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Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c83
1 files changed, 51 insertions, 32 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 60c0b4868fd4..1450b461d196 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -16,7 +16,6 @@
#include <linux/slab.h>
#include <linux/sched/autogroup.h>
#include <linux/sched/mm.h>
-#include <linux/sched/coredump.h>
#include <linux/sched/user.h>
#include <linux/sched/numa_balancing.h>
#include <linux/sched/stat.h>
@@ -105,6 +104,7 @@
#include <linux/rseq.h>
#include <uapi/linux/pidfd.h>
#include <linux/pidfs.h>
+#include <linux/tick.h>
#include <asm/pgalloc.h>
#include <linux/uaccess.h>
@@ -621,6 +621,12 @@ static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm)
exe_file = get_mm_exe_file(oldmm);
RCU_INIT_POINTER(mm->exe_file, exe_file);
+ /*
+ * We depend on the oldmm having properly denied write access to the
+ * exe_file already.
+ */
+ if (exe_file && deny_write_access(exe_file))
+ pr_warn_once("deny_write_access() failed in %s\n", __func__);
}
#ifdef CONFIG_MMU
@@ -653,11 +659,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
mm->exec_vm = oldmm->exec_vm;
mm->stack_vm = oldmm->stack_vm;
- retval = ksm_fork(mm, oldmm);
- if (retval)
- goto out;
- khugepaged_fork(mm, oldmm);
-
/* Use __mt_dup() to efficiently build an identical maple tree. */
retval = __mt_dup(&oldmm->mm_mt, &mm->mm_mt, GFP_KERNEL);
if (unlikely(retval))
@@ -760,6 +761,8 @@ loop_out:
vma_iter_free(&vmi);
if (!retval) {
mt_set_in_rcu(vmi.mas.tree);
+ ksm_fork(mm, oldmm);
+ khugepaged_fork(mm, oldmm);
} else if (mpnt) {
/*
* The entire maple tree has already been duplicated. If the
@@ -775,7 +778,10 @@ out:
mmap_write_unlock(mm);
flush_tlb_mm(oldmm);
mmap_write_unlock(oldmm);
- dup_userfaultfd_complete(&uf);
+ if (!retval)
+ dup_userfaultfd_complete(&uf);
+ else
+ dup_userfaultfd_fail(&uf);
fail_uprobe_end:
uprobe_end_dup_mmap();
return retval;
@@ -1184,7 +1190,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->active_memcg = NULL;
#endif
-#ifdef CONFIG_CPU_SUP_INTEL
+#ifdef CONFIG_X86_BUS_LOCK_DETECT
tsk->reported_split_lock = 0;
#endif
@@ -1298,7 +1304,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
if (init_new_context(p, mm))
goto fail_nocontext;
- if (mm_alloc_cid(mm))
+ if (mm_alloc_cid(mm, p))
goto fail_cid;
if (percpu_counter_init_many(mm->rss_stat, 0, GFP_KERNEL_ACCOUNT,
@@ -1413,11 +1419,20 @@ int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
*/
old_exe_file = rcu_dereference_raw(mm->exe_file);
- if (new_exe_file)
+ if (new_exe_file) {
+ /*
+ * We expect the caller (i.e., sys_execve) to already denied
+ * write access, so this is unlikely to fail.
+ */
+ if (unlikely(deny_write_access(new_exe_file)))
+ return -EACCES;
get_file(new_exe_file);
+ }
rcu_assign_pointer(mm->exe_file, new_exe_file);
- if (old_exe_file)
+ if (old_exe_file) {
+ allow_write_access(old_exe_file);
fput(old_exe_file);
+ }
return 0;
}
@@ -1456,6 +1471,9 @@ int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
return ret;
}
+ ret = deny_write_access(new_exe_file);
+ if (ret)
+ return -EACCES;
get_file(new_exe_file);
/* set the new file */
@@ -1464,8 +1482,10 @@ int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
rcu_assign_pointer(mm->exe_file, new_exe_file);
mmap_write_unlock(mm);
- if (old_exe_file)
+ if (old_exe_file) {
+ allow_write_access(old_exe_file);
fput(old_exe_file);
+ }
return 0;
}
@@ -1545,8 +1565,9 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
return ERR_PTR(err);
mm = get_task_mm(task);
- if (mm && mm != current->mm &&
- !ptrace_may_access(task, mode)) {
+ if (!mm) {
+ mm = ERR_PTR(-ESRCH);
+ } else if (mm != current->mm && !ptrace_may_access(task, mode)) {
mmput(mm);
mm = ERR_PTR(-EACCES);
}
@@ -1756,33 +1777,30 @@ static int copy_files(unsigned long clone_flags, struct task_struct *tsk,
int no_files)
{
struct files_struct *oldf, *newf;
- int error = 0;
/*
* A background process may not have any files ...
*/
oldf = current->files;
if (!oldf)
- goto out;
+ return 0;
if (no_files) {
tsk->files = NULL;
- goto out;
+ return 0;
}
if (clone_flags & CLONE_FILES) {
atomic_inc(&oldf->count);
- goto out;
+ return 0;
}
- newf = dup_fd(oldf, NR_OPEN_MAX, &error);
- if (!newf)
- goto out;
+ newf = dup_fd(oldf, NULL);
+ if (IS_ERR(newf))
+ return PTR_ERR(newf);
tsk->files = newf;
- error = 0;
-out:
- return error;
+ return 0;
}
static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
@@ -1864,6 +1882,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
#ifdef CONFIG_POSIX_TIMERS
INIT_HLIST_HEAD(&sig->posix_timers);
+ INIT_HLIST_HEAD(&sig->ignored_posix_timers);
hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
sig->real_timer.function = it_real_fn;
#endif
@@ -2295,6 +2314,7 @@ __latent_entropy struct task_struct *copy_process(
acct_clear_integrals(p);
posix_cputimers_init(&p->posix_cputimers);
+ tick_dep_init_task(p);
p->io_context = NULL;
audit_set_context(p, NULL);
@@ -3238,17 +3258,16 @@ static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
/*
* Unshare file descriptor table if it is being shared
*/
-int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
- struct files_struct **new_fdp)
+static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
{
struct files_struct *fd = current->files;
- int error = 0;
if ((unshare_flags & CLONE_FILES) &&
(fd && atomic_read(&fd->count) > 1)) {
- *new_fdp = dup_fd(fd, max_fds, &error);
- if (!*new_fdp)
- return error;
+ fd = dup_fd(fd, NULL);
+ if (IS_ERR(fd))
+ return PTR_ERR(fd);
+ *new_fdp = fd;
}
return 0;
@@ -3306,7 +3325,7 @@ int ksys_unshare(unsigned long unshare_flags)
err = unshare_fs(unshare_flags, &new_fs);
if (err)
goto bad_unshare_out;
- err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd);
+ err = unshare_fd(unshare_flags, &new_fd);
if (err)
goto bad_unshare_cleanup_fs;
err = unshare_userns(unshare_flags, &new_cred);
@@ -3398,7 +3417,7 @@ int unshare_files(void)
struct files_struct *old, *copy = NULL;
int error;
- error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, &copy);
+ error = unshare_fd(CLONE_FILES, &copy);
if (error || !copy)
return error;
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