proc: report no_new_privs state

Similar to being able to examine if a process has been correctly
confined with seccomp, the state of no_new_privs is equally interesting,
so this adds it to /proc/$pid/status.

Link: http://lkml.kernel.org/r/20161103214041.GA58566@beast
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Jann Horn <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Rodrigo Freire <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Robert Ho <[email protected]>
Cc: Jerome Marchand <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: "Richard W.M. Jones" <[email protected]>
Cc: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 74329fd0add2237a848a72fb71a46d5e4e98cee4..c03f2f91c6aba59659ec0dc6e8396e99336934a6 100644 (file)
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -191,6 +191,7 @@ read the file /proc/PID/status:
   CapPrm: 0000000000000000
   CapEff: 0000000000000000
   CapBnd: ffffffffffffffff
+  NoNewPrivs:     0
   Seccomp:        0
   voluntary_ctxt_switches:        0
   nonvoluntary_ctxt_switches:     1
@@ -262,6 +263,7 @@ Table 1-2: Contents of the status files (as of 4.1)
  CapPrm                      bitmap of permitted capabilities
  CapEff                      bitmap of effective capabilities
  CapBnd                      bitmap of capabilities bounding set
+ NoNewPrivs                  no_new_privs, like prctl(PR_GET_NO_NEW_PRIV, ...)
  Seccomp                     seccomp mode, like prctl(PR_GET_SECCOMP, ...)
  Cpus_allowed                mask of CPUs on which this process may run
  Cpus_allowed_list           Same as previous, but in "list format"

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 81818adb8e9ee3cc1adfbd5d0487d427f8c1f531..082676ab4878b177cc04b5ec60add2fa98519406 100644 (file)
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -342,10 +342,11 @@ static inline void task_cap(struct seq_file *m, struct task_struct *p)
 
 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
 {
+       seq_put_decimal_ull(m, "NoNewPrivs:\t", task_no_new_privs(p));
 #ifdef CONFIG_SECCOMP
-       seq_put_decimal_ull(m, "Seccomp:\t", p->seccomp.mode);
-       seq_putc(m, '\n');
+       seq_put_decimal_ull(m, "\nSeccomp:\t", p->seccomp.mode);
 #endif
+       seq_putc(m, '\n');
 }
 
 static inline void task_context_switch_counts(struct seq_file *m,