tar: CVE-2022-48303

Fixes CVE-2022-48303 by checking Base-256 encoding is at least
2 bytes long. GNU Tar through 1.34 has a one-byte out-of-bounds
read that results in use of uninitialized memory for a conditional
jump. Exploitation to change the flow of control has not been
demonstrated. The issue occurs in from_header in list.c via a
V7 archive in which mtime has approximately 11 whitespace characters.

Reference:
https://nvd.nist.gov/vuln/detail/CVE-2022-48303

Upstream patch:
https://savannah.gnu.org/bugs/?62387
https://git.savannah.gnu.org/cgit/tar.git/patch/src/list.c?id=3da78400eafcccb97e2f2fd4b227ea40d794ede8



Signed-off-by: Rodolfo Quesada Zumbado <rodolfo.zumbado@windriver.com>
Signed-off-by: Joe Slater <joe.slater@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>