bash: Fix CVE-2019-18276
An issue was discovered in disable_priv_mode in shell.c in GNU Bash through 5.0 patch 11.
By default, if Bash is run with its effective UID not equal to its real UID,
it will drop privileges by setting its effective UID to its real UID.
However, it does so incorrectly. On Linux and other systems that support "saved UID" functionality,
the saved UID is not dropped. An attacker with command execution in the shell can use "enable -f" for
runtime loading of a new builtin, which can be a shared object that calls setuid() and therefore
regains privileges. However, binaries running with an effective UID of 0 are unaffected.
Backport the CVE patche from https://github.com/bminor/bash/commit/
951bdaad7a18cc0dc1036bba86b18b90874d39ff to fix CVE-2019-18276
Signed-off-by: Chet Ramey <chet.ramey@case.edu>
Signed-off-by: De Huo <De.Huo@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
