[pve-devel] [PATCH storage v2] fix #5181: pbs: store and read passwords as unicode

[Maximiliano Sandoval]

At the moment calling
```
pvesm add pbs test --password="bär12345" --datastore='test' # ..other params
```

Will result in the API handler getting the param->{passowrd} as a utf-8
encoded string. When dumped with Debug::Peek's Dump() one can see:

```
SV = PV(0x5a02c1a3ff10) at 0x5a02bd713670
  REFCNT = 1
  FLAGS = (POK,IsCOW,pPOK,UTF8)
  PV = 0x5a02c1a409b0 "b\xC3\xA4r12345"\0 [UTF8 "b\x{e4}r12345"]
  CUR = 9
  LEN = 11
  COW_REFCNT = 0
```

Then when writing the file via file_set_contents (using syswrite
internally) will result in perl encoding the password as latin1 and a
file with contents:

```
$ hexdump -C /etc/pve/priv/storage/test.pw
00000000  62 e4 72 31 32 33 34 35                           |b.r12345|
00000008
```

when the correct contents should have been:
```
00000000  62 c3 a4 72 31 32 33 34  35                       |b..r12345|
00000009
```

Later when the file is read via file_read_firstline it will result in

```
SV = PV(0x5e8baa411090) at 0x5e8baa5a96b8
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x5e8baa43ee20 "b\xE4r12345"\0
  CUR = 8
  LEN = 81
```

which is a different string than the original.

At the moment, adding the storage will work as the utf8 password is
still in memory, however, however subsequent uses (e.g. pvestatd) will
fail.

This patch fixes the issue by encoding the string as utf8 both when
reading and storing it to disk. The user was able in the past to go
around the issue by writing the right password in
/etc/pve/priv/{storage}.pw and this fix is compatible with that.

It is documented at
https://pbs.proxmox.com/docs/backup-client.html#environment-variables
that the Backup Server password must be valid utf-8.

Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
---
 src/PVE/Storage/PBSPlugin.pm | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/PVE/Storage/PBSPlugin.pm b/src/PVE/Storage/PBSPlugin.pm
index 00170f5a..59f5fcc5 100644
--- a/src/PVE/Storage/PBSPlugin.pm
+++ b/src/PVE/Storage/PBSPlugin.pm
@@ -5,6 +5,7 @@ package PVE::Storage::PBSPlugin;
 use strict;
 use warnings;
 
+use Encode qw(decode);
 use Fcntl qw(F_GETFD F_SETFD FD_CLOEXEC);
 use IO::File;
 use JSON;
@@ -93,7 +94,7 @@ sub pbs_set_password {
     my $pwfile = pbs_password_file_name($scfg, $storeid);
     mkdir "/etc/pve/priv/storage";
 
-    PVE::Tools::file_set_contents($pwfile, "$password\n");
+    PVE::Tools::file_set_contents($pwfile, "$password\n", undef, 1);
 }
 
 sub pbs_delete_password {
@@ -109,7 +110,9 @@ sub pbs_get_password {
 
     my $pwfile = pbs_password_file_name($scfg, $storeid);
 
-    return PVE::Tools::file_read_firstline($pwfile);
+    my $contents = PVE::Tools::file_read_firstline($pwfile);
+
+    return eval { decode('UTF-8', $contents, 1) } // $contents;
 }
 
 sub pbs_encryption_key_file_name {
-- 
2.39.5