improve sys_newuname() for compat architectures

[safe/jmp/linux-2.6] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index 20ccfb5..e483eb5 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -33,6 +33,7 @@
 #include <linux/task_io_accounting_ops.h>
 #include <linux/seccomp.h>
 #include <linux/cpu.h>
+#include <linux/personality.h>
 #include <linux/ptrace.h>
 #include <linux/fs_struct.h>
 
@@ -162,6 +163,7 @@ SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
        if (niceval > 19)
                niceval = 19;
 
+       rcu_read_lock();
        read_lock(&tasklist_lock);
        switch (which) {
                case PRIO_PROCESS:
@@ -199,6 +201,7 @@ SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
        }
 out_unlock:
        read_unlock(&tasklist_lock);
+       rcu_read_unlock();
 out:
        return error;
 }
@@ -220,6 +223,7 @@ SYSCALL_DEFINE2(getpriority, int, which, int, who)
        if (which > PRIO_USER || which < PRIO_PROCESS)
                return -EINVAL;
 
+       rcu_read_lock();
        read_lock(&tasklist_lock);
        switch (which) {
                case PRIO_PROCESS:
@@ -265,6 +269,7 @@ SYSCALL_DEFINE2(getpriority, int, which, int, who)
        }
 out_unlock:
        read_unlock(&tasklist_lock);
+       rcu_read_unlock();
 
        return retval;
 }
@@ -567,13 +572,7 @@ static int set_user(struct cred *new)
        if (!new_user)
                return -EAGAIN;
 
-       if (!task_can_switch_user(new_user, current)) {
-               free_uid(new_user);
-               return -EINVAL;
-       }
-
-       if (atomic_read(&new_user->processes) >=
-                               current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
+       if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
                        new_user != INIT_USER) {
                free_uid(new_user);
                return -EAGAIN;
@@ -1116,6 +1115,15 @@ out:
 
 DECLARE_RWSEM(uts_sem);
 
+#ifdef COMPAT_UTS_MACHINE
+#define override_architecture(name) \
+       (current->personality == PER_LINUX32 && \
+        copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
+                     sizeof(COMPAT_UTS_MACHINE)))
+#else
+#define override_architecture(name)    0
+#endif
+
 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
 {
        int errno = 0;
@@ -1124,6 +1132,9 @@ SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
        if (copy_to_user(name, utsname(), sizeof *name))
                errno = -EFAULT;
        up_read(&uts_sem);
+
+       if (!errno && override_architecture(name))
+               errno = -EFAULT;
        return errno;
 }