diff options
| author | Kees Cook <keescook@chromium.org> | 2012-04-16 11:56:45 -0700 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2012-04-19 13:39:56 +1000 |
| commit | 389da25f93eea8ff64181ae7e3e87da68acaef2e (patch) | |
| tree | 09277860746b3372cbb49ea82868709cbae99ec3 /Documentation/security | |
| parent | 8156b451f37898d3c3652b4e988a4d62ae16eaac (diff) | |
Yama: add additional ptrace scopes
This expands the available Yama ptrace restrictions to include two more
modes. Mode 2 requires CAP_SYS_PTRACE for PTRACE_ATTACH, and mode 3
completely disables PTRACE_ATTACH (and locks the sysctl).
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'Documentation/security')
| -rw-r--r-- | Documentation/security/Yama.txt | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/Documentation/security/Yama.txt b/Documentation/security/Yama.txt index a9511f17906..e369de2d48c 100644 --- a/Documentation/security/Yama.txt +++ b/Documentation/security/Yama.txt @@ -34,7 +34,7 @@ parent to a child process (i.e. direct "gdb EXE" and "strace EXE" still work), or with CAP_SYS_PTRACE (i.e. "gdb --pid=PID", and "strace -p PID" still work as root). -For software that has defined application-specific relationships +In mode 1, software that has defined application-specific relationships between a debugging process and its inferior (crash handlers, etc), prctl(PR_SET_PTRACER, pid, ...) can be used. An inferior can declare which other process (and its descendents) are allowed to call PTRACE_ATTACH @@ -46,6 +46,8 @@ restrictions, it can call prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, ...) so that any otherwise allowed process (even those in external pid namespaces) may attach. +These restrictions do not change how ptrace via PTRACE_TRACEME operates. + The sysctl settings are: 0 - classic ptrace permissions: a process can PTRACE_ATTACH to any other @@ -60,6 +62,12 @@ The sysctl settings are: inferior can call prctl(PR_SET_PTRACER, debugger, ...) to declare an allowed debugger PID to call PTRACE_ATTACH on the inferior. +2 - admin-only attach: only processes with CAP_SYS_PTRACE may use ptrace + with PTRACE_ATTACH. + +3 - no attach: no processes may use ptrace with PTRACE_ATTACH. Once set, + this sysctl cannot be changed to a lower value. + The original children-only logic was based on the restrictions in grsecurity. ============================================================== |