move seccomp from /proc to a prctl

This reduces the memory footprint and it enforces that only the current
task can enable seccomp on itself (this is a requirement for a
strightforward [modulo preempt ;) ] TIF_NOTSC implementation).

Signed-off-by: Andrea Arcangeli <andrea@cpushare.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 72 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index d0921944e68c..ae3627337a92 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -67,7 +67,6 @@
 #include <linux/mount.h>
 #include <linux/security.h>
 #include <linux/ptrace.h>
-#include <linux/seccomp.h>
 #include <linux/cpuset.h>
 #include <linux/audit.h>
 #include <linux/poll.h>
@@ -817,71 +816,6 @@ static const struct file_operations proc_loginuid_operations = {
 };
 #endif
 
-#ifdef CONFIG_SECCOMP
-static ssize_t seccomp_read(struct file *file, char __user *buf,
-                            size_t count, loff_t *ppos)
-{
-        struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
-        char __buf[20];
-        size_t len;
-
-        if (!tsk)
-                return -ESRCH;
-        /* no need to print the trailing zero, so use only len */
-        len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
-        put_task_struct(tsk);
-
-        return simple_read_from_buffer(buf, count, ppos, __buf, len);
-}
-
-static ssize_t seccomp_write(struct file *file, const char __user *buf,
-                             size_t count, loff_t *ppos)
-{
-        struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
-        char __buf[20], *end;
-        unsigned int seccomp_mode;
-        ssize_t result;
-
-        result = -ESRCH;
-        if (!tsk)
-                goto out_no_task;
-
-        /* can set it only once to be even more secure */
-        result = -EPERM;
-        if (unlikely(tsk->seccomp.mode))
-                goto out;
-
-        result = -EFAULT;
-        memset(__buf, 0, sizeof(__buf));
-        count = min(count, sizeof(__buf) - 1);
-        if (copy_from_user(__buf, buf, count))
-                goto out;
-
-        seccomp_mode = simple_strtoul(__buf, &end, 0);
-        if (*end == '\n')
-                end++;
-        result = -EINVAL;
-        if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
-                tsk->seccomp.mode = seccomp_mode;
-                set_tsk_thread_flag(tsk, TIF_SECCOMP);
-        } else
-                goto out;
-        result = -EIO;
-        if (unlikely(!(end - __buf)))
-                goto out;
-        result = end - __buf;
-out:
-        put_task_struct(tsk);
-out_no_task:
-        return result;
-}
-
-static const struct file_operations proc_seccomp_operations = {
-        .read           = seccomp_read,
-        .write          = seccomp_write,
-};
-#endif /* CONFIG_SECCOMP */
-
 #ifdef CONFIG_FAULT_INJECTION
 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
                                       size_t count, loff_t *ppos)
@@ -2042,9 +1976,6 @@ static const struct pid_entry tgid_base_stuff[] = {
         REG("numa_maps",  S_IRUGO, numa_maps),
 #endif
         REG("mem",        S_IRUSR|S_IWUSR, mem),
-#ifdef CONFIG_SECCOMP
-        REG("seccomp",    S_IRUSR|S_IWUSR, seccomp),
-#endif
         LNK("cwd",        cwd),
         LNK("root",       root),
         LNK("exe",        exe),
@@ -2329,9 +2260,6 @@ static const struct pid_entry tid_base_stuff[] = {
         REG("numa_maps", S_IRUGO, numa_maps),
 #endif
         REG("mem",       S_IRUSR|S_IWUSR, mem),
-#ifdef CONFIG_SECCOMP
-        REG("seccomp",   S_IRUSR|S_IWUSR, seccomp),
-#endif
         LNK("cwd",       cwd),
         LNK("root",      root),
         LNK("exe",       exe),