coredump masking: reimplementation of dumpable using two flags

This patch changes mm_struct.dumpable to a pair of bit flags.

set_dumpable() converts three-value dumpable to two flags and stores it into
lower two bits of mm_struct.flags instead of mm_struct.dumpable.
get_dumpable() behaves in the opposite way.

[akpm@linux-foundation.org: export set_dumpable]
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 13 insertions, 13 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 4a1745f1dad..82a558b655d 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -142,7 +142,7 @@ static int may_attach(struct task_struct *task)
                 return -EPERM;
         smp_rmb();
         if (task->mm)
-                dumpable = task->mm->dumpable;
+                dumpable = get_dumpable(task->mm);
         if (!dumpable && !capable(CAP_SYS_PTRACE))
                 return -EPERM;
 
diff --git a/kernel/sys.c b/kernel/sys.c
index d40e40a9446..08562f41976 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1036,7 +1036,7 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
                         return -EPERM;
         }
         if (new_egid != old_egid) {
-                current->mm->dumpable = suid_dumpable;
+                set_dumpable(current->mm, suid_dumpable);
                 smp_wmb();
         }
         if (rgid != (gid_t) -1 ||
@@ -1066,13 +1066,13 @@ asmlinkage long sys_setgid(gid_t gid)
 
         if (capable(CAP_SETGID)) {
                 if (old_egid != gid) {
-                        current->mm->dumpable = suid_dumpable;
+                        set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
                 current->gid = current->egid = current->sgid = current->fsgid = gid;
         } else if ((gid == current->gid) || (gid == current->sgid)) {
                 if (old_egid != gid) {
-                        current->mm->dumpable = suid_dumpable;
+                        set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
                 current->egid = current->fsgid = gid;
@@ -1103,7 +1103,7 @@ static int set_user(uid_t new_ruid, int dumpclear)
         switch_uid(new_user);
 
         if (dumpclear) {
-                current->mm->dumpable = suid_dumpable;
+                set_dumpable(current->mm, suid_dumpable);
                 smp_wmb();
         }
         current->uid = new_ruid;
@@ -1159,7 +1159,7 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
                 return -EAGAIN;
 
         if (new_euid != old_euid) {
-                current->mm->dumpable = suid_dumpable;
+                set_dumpable(current->mm, suid_dumpable);
                 smp_wmb();
         }
         current->fsuid = current->euid = new_euid;
@@ -1209,7 +1209,7 @@ asmlinkage long sys_setuid(uid_t uid)
                 return -EPERM;
 
         if (old_euid != uid) {
-                current->mm->dumpable = suid_dumpable;
+                set_dumpable(current->mm, suid_dumpable);
                 smp_wmb();
         }
         current->fsuid = current->euid = uid;
@@ -1254,7 +1254,7 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
         }
         if (euid != (uid_t) -1) {
                 if (euid != current->euid) {
-                        current->mm->dumpable = suid_dumpable;
+                        set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
                 current->euid = euid;
@@ -1304,7 +1304,7 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
         }
         if (egid != (gid_t) -1) {
                 if (egid != current->egid) {
-                        current->mm->dumpable = suid_dumpable;
+                        set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
                 current->egid = egid;
@@ -1350,7 +1350,7 @@ asmlinkage long sys_setfsuid(uid_t uid)
             uid == current->suid || uid == current->fsuid || 
             capable(CAP_SETUID)) {
                 if (uid != old_fsuid) {
-                        current->mm->dumpable = suid_dumpable;
+                        set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
                 current->fsuid = uid;
@@ -1379,7 +1379,7 @@ asmlinkage long sys_setfsgid(gid_t gid)
             gid == current->sgid || gid == current->fsgid || 
             capable(CAP_SETGID)) {
                 if (gid != old_fsgid) {
-                        current->mm->dumpable = suid_dumpable;
+                        set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
                 current->fsgid = gid;
@@ -2176,14 +2176,14 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                         error = put_user(current->pdeath_signal, (int __user *)arg2);
                         break;
                 case PR_GET_DUMPABLE:
-                        error = current->mm->dumpable;
+                        error = get_dumpable(current->mm);
                         break;
                 case PR_SET_DUMPABLE:
                         if (arg2 < 0 || arg2 > 1) {
                                 error = -EINVAL;
                                 break;
                         }
-                        current->mm->dumpable = arg2;
+                        set_dumpable(current->mm, arg2);
                         break;
 
                 case PR_SET_UNALIGN: