Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/fs/file.c b/fs/file.c
index e5d3283..79a76d0 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -10,6 +10,7 @@
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fs.h>
+#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
@@ -18,6 +19,8 @@
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
+#include <linux/close_range.h>
+#include <net/sock.h>
unsigned int sysctl_nr_open __read_mostly = 1024*1024;
unsigned int sysctl_nr_open_min = BITS_PER_LONG;
@@ -264,12 +267,22 @@
return i;
}
+static unsigned int sane_fdtable_size(struct fdtable *fdt, unsigned int max_fds)
+{
+ unsigned int count;
+
+ count = count_open_files(fdt);
+ if (max_fds < NR_OPEN_DEFAULT)
+ max_fds = NR_OPEN_DEFAULT;
+ return min(count, max_fds);
+}
+
/*
* Allocate a new files structure and copy contents from the
* passed in files structure.
* errorp will be valid only when the returned files_struct is NULL.
*/
-struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
+struct files_struct *dup_fd(struct files_struct *oldf, unsigned int max_fds, int *errorp)
{
struct files_struct *newf;
struct file **old_fds, **new_fds;
@@ -296,7 +309,7 @@
spin_lock(&oldf->file_lock);
old_fdt = files_fdtable(oldf);
- open_files = count_open_files(old_fdt);
+ open_files = sane_fdtable_size(old_fdt, max_fds);
/*
* Check whether we need to allocate a larger fd array and fd set.
@@ -327,7 +340,7 @@
*/
spin_lock(&oldf->file_lock);
old_fdt = files_fdtable(oldf);
- open_files = count_open_files(old_fdt);
+ open_files = sane_fdtable_size(old_fdt, max_fds);
}
copy_fd_bitmaps(new_fdt, old_fdt, open_files);
@@ -540,9 +553,14 @@
return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags);
}
+int __get_unused_fd_flags(unsigned flags, unsigned long nofile)
+{
+ return __alloc_fd(current->files, 0, nofile, flags);
+}
+
int get_unused_fd_flags(unsigned flags)
{
- return __alloc_fd(current->files, 0, rlimit(RLIMIT_NOFILE), flags);
+ return __get_unused_fd_flags(flags, rlimit(RLIMIT_NOFILE));
}
EXPORT_SYMBOL(get_unused_fd_flags);
@@ -608,6 +626,10 @@
rcu_read_unlock_sched();
}
+/*
+ * This consumes the "file" refcount, so callers should treat it
+ * as if they had called fput(file).
+ */
void fd_install(unsigned int fd, struct file *file)
{
__fd_install(current->files, fd, file);
@@ -615,12 +637,9 @@
EXPORT_SYMBOL(fd_install);
-/*
- * The same warnings as for __alloc_fd()/__fd_install() apply here...
- */
-int __close_fd(struct files_struct *files, unsigned fd)
+static struct file *pick_file(struct files_struct *files, unsigned fd)
{
- struct file *file;
+ struct file *file = NULL;
struct fdtable *fdt;
spin_lock(&files->file_lock);
@@ -632,17 +651,109 @@
goto out_unlock;
rcu_assign_pointer(fdt->fd[fd], NULL);
__put_unused_fd(files, fd);
- spin_unlock(&files->file_lock);
- return filp_close(file, files);
out_unlock:
spin_unlock(&files->file_lock);
- return -EBADF;
+ return file;
+}
+
+/*
+ * The same warnings as for __alloc_fd()/__fd_install() apply here...
+ */
+int __close_fd(struct files_struct *files, unsigned fd)
+{
+ struct file *file;
+
+ file = pick_file(files, fd);
+ if (!file)
+ return -EBADF;
+
+ return filp_close(file, files);
}
EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
+/**
+ * __close_range() - Close all file descriptors in a given range.
+ *
+ * @fd: starting file descriptor to close
+ * @max_fd: last file descriptor to close
+ *
+ * This closes a range of file descriptors. All file descriptors
+ * from @fd up to and including @max_fd are closed.
+ */
+int __close_range(unsigned fd, unsigned max_fd, unsigned int flags)
+{
+ unsigned int cur_max;
+ struct task_struct *me = current;
+ struct files_struct *cur_fds = me->files, *fds = NULL;
+
+ if (flags & ~CLOSE_RANGE_UNSHARE)
+ return -EINVAL;
+
+ if (fd > max_fd)
+ return -EINVAL;
+
+ rcu_read_lock();
+ cur_max = files_fdtable(cur_fds)->max_fds;
+ rcu_read_unlock();
+
+ /* cap to last valid index into fdtable */
+ cur_max--;
+
+ if (flags & CLOSE_RANGE_UNSHARE) {
+ int ret;
+ unsigned int max_unshare_fds = NR_OPEN_MAX;
+
+ /*
+ * If the requested range is greater than the current maximum,
+ * we're closing everything so only copy all file descriptors
+ * beneath the lowest file descriptor.
+ */
+ if (max_fd >= cur_max)
+ max_unshare_fds = fd;
+
+ ret = unshare_fd(CLONE_FILES, max_unshare_fds, &fds);
+ if (ret)
+ return ret;
+
+ /*
+ * We used to share our file descriptor table, and have now
+ * created a private one, make sure we're using it below.
+ */
+ if (fds)
+ swap(cur_fds, fds);
+ }
+
+ max_fd = min(max_fd, cur_max);
+ while (fd <= max_fd) {
+ struct file *file;
+
+ file = pick_file(cur_fds, fd++);
+ if (!file)
+ continue;
+
+ filp_close(file, cur_fds);
+ cond_resched();
+ }
+
+ if (fds) {
+ /*
+ * We're done closing the files we were supposed to. Time to install
+ * the new file descriptor table and drop the old one.
+ */
+ task_lock(me);
+ me->files = cur_fds;
+ task_unlock(me);
+ put_files_struct(fds);
+ }
+
+ return 0;
+}
+
/*
- * variant of __close_fd that gets a ref on the file for later fput
+ * variant of __close_fd that gets a ref on the file for later fput.
+ * The caller must ensure that filp_close() called on the file, and then
+ * an fput().
*/
int __close_fd_get_file(unsigned int fd, struct file **res)
{
@@ -662,7 +773,7 @@
spin_unlock(&files->file_lock);
get_file(file);
*res = file;
- return filp_close(file, files);
+ return 0;
out_unlock:
spin_unlock(&files->file_lock);
@@ -706,29 +817,79 @@
spin_unlock(&files->file_lock);
}
-static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs)
+static inline struct file *__fget_files_rcu(struct files_struct *files,
+ unsigned int fd, fmode_t mask, unsigned int refs)
{
- struct files_struct *files = current->files;
+ for (;;) {
+ struct file *file;
+ struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+ struct file __rcu **fdentry;
+
+ if (unlikely(fd >= fdt->max_fds))
+ return NULL;
+
+ fdentry = fdt->fd + array_index_nospec(fd, fdt->max_fds);
+ file = rcu_dereference_raw(*fdentry);
+ if (unlikely(!file))
+ return NULL;
+
+ if (unlikely(file->f_mode & mask))
+ return NULL;
+
+ /*
+ * Ok, we have a file pointer. However, because we do
+ * this all locklessly under RCU, we may be racing with
+ * that file being closed.
+ *
+ * Such a race can take two forms:
+ *
+ * (a) the file ref already went down to zero,
+ * and get_file_rcu_many() fails. Just try
+ * again:
+ */
+ if (unlikely(!get_file_rcu_many(file, refs)))
+ continue;
+
+ /*
+ * (b) the file table entry has changed under us.
+ * Note that we don't need to re-check the 'fdt->fd'
+ * pointer having changed, because it always goes
+ * hand-in-hand with 'fdt'.
+ *
+ * If so, we need to put our refs and try again.
+ */
+ if (unlikely(rcu_dereference_raw(files->fdt) != fdt) ||
+ unlikely(rcu_dereference_raw(*fdentry) != file)) {
+ fput_many(file, refs);
+ continue;
+ }
+
+ /*
+ * Ok, we have a ref to the file, and checked that it
+ * still exists.
+ */
+ return file;
+ }
+}
+
+static struct file *__fget_files(struct files_struct *files, unsigned int fd,
+ fmode_t mask, unsigned int refs)
+{
struct file *file;
rcu_read_lock();
-loop:
- file = fcheck_files(files, fd);
- if (file) {
- /* File object ref couldn't be taken.
- * dup2() atomicity guarantee is the reason
- * we loop to catch the new file (or NULL pointer)
- */
- if (file->f_mode & mask)
- file = NULL;
- else if (!get_file_rcu_many(file, refs))
- goto loop;
- }
+ file = __fget_files_rcu(files, fd, mask, refs);
rcu_read_unlock();
return file;
}
+static inline struct file *__fget(unsigned int fd, fmode_t mask,
+ unsigned int refs)
+{
+ return __fget_files(current->files, fd, mask, refs);
+}
+
struct file *fget_many(unsigned int fd, unsigned int refs)
{
return __fget(fd, FMODE_PATH, refs);
@@ -746,6 +907,18 @@
}
EXPORT_SYMBOL(fget_raw);
+struct file *fget_task(struct task_struct *task, unsigned int fd)
+{
+ struct file *file = NULL;
+
+ task_lock(task);
+ if (task->files)
+ file = __fget_files(task->files, fd, 0, 1);
+ task_unlock(task);
+
+ return file;
+}
+
/*
* Lightweight file lookup - no refcnt increment if fd table isn't shared.
*
@@ -906,6 +1079,62 @@
return err;
}
+/**
+ * __receive_fd() - Install received file into file descriptor table
+ *
+ * @fd: fd to install into (if negative, a new fd will be allocated)
+ * @file: struct file that was received from another process
+ * @ufd: __user pointer to write new fd number to
+ * @o_flags: the O_* flags to apply to the new fd entry
+ *
+ * Installs a received file into the file descriptor table, with appropriate
+ * checks and count updates. Optionally writes the fd number to userspace, if
+ * @ufd is non-NULL.
+ *
+ * This helper handles its own reference counting of the incoming
+ * struct file.
+ *
+ * Returns newly install fd or -ve on error.
+ */
+int __receive_fd(int fd, struct file *file, int __user *ufd, unsigned int o_flags)
+{
+ int new_fd;
+ int error;
+
+ error = security_file_receive(file);
+ if (error)
+ return error;
+
+ if (fd < 0) {
+ new_fd = get_unused_fd_flags(o_flags);
+ if (new_fd < 0)
+ return new_fd;
+ } else {
+ new_fd = fd;
+ }
+
+ if (ufd) {
+ error = put_user(new_fd, ufd);
+ if (error) {
+ if (fd < 0)
+ put_unused_fd(new_fd);
+ return error;
+ }
+ }
+
+ if (fd < 0) {
+ fd_install(new_fd, get_file(file));
+ } else {
+ error = replace_fd(new_fd, file, o_flags);
+ if (error)
+ return error;
+ }
+
+ /* Bump the sock usage counts, if any. */
+ __receive_sock(file);
+ return new_fd;
+}
+
static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
{
int err = -EBADF;
@@ -960,7 +1189,7 @@
return ksys_dup3(oldfd, newfd, 0);
}
-int ksys_dup(unsigned int fildes)
+SYSCALL_DEFINE1(dup, unsigned int, fildes)
{
int ret = -EBADF;
struct file *file = fget_raw(fildes);
@@ -975,11 +1204,6 @@
return ret;
}
-SYSCALL_DEFINE1(dup, unsigned int, fildes)
-{
- return ksys_dup(fildes);
-}
-
int f_dupfd(unsigned int from, struct file *file, unsigned flags)
{
int err;