1 files changed, 101 insertions, 56 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 606cf96828d5..029308754eea 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -46,7 +46,6 @@
 #include <linux/proc_fs.h>
 #include <linux/mount.h>
 #include <linux/security.h>
-#include <linux/ima.h>
 #include <linux/syscalls.h>
 #include <linux/tsacct_kern.h>
 #include <linux/cn_proc.h>
@@ -198,7 +197,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                  *    to work from.
                  */
                 rlim = current->signal->rlim;
-                if (size > rlim[RLIMIT_STACK].rlim_cur / 4) {
+                if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) {
                         put_page(page);
                         return NULL;
                 }
@@ -249,6 +248,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
         vma->vm_start = vma->vm_end - PAGE_SIZE;
         vma->vm_flags = VM_STACK_FLAGS;
         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+        INIT_LIST_HEAD(&vma->anon_vma_chain);
         err = insert_vm_struct(mm, vma);
         if (err)
                 goto err;
@@ -519,7 +519,8 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
         /*
          * cover the whole range: [new_start, old_end)
          */
-        vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
+        if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL))
+                return -ENOMEM;
 
         /*
          * move the page tables downwards, on failure we rely on
@@ -550,15 +551,13 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
         tlb_finish_mmu(tlb, new_end, old_end);
 
         /*
-         * shrink the vma to just the new range.
+         * Shrink the vma to just the new range.  Always succeeds.
          */
         vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
 
         return 0;
 }
 
-#define EXTRA_STACK_VM_PAGES    20      /* random */
-
 /*
  * Finalizes the stack vm_area_struct. The flags and permissions are updated,
  * the stack is optionally relocated, and some extra space is added.
@@ -574,10 +573,13 @@ int setup_arg_pages(struct linux_binprm *bprm,
         struct vm_area_struct *prev = NULL;
         unsigned long vm_flags;
         unsigned long stack_base;
+        unsigned long stack_size;
+        unsigned long stack_expand;
+        unsigned long rlim_stack;
 
 #ifdef CONFIG_STACK_GROWSUP
         /* Limit stack size to 1GB */
-        stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
+        stack_base = rlimit_max(RLIMIT_STACK);
         if (stack_base > (1 << 30))
                 stack_base = 1 << 30;
 
@@ -630,10 +632,23 @@ int setup_arg_pages(struct linux_binprm *bprm,
                         goto out_unlock;
         }
 
+        stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
+        stack_size = vma->vm_end - vma->vm_start;
+        /*
+         * Align this down to a page boundary as expand_stack
+         * will align it up.
+         */
+        rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK;
 #ifdef CONFIG_STACK_GROWSUP
-        stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+        if (stack_size + stack_expand > rlim_stack)
+                stack_base = vma->vm_start + rlim_stack;
+        else
+                stack_base = vma->vm_end + stack_expand;
 #else
-        stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+        if (stack_size + stack_expand > rlim_stack)
+                stack_base = vma->vm_end - rlim_stack;
+        else
+                stack_base = vma->vm_start - stack_expand;
 #endif
         ret = expand_stack(vma, stack_base);
         if (ret)
@@ -705,6 +720,7 @@ static int exec_mmap(struct mm_struct *mm)
         /* Notify parent that we're no longer interested in the old VM */
         tsk = current;
         old_mm = current->mm;
+        sync_mm_rss(tsk, old_mm);
         mm_release(tsk, old_mm);
 
         if (old_mm) {
@@ -829,7 +845,9 @@ static int de_thread(struct task_struct *tsk)
                 attach_pid(tsk, PIDTYPE_PID,  task_pid(leader));
                 transfer_pid(leader, tsk, PIDTYPE_PGID);
                 transfer_pid(leader, tsk, PIDTYPE_SID);
+
                 list_replace_rcu(&leader->tasks, &tsk->tasks);
+                list_replace_init(&leader->sibling, &tsk->sibling);
 
                 tsk->group_leader = tsk;
                 leader->group_leader = tsk;
@@ -926,6 +944,15 @@ char *get_task_comm(char *buf, struct task_struct *tsk)
 void set_task_comm(struct task_struct *tsk, char *buf)
 {
         task_lock(tsk);
+
+        /*
+         * Threads may access current->comm without holding
+         * the task lock, so write the string carefully.
+         * Readers without a lock may see incomplete new
+         * names but are safe from non-terminating string reads.
+         */
+        memset(tsk->comm, 0, TASK_COMM_LEN);
+        wmb();
         strlcpy(tsk->comm, buf, sizeof(tsk->comm));
         task_unlock(tsk);
         perf_event_comm(tsk);
@@ -933,9 +960,7 @@ void set_task_comm(struct task_struct *tsk, char *buf)
 
 int flush_old_exec(struct linux_binprm * bprm)
 {
-        char * name;
-        int i, ch, retval;
-        char tcomm[sizeof(current->comm)];
+        int retval;
 
         /*
          * Make sure we have a private signal table and that
@@ -956,6 +981,25 @@ int flush_old_exec(struct linux_binprm * bprm)
 
         bprm->mm = NULL;                /* We're using it now */
 
+        current->flags &= ~PF_RANDOMIZE;
+        flush_thread();
+        current->personality &= ~bprm->per_clear;
+
+        return 0;
+
+out:
+        return retval;
+}
+EXPORT_SYMBOL(flush_old_exec);
+
+void setup_new_exec(struct linux_binprm * bprm)
+{
+        int i, ch;
+        char * name;
+        char tcomm[sizeof(current->comm)];
+
+        arch_pick_mmap_layout(current->mm);
+
         /* This is the point of no return */
         current->sas_ss_sp = current->sas_ss_size = 0;
 
@@ -977,9 +1021,6 @@ int flush_old_exec(struct linux_binprm * bprm)
         tcomm[i] = '\0';
         set_task_comm(current, tcomm);
 
-        current->flags &= ~PF_RANDOMIZE;
-        flush_thread();
-
         /* Set the new mm task size. We have to do that late because it may
          * depend on TIF_32BIT which is only updated in flush_thread() on
          * some architectures like powerpc
@@ -995,8 +1036,6 @@ int flush_old_exec(struct linux_binprm * bprm)
                 set_dumpable(current->mm, suid_dumpable);
         }
 
-        current->personality &= ~bprm->per_clear;
-
         /*
          * Flush performance counters when crossing a
          * security domain:
@@ -1011,14 +1050,8 @@ int flush_old_exec(struct linux_binprm * bprm)
 
         flush_signal_handlers(current, 0);
         flush_old_files(current->files);
-
-        return 0;
-
-out:
-        return retval;
 }
-
-EXPORT_SYMBOL(flush_old_exec);
+EXPORT_SYMBOL(setup_new_exec);
 
 /*
  * Prepare credentials and lock ->cred_guard_mutex.
@@ -1211,9 +1244,6 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
         retval = security_bprm_check(bprm);
         if (retval)
                 return retval;
-        retval = ima_bprm_check(bprm);
-        if (retval)
-                return retval;
 
         /* kernel module loader fixup */
         /* so we don't try to load run modprobe in kernel space. */
@@ -1360,8 +1390,6 @@ int do_execve(char * filename,
         if (retval < 0)
                 goto out;
 
-        current->stack_start = current->mm->start_stack;
-
         /* execve succeeded */
         current->fs->in_exec = 0;
         current->in_execve = 0;
@@ -1506,7 +1534,7 @@ static int format_corename(char *corename, long signr)
                         /* core limit size */
                         case 'c':
                                 rc = snprintf(out_ptr, out_end - out_ptr,
-                                              "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
+                                              "%lu", rlimit(RLIMIT_CORE));
                                 if (rc > out_end - out_ptr)
                                         goto out;
                                 out_ptr += rc;
@@ -1534,12 +1562,13 @@ out:
         return ispipe;
 }
 
-static int zap_process(struct task_struct *start)
+static int zap_process(struct task_struct *start, int exit_code)
 {
         struct task_struct *t;
         int nr = 0;
 
         start->signal->flags = SIGNAL_GROUP_EXIT;
+        start->signal->group_exit_code = exit_code;
         start->signal->group_stop_count = 0;
 
         t = start;
@@ -1564,8 +1593,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
         spin_lock_irq(&tsk->sighand->siglock);
         if (!signal_group_exit(tsk->signal)) {
                 mm->core_state = core_state;
-                tsk->signal->group_exit_code = exit_code;
-                nr = zap_process(tsk);
+                nr = zap_process(tsk, exit_code);
         }
         spin_unlock_irq(&tsk->sighand->siglock);
         if (unlikely(nr < 0))
@@ -1614,7 +1642,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
                         if (p->mm) {
                                 if (unlikely(p->mm == mm)) {
                                         lock_task_sighand(p, &flags);
-                                        nr += zap_process(p);
+                                        nr += zap_process(p, exit_code);
                                         unlock_task_sighand(p, &flags);
                                 }
                                 break;
@@ -1721,14 +1749,19 @@ void set_dumpable(struct mm_struct *mm, int value)
         }
 }
 
-int get_dumpable(struct mm_struct *mm)
+static int __get_dumpable(unsigned long mm_flags)
 {
         int ret;
 
-        ret = mm->flags & 0x3;
+        ret = mm_flags & MMF_DUMPABLE_MASK;
         return (ret >= 2) ? 2 : ret;
 }
 
