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| author | Andy Lutomirski | 2012-04-12 23:47:50 +0200 |
|---|---|---|
| committer | James Morris | 2012-04-14 03:13:18 +0200 |
| commit | 259e5e6c75a910f3b5e656151dc602f53f9d7548 (patch) | |
| tree | 4405fdf68238f2e33f27b04e8c37c9e29a2493d8 /include/linux/security.h | |
| parent | maintainers: update wiki url for the security subsystem (diff) | |
| download | kernel-qcow2-linux-259e5e6c75a910f3b5e656151dc602f53f9d7548.tar.gz kernel-qcow2-linux-259e5e6c75a910f3b5e656151dc602f53f9d7548.tar.xz kernel-qcow2-linux-259e5e6c75a910f3b5e656151dc602f53f9d7548.zip | |
Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs
With this change, calling
prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
disables privilege granting operations at execve-time. For example, a
process will not be able to execute a setuid binary to change their uid
or gid if this bit is set. The same is true for file capabilities.
Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that
LSMs respect the requested behavior.
To determine if the NO_NEW_PRIVS bit is set, a task may call
prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
It returns 1 if set and 0 if it is not set. If any of the arguments are
non-zero, it will return -1 and set errno to -EINVAL.
(PR_SET_NO_NEW_PRIVS behaves similarly.)
This functionality is desired for the proposed seccomp filter patch
series. By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the
system call behavior for itself and its child tasks without being
able to impact the behavior of a more privileged task.
Another potential use is making certain privileged operations
unprivileged. For example, chroot may be considered "safe" if it cannot
affect privileged tasks.
Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is
set and AppArmor is in use. It is fixed in a subsequent patch.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'include/linux/security.h')
| -rw-r--r-- | include/linux/security.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/security.h b/include/linux/security.h index 673afbb8238a..6e1dea93907a 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -144,6 +144,7 @@ struct request_sock; #define LSM_UNSAFE_SHARE 1 #define LSM_UNSAFE_PTRACE 2 #define LSM_UNSAFE_PTRACE_CAP 4 +#define LSM_UNSAFE_NO_NEW_PRIVS 8 #ifdef CONFIG_MMU extern int mmap_min_addr_handler(struct ctl_table *table, int write, |