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 4a1745f1dadf..82a558b655da 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 d40e40a9446c..08562f419768 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: