Buffer for directory headers history was too small. This can be
exploitable by some attacker capable of controlling backup stream, but
it isn't any security problem. We don't assume this part of backup
system to be trusted, the attacker can at most prevent user from
restoring some data, but will neither gain access to them, or compromise
any other Qubes component. This is equivalent to bug in any other tool
used in backup vm (like FTP client) and the Qubes backup system is
designed specifically to minimize impact of such bugs.
read() syscall do not guarantee to read as much data as requested. This
is especially important when reading from pipe - remote end can produce
data slower than we are reading them. Use read_all() helper to always
get requested amount of data.
Assume that all the files of directory are in continuous block (which is
true in case of qvm-backup stream). This will allow to terminate before
getting to the file end - especially useful when only qubes.xml
requested.
Actually one was real bug:
- current = ustar_rd(fd, &hdr, &buf, &sb);
+ current = ustar_rd(fd, &hdr, buf, &sb);
The others was mostly invalid printf format string.
