UBUNTU: SAUCE: Import aufs driver

[mirror_ubuntu-artful-kernel.git] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index 904199086490d5fdf05d0eda850d04a3ce572fa5..5c2c1ff3bd9a4811dac6d89da67fcf258e4ad57d 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -63,6 +63,8 @@
 #include <linux/compat.h>
 #include <linux/vmalloc.h>
 
+#include <trace/events/fs.h>
+
 #include <linux/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
@@ -109,6 +111,14 @@ bool path_noexec(const struct path *path)
        return (path->mnt->mnt_flags & MNT_NOEXEC) ||
               (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);
 }
+EXPORT_SYMBOL_GPL(path_noexec);
+
+bool path_nosuid(const struct path *path)
+{
+       return !mnt_may_suid(path->mnt) ||
+              (path->mnt->mnt_sb->s_iflags & SB_I_NOSUID);
+}
+EXPORT_SYMBOL(path_nosuid);
 
 #ifdef CONFIG_USELIB
 /*
@@ -220,8 +230,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 
        if (write) {
                unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
-               unsigned long ptr_size;
-               struct rlimit *rlim;
+               unsigned long ptr_size, limit;
 
                /*
                 * Since the stack will hold pointers to the strings, we
@@ -250,14 +259,16 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                        return page;
 
                /*
-                * Limit to 1/4-th the stack size for the argv+env strings.
+                * Limit to 1/4 of the max stack size or 3/4 of _STK_LIM
+                * (whichever is smaller) for the argv+env strings.
                 * This ensures that:
                 *  - the remaining binfmt code will not run out of stack space,
                 *  - the program will have a reasonable amount of stack left
                 *    to work from.
                 */
-               rlim = current->signal->rlim;
-               if (size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4)
+               limit = _STK_LIM / 4 * 3;
+               limit = min(limit, rlimit(RLIMIT_STACK) / 4);
+               if (size > limit)
                        goto fail;
        }
 
@@ -863,6 +874,8 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags)
        if (name->name[0] != '\0')
                fsnotify_open(file);
 
+       trace_open_exec(name->name);
+
 out:
        return file;
 
@@ -1451,6 +1464,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 {
        struct task_struct *p = current, *t;
        unsigned n_fs;
+       bool fs_recheck;
 
        if (p->ptrace)
                bprm->unsafe |= LSM_UNSAFE_PTRACE;
@@ -1462,6 +1476,8 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
        if (task_no_new_privs(current))
                bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
 
+recheck:
+       fs_recheck = false;
        t = p;
        n_fs = 1;
        spin_lock(&p->fs->lock);
@@ -1469,12 +1485,18 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
        while_each_thread(p, t) {
                if (t->fs == p->fs)
                        n_fs++;
+               if (t->flags & (PF_EXITING | PF_FORKNOEXEC))
+                       fs_recheck  = true;
        }
        rcu_read_unlock();
 
-       if (p->fs->users > n_fs)
+       if (p->fs->users > n_fs) {
+               if (fs_recheck) {
+                       spin_unlock(&p->fs->lock);
+                       goto recheck;
+               }
                bprm->unsafe |= LSM_UNSAFE_SHARE;
-       else
+       } else
                p->fs->in_exec = 1;
        spin_unlock(&p->fs->lock);
 }
@@ -1495,7 +1517,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm)
        bprm->cred->euid = current_euid();
        bprm->cred->egid = current_egid();
 
-       if (!mnt_may_suid(bprm->file->f_path.mnt))
+       if (path_nosuid(&bprm->file->f_path))
                return;
 
        if (task_no_new_privs(current))