Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/open.c b/fs/open.c
index 0285ce7..b62f5c0 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/open.c
*
@@ -373,6 +374,25 @@
override_cred->cap_permitted;
}
+ /*
+ * The new set of credentials can *only* be used in
+ * task-synchronous circumstances, and does not need
+ * RCU freeing, unless somebody then takes a separate
+ * reference to it.
+ *
+ * NOTE! This is _only_ true because this credential
+ * is used purely for override_creds() that installs
+ * it as the subjective cred. Other threads will be
+ * accessing ->real_cred, not the subjective cred.
+ *
+ * If somebody _does_ make a copy of this (using the
+ * 'get_current_cred()' function), that will clear the
+ * non_rcu field, because now that other user may be
+ * expecting RCU freeing. But normal thread-synchronous
+ * cred accesses will keep things non-RCY.
+ */
+ override_cred->non_rcu = 1;
+
old_cred = override_creds(override_cred);
retry:
res = user_path_at(dfd, filename, lookup_flags, &path);
@@ -733,6 +753,12 @@
return 0;
}
+ /* Any file opened for execve()/uselib() has to be a regular file. */
+ if (unlikely(f->f_flags & FