------- 1 root root 32768 Dec 1 19:57 winbindd_cache.tdb >>-rw-r--r-- 1 root root 421888 Jul 20 2019 winbindd_idmap.tdb >>drwxr-x--- 1 root winbindd_priv 8 Nov 4 17:08 winbindd_privileged >>root at lxd-m1:~# stat /var/lib/samba/usershares >> File: /var/lib/samba/usershares >> Size: 0 Blocks: 0 IO Block: 4096 directory >>Device: 41h/65d Inode: 24656 Links: 1 >>Access: (1770/drwxrwx--T) Uid: ( 0/ root) Gid: ( 111/sambashare) >>Access: 2020-12-01 19:00:10.120922818 +0000 >>Modify: 2019-07-19 12:14:08.718571118 +0100 >>Change: 2020-01-17 09:43:21.506782092 +0000 >>Birth: - >>root at lxd-m1:~# > >This is triggered by this code: > > if (!S_ISREG(psbuf->st_ex_mode)) { > DEBUG(0,("check_usershare_stat: file %s owned by uid %u is " > "not a regular file\n", > fname, (unsigned int)psbuf->st_ex_uid )); > return false; > } > >but it should be looking at the files inside /var/lib/samba/usershares, >not the /var/lib/samba/usershares directory itself. > >This is called from load_usershare_service(), which is passed >the name of the share to find as a usershare. It looks like >this is being passed an empty "" string.Here is the code that is processing the usersharepath: In your case - usersharepath = "/var/lib/samba/usershares". As you can see below (error return processing removed for clarity), it's passing the return from readdir(dp)->d_name to the process_usershare_file() code that calls check_usershare_stat(). dp = opendir(usersharepath); for (num_dir_entries = 0, num_bad_dir_entries = 0, num_tmp_dir_entries = 0; (de = readdir(dp)); num_dir_entries++ ) { int r; const char *n = de->d_name; /* Ignore . and .. */ if (*n == '.') { if ((n[1] == '\0') || (n[1] == '.' && n[2] == '\0')) { continue; } } if (n[0] == ':') { /* Temporary file used when creating a share. */ num_tmp_dir_entries++; } r = process_usershare_file(usersharepath, n, snum_template); If n=="" here, then we'd get (error processing removed): static int process_usershare_file(const char *dir_name, const char *file_name, int snum_template) { ... /* Ensure share name doesn't contain invalid characters. */ if (!validate_net_name(file_name, INVALID_SHARENAME_CHARS, strlen(file_name))) { ... goto out; } canon_name = canonicalize_servicename(ctx, file_name); fname = talloc_asprintf(ctx, "%s/%s", dir_name, file_name); /* Minimize the race condition by doing an lstat before we open and fstat. Ensure this isn't a symlink link. */ if (sys_lstat(fname, &lsbuf, false) != 0) { goto out; } /* This must be a regular file, not a symlink, directory or other strange filetype. */ if (!check_usershare_stat(fname, &lsbuf)) { ... n="", fname = "/var/lib/samba/usershares/" and you'd get the results you see. Can you add some debugging inside the directory enumeration code to see what you're getting back from the readdir() ?
Rowland penny
2020-Dec-01 22:08 UTC
[Samba] Strange logs: check_usershare_stat: file /var/lib/samba/usershares/ owned by uid 0 is not a regular file
On 01/12/2020 21:45, Jeremy Allison via samba wrote:> On Tue, Dec 01, 2020 at 01:29:55PM -0800, Jeremy Allison via samba wrote: >> On Tue, Dec 01, 2020 at 08:10:52PM -0000, Roy Eastwood via samba wrote: >>> Thanks Andrew for your quick reply. >>> >>> Here are the results of those commands: >>> >>> root at lxd-m1:~# ls -l /var/lib/samba/usershares >>> total 0 >>> root at lxd-m1:~# ls -l /var/lib/samba/ >>> total 136 >>> -rw------- 1 root root????????? 421888 Jun 16 19:18 account_policy.tdb >>> drwxr-xr-x 1 root root????????????? 36 Jul 19? 2019 DriverStore >>> -rw------- 1 root root????????? 425984 Jul 19? 2019 group_mapping.tdb >>> drwxr-xr-x 1 root root????????????? 98 Jul 19? 2019 printers >>> drwxr-xr-x 1 root root???????????? 124 Jul 19? 2019 private >>> -rw------- 1 root root????????? 528384 Jul 19? 2019 registry.tdb >>> -rw------- 1 root root????????? 421888 Jul 21? 2019 share_info.tdb >>> drwxrwx--T 1 root sambashare???????? 0 Jul 19? 2019 usershares >>> -rw------- 1 root root?????????? 32768 Dec? 1 19:57 winbindd_cache.tdb >>> -rw-r--r-- 1 root root????????? 421888 Jul 20? 2019 winbindd_idmap.tdb >>> drwxr-x--- 1 root winbindd_priv????? 8 Nov? 4 17:08 winbindd_privileged >>> root at lxd-m1:~# stat? /var/lib/samba/usershares >>> File: /var/lib/samba/usershares >>> Size: 0?????????????? Blocks: 0????????? IO Block: 4096 directory >>> Device: 41h/65d Inode: 24656?????? Links: 1 >>> Access: (1770/drwxrwx--T)? Uid: (??? 0/??? root)?? Gid: ( >>> 111/sambashare) >>> Access: 2020-12-01 19:00:10.120922818 +0000 >>> Modify: 2019-07-19 12:14:08.718571118 +0100 >>> Change: 2020-01-17 09:43:21.506782092 +0000 >>> Birth: - >>> root at lxd-m1:~# >> >> This is triggered by this code: >> >> ?????? if (!S_ISREG(psbuf->st_ex_mode)) { >> ?????????????? DEBUG(0,("check_usershare_stat: file %s owned by uid >> %u is " >> ?????????????????????? "not a regular file\n", >> ?????????????????????? fname, (unsigned int)psbuf->st_ex_uid )); >> ?????????????? return false; >> ?????? } >> >> but it should be looking at the files inside /var/lib/samba/usershares, >> not the /var/lib/samba/usershares directory itself. >> >> This is called from load_usershare_service(), which is passed >> the name of the share to find as a usershare. It looks like >> this is being passed an empty "" string. > > Here is the code that is processing the usersharepath: > > In your case - usersharepath = "/var/lib/samba/usershares". > > As you can see below (error return processing removed for > clarity), it's passing the return from readdir(dp)->d_name > to the process_usershare_file() code that calls check_usershare_stat(). > > ??????? dp = opendir(usersharepath); > ??????? for (num_dir_entries = 0, num_bad_dir_entries = 0, > num_tmp_dir_entries = 0; > ??????????????????????? (de = readdir(dp)); > ??????????????????????? num_dir_entries++ ) { > ??????????????? int r; > ??????????????? const char *n = de->d_name; > > ??????????????? /* Ignore . and .. */ > ??????????????? if (*n == '.') { > ??????????????????????? if ((n[1] == '\0') || (n[1] == '.' && n[2] == > '\0')) { > ??????????????????????????????? continue; > ??????????????????????? } > ??????????????? } > > ??????????????? if (n[0] == ':') { > ??????????????????????? /* Temporary file used when creating a share. */ > ??????????????????????? num_tmp_dir_entries++; > ??????????????? } > > ??????????????? r = process_usershare_file(usersharepath, n, > snum_template); > > If n=="" here, then we'd get (error processing removed): > > static int process_usershare_file(const char *dir_name, const char > *file_name, int snum_template) > { > ... > ?????? /* Ensure share name doesn't contain invalid characters. */ > ??????? if (!validate_net_name(file_name, INVALID_SHARENAME_CHARS, > strlen(file_name))) { > ??????? ... > ??????????????? goto out; > ??????? } > > ??????? canon_name = canonicalize_servicename(ctx, file_name); > ??????? fname = talloc_asprintf(ctx, "%s/%s", dir_name, file_name); > > ??????? /* Minimize the race condition by doing an lstat before we > ?????????? open and fstat. Ensure this isn't a symlink link. */ > > ??????? if (sys_lstat(fname, &lsbuf, false) != 0) { > ??????????????? goto out; > ??????? } > > ??????? /* This must be a regular file, not a symlink, directory or > ?????????? other strange filetype. */ > ??????? if (!check_usershare_stat(fname, &lsbuf)) { > ... > > n="", fname = "/var/lib/samba/usershares/" and you'd get the results > you see. > > Can you add some debugging inside the directory enumeration > code to see what you're getting back from the readdir() ? >could this have anything to do with it: 4.12.0 Default: usershare max shares = 0 4.13.2 Default: usershare max shares = 100 Rowland