+int get_dumpable(struct mm_struct *mm)
+{
+        return __get_dumpable(mm->flags);
+}
+
 static void wait_for_dump_helpers(struct file *file)
 {
         struct pipe_inode_info *pipe;
@@ -1759,17 +1792,26 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
         struct mm_struct *mm = current->mm;
         struct linux_binfmt * binfmt;
         struct inode * inode;
-        struct file * file;
         const struct cred *old_cred;
         struct cred *cred;
         int retval = 0;
         int flag = 0;
         int ispipe = 0;
-        unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
         char **helper_argv = NULL;
         int helper_argc = 0;
         int dump_count = 0;
         static atomic_t core_dump_count = ATOMIC_INIT(0);
+        struct coredump_params cprm = {
+                .signr = signr,
+                .regs = regs,
+                .limit = rlimit(RLIMIT_CORE),
+                /*
+                 * We must use the same mm->flags while dumping core to avoid
+                 * inconsistency of bit flags, since this flag is not protected
+                 * by any locks.
+                 */
+                .mm_flags = mm->flags,
+        };
 
         audit_core_dumps(signr);
 
@@ -1787,7 +1829,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
         /*
          * If another thread got here first, or we are not dumpable, bail out.
          */
-        if (mm->core_state || !get_dumpable(mm)) {
+        if (mm->core_state || !__get_dumpable(cprm.mm_flags)) {
                 up_write(&mm->mmap_sem);
                 put_cred(cred);
                 goto fail;
@@ -1798,7 +1840,8 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
          *      process nor do we know its entire history. We only know it
          *      was tainted so we dump it as root in mode 2.
          */
-        if (get_dumpable(mm) == 2) {    /* Setuid core dump mode */
+        if (__get_dumpable(cprm.mm_flags) == 2) {
+                /* Setuid core dump mode */
                 flag = O_EXCL;          /* Stop rewrite attacks */
                 cred->fsuid = 0;        /* Dump root private */
         }
@@ -1825,15 +1868,15 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
         ispipe = format_corename(corename, signr);
         unlock_kernel();
 
-        if ((!ispipe) && (core_limit < binfmt->min_coredump))
+        if ((!ispipe) && (cprm.limit < binfmt->min_coredump))
                 goto fail_unlock;
 
         if (ispipe) {
-                if (core_limit == 0) {
+                if (cprm.limit == 0) {
                         /*
                          * Normally core limits are irrelevant to pipes, since
                          * we're not writing to the file system, but we use
-                         * core_limit of 0 here as a speacial value. Any
+                         * cprm.limit of 0 here as a speacial value. Any
                          * non-zero limit gets set to RLIM_INFINITY below, but
                          * a limit of 0 skips the dump.  This is a consistent
                          * way to catch recursive crashes.  We can still crash
@@ -1866,25 +1909,25 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
                         goto fail_dropcount;
                 }
 
-                core_limit = RLIM_INFINITY;
+                cprm.limit = RLIM_INFINITY;
 
                 /* SIGPIPE can happen, but it's just never processed */
                 if (call_usermodehelper_pipe(helper_argv[0], helper_argv, NULL,
-                                &file)) {
+                                &cprm.file)) {
                         printk(KERN_INFO "Core dump to %s pipe failed\n",
                                corename);
                         goto fail_dropcount;
                 }
         } else
-                file = filp_open(corename,
+                cprm.file = filp_open(corename,
                                  O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
                                  0600);
-        if (IS_ERR(file))
+        if (IS_ERR(cprm.file))
                 goto fail_dropcount;
-        inode = file->f_path.dentry->d_inode;
+        inode = cprm.file->f_path.dentry->d_inode;
         if (inode->i_nlink > 1)
                 goto close_fail;        /* multiple links - don't dump */
-        if (!ispipe && d_unhashed(file->f_path.dentry))
+        if (!ispipe && d_unhashed(cprm.file->f_path.dentry))
                 goto close_fail;
 
         /* AK: actually i see no reason to not allow this for named pipes etc.,
@@ -1894,24 +1937,26 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
         /*
          * Dont allow local users get cute and trick others to coredump
          * into their pre-created files:
+         * Note, this is not relevant for pipes
          */
-        if (inode->i_uid != current_fsuid())
+        if (!ispipe && (inode->i_uid != current_fsuid()))
                 goto close_fail;
-        if (!file->f_op)
+        if (!cprm.file->f_op)
                 goto close_fail;
-        if (!file->f_op->write)
+        if (!cprm.file->f_op->write)
                 goto close_fail;
-        if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
+        if (!ispipe &&
+            do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file) != 0)
                 goto close_fail;
 
-        retval = binfmt->core_dump(signr, regs, file, core_limit);
+        retval = binfmt->core_dump(&cprm);
 
         if (retval)
                 current->signal->group_exit_code |= 0x80;
 close_fail:
         if (ispipe && core_pipe_limit)
-                wait_for_dump_helpers(file);
-        filp_close(file, NULL);
+                wait_for_dump_helpers(cprm.file);
+        filp_close(cprm.file, NULL);
 fail_dropcount:
         if (dump_count)
                 atomic_dec(&core_dump_count);