linux/security
Eric W. Biederman a4ae32c71f exec: Always set cap_ambient in cap_bprm_set_creds
An invariant of cap_bprm_set_creds is that every field in the new cred
structure that cap_bprm_set_creds might set, needs to be set every
time to ensure the fields does not get a stale value.

The field cap_ambient is not set every time cap_bprm_set_creds is
called, which means that if there is a suid or sgid script with an
interpreter that has neither the suid nor the sgid bits set the
interpreter should be able to accept ambient credentials.
Unfortuantely because cap_ambient is not reset to it's original value
the interpreter can not accept ambient credentials.

Given that the ambient capability set is expected to be controlled by
the caller, I don't think this is particularly serious.  But it is
definitely worth fixing so the code works correctly.

I have tested to verify my reading of the code is correct and the
interpreter of a sgid can receive ambient capabilities with this
change and cannot receive ambient capabilities without this change.

Cc: stable@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>
Fixes: 58319057b7 ("capabilities: ambient capabilities")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-05-26 13:11:00 -05:00
..
apparmor .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
bpf bpf: lsm: Initialize the BPF LSM hooks 2020-03-30 01:34:00 +02:00
integrity Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-04-02 14:49:46 -07:00
keys keys: Fix proc_keys_next to increase position index 2020-04-16 10:10:50 -07:00
loadpin proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
lockdown security,lockdown,selinux: implement SELinux lockdown 2019-12-09 17:53:58 -05:00
safesetid security/safesetid: Replace rcu_swap_protected() with rcu_replace_pointer() 2019-10-30 08:45:57 -07:00
selinux selinux/stable-5.7 PR 20200416 2020-04-16 10:45:47 -07:00
smack Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
tomoyo .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
yama proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
commoncap.c exec: Always set cap_ambient in cap_bprm_set_creds 2020-05-26 13:11:00 -05:00
device_cgroup.c device_cgroup: Export devcgroup_check_permission 2019-10-07 15:11:38 -05:00
inode.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
Kconfig bpf: lsm: Initialize the BPF LSM hooks 2020-03-30 01:34:00 +02:00
Kconfig.hardening meminit fix 2019-07-28 12:33:15 -07:00
lsm_audit.c security,lockdown,selinux: implement SELinux lockdown 2019-12-09 17:53:58 -05:00
Makefile bpf: lsm: Initialize the BPF LSM hooks 2020-03-30 01:34:00 +02:00
min_addr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
security.c security: Refactor declaration of LSM hooks 2020-03-30 01:34:00 +02:00