2.6.25-rc7

 kernel

diff --git a/kernel/capability.c b/kernel/capability.c
index efbd9cd..39e8193 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -22,6 +22,37 @@
 static DEFINE_SPINLOCK(task_capability_lock);
 
 /*
+ * Leveraged for setting/resetting capabilities
+ */
+
+const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
+const kernel_cap_t __cap_full_set = CAP_FULL_SET;
+const kernel_cap_t __cap_init_eff_set = CAP_INIT_EFF_SET;
+
+EXPORT_SYMBOL(__cap_empty_set);
+EXPORT_SYMBOL(__cap_full_set);
+EXPORT_SYMBOL(__cap_init_eff_set);
+
+/*
+ * More recent versions of libcap are available from:
+ *
+ *   http://www.kernel.org/pub/linux/libs/security/linux-privs/
+ */
+
+static void warn_legacy_capability_use(void)
+{
+   static int warned;
+   if (!warned) {
+      char name[sizeof(current->comm)];
+
+      printk(KERN_INFO "warning: `%s' uses 32-bit capabilities"
+             " (legacy support in use)\n",
+             get_task_comm(name, current));
+      warned = 1;
+   }
+}
+
+/*
  * For sys_getproccap() and sys_setproccap(), any of the three
  * capability set pointers may be NULL -- indicating that that set is
  * uninteresting and/or not to be changed.
@@ -42,12 +73,21 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
    pid_t pid;
    __u32 version;
    struct task_struct *target;
-   struct __user_cap_data_struct data;
+   unsigned tocopy;
+   kernel_cap_t pE, pI, pP;
 
    if (get_user(version, &header->version))
       return -EFAULT;
 
-   if (version != _LINUX_CAPABILITY_VERSION) {
+   switch (version) {
+   case _LINUX_CAPABILITY_VERSION_1:
+      warn_legacy_capability_use();
+      tocopy = _LINUX_CAPABILITY_U32S_1;
+      break;
+   case _LINUX_CAPABILITY_VERSION_2:
+      tocopy = _LINUX_CAPABILITY_U32S_2;
+      break;
+   default:
       if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
          return -EFAULT;
       return -EINVAL;
@@ -71,14 +111,47 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
    } else
       target = current;
 
-   ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
+   ret = security_capget(target, &pE, &pI, &pP);
 
 out:
    read_unlock(&tasklist_lock);
    spin_unlock(&task_capability_lock);
 
-   if (!ret && copy_to_user(dataptr, &data, sizeof data))
-      return -EFAULT;
+   if (!ret) {
+      struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
+      unsigned i;
+
+      for (i = 0; i < tocopy; i++) {
+         kdata[i].effective = pE.cap[i];
+         kdata[i].permitted = pP.cap[i];
+         kdata[i].inheritable = pI.cap[i];
+      }
+
+      /*
+       * Note, in the case, tocopy < _LINUX_CAPABILITY_U32S,
+       * we silently drop the upper capabilities here. This
+       * has the effect of making older libcap
+       * implementations implicitly drop upper capability
+       * bits when they perform a: capget/modify/capset
+       * sequence.
+       *
+       * This behavior is considered fail-safe
+       * behavior. Upgrading the application to a newer
+       * version of libcap will enable access to the newer
+       * capabilities.
+       *
+       * An alternative would be to return an error here
+       * (-ERANGE), but that causes legacy applications to
+       * unexpectidly fail; the capget/modify/capset aborts
+       * before modification is attempted and the application
+       * fails.
+       */
+
+      if (copy_to_user(dataptr, kdata, tocopy
+             * sizeof(struct __user_cap_data_struct))) {
+         return -EFAULT;
+      }
+   }
 
    return ret;
 }
@@ -167,6 +240,8 @@ static inline int cap_set_all(kernel_cap_t *effective,
  */
 asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
 {
+   struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
+   unsigned i, tocopy;
    kernel_cap_t inheritable, permitted, effective;
    __u32 version;
    struct task_struct *target;
@@ -176,7 +251,15 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
    if (get_user(version, &header->version))
       return -EFAULT;
 
-   if (version != _LINUX_CAPABILITY_VERSION) {
+   switch (version) {
+   case _LINUX_CAPABILITY_VERSION_1:
+      warn_legacy_capability_use();
+      tocopy = _LINUX_CAPABILITY_U32S_1;
+      break;
+   case _LINUX_CAPABILITY_VERSION_2:
+      tocopy = _LINUX_CAPABILITY_U32S_2;
+      break;
+   default:
       if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
          return -EFAULT;
       return -EINVAL;
@@ -188,10 +271,22 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
    if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
       return -EPERM;
 
-   if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
-       copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
-       copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
+   if (copy_from_user(&kdata, data, tocopy
+            * sizeof(struct __user_cap_data_struct))) {
       return -EFAULT;
+   }
+
+   for (i = 0; i < tocopy; i++) {
+      effective.cap[i] = kdata[i].effective;
+      permitted.cap[i] = kdata[i].permitted;
+      inheritable.cap[i] = kdata[i].inheritable;
+   }
+   while (i < _LINUX_CAPABILITY_U32S) {
+      effective.cap[i] = 0;
+      permitted.cap[i] = 0;
+      inheritable.cap[i] = 0;
+      i++;
+   }
 
    spin_lock(&task_capability_lock);
    read_lock(&tasklist_lock);