SUNRPC: Add generic helpers for xdr_stream encode/decode

[karo-tx-linux.git] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index 923c57d96899f821f65a68359e8657c576691fdf..e579466107335bf4b704863469a4162c8c335adb 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -19,7 +19,7 @@
  * current->executable is only used by the procfs.  This allows a dispatch
  * table to check for several different types  of binary formats.  We keep
  * trying until we recognize the file or we run out of supported binary
- * formats. 
+ * formats.
  */
 
 #include <linux/slab.h>
@@ -58,7 +58,7 @@
 #include <linux/compat.h>
 #include <linux/vmalloc.h>
 
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
 
@@ -209,7 +209,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
         * doing the exec and bprm->mm is the new process's mm.
         */
        ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags,
-                       &page, NULL);
+                       &page, NULL, NULL);
        if (ret <= 0)
                return NULL;
 
@@ -1268,6 +1268,13 @@ int flush_old_exec(struct linux_binprm * bprm)
        flush_thread();
        current->personality &= ~bprm->per_clear;
 
+       /*
+        * We have to apply CLOEXEC before we change whether the process is
+        * dumpable (in setup_new_exec) to avoid a race with a process in userspace
+        * trying to access the should-be-closed file descriptors of a process
+        * undergoing exec(2).
+        */
+       do_close_on_exec(current->files);
        return 0;
 
 out:
@@ -1277,8 +1284,22 @@ EXPORT_SYMBOL(flush_old_exec);
 
 void would_dump(struct linux_binprm *bprm, struct file *file)
 {
-       if (inode_permission(file_inode(file), MAY_READ) < 0)
+       struct inode *inode = file_inode(file);
+       if (inode_permission(inode, MAY_READ) < 0) {
+               struct user_namespace *old, *user_ns;
                bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
+
+               /* Ensure mm->user_ns contains the executable */
+               user_ns = old = bprm->mm->user_ns;
+               while ((user_ns != &init_user_ns) &&
+                      !privileged_wrt_inode_uidgid(user_ns, inode))
+                       user_ns = user_ns->parent;
+
+               if (old != user_ns) {
+                       bprm->mm->user_ns = get_user_ns(user_ns);
+                       put_user_ns(old);
+               }
+       }
 }
 EXPORT_SYMBOL(would_dump);
 
@@ -1308,7 +1329,6 @@ void setup_new_exec(struct linux_binprm * bprm)
            !gid_eq(bprm->cred->gid, current_egid())) {
                current->pdeath_signal = 0;
        } else {
-               would_dump(bprm, bprm->file);
                if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)
                        set_dumpable(current->mm, suid_dumpable);
        }
@@ -1317,7 +1337,6 @@ void setup_new_exec(struct linux_binprm * bprm)
           group */
        current->self_exec_id++;
        flush_signal_handlers(current, 0);
-       do_close_on_exec(current->files);
 }
 EXPORT_SYMBOL(setup_new_exec);
 
@@ -1408,7 +1427,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
        unsigned n_fs;
 
        if (p->ptrace) {
-               if (p->ptrace & PT_PTRACE_CAP)
+               if (ptracer_capable(p, current_user_ns()))
                        bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP;
                else
                        bprm->unsafe |= LSM_UNSAFE_PTRACE;
@@ -1743,6 +1762,8 @@ static int do_execveat_common(int fd, struct filename *filename,
        if (retval < 0)
                goto out;
 
+       would_dump(bprm, bprm->file);
+
        retval = exec_binprm(bprm);
        if (retval < 0)
                goto out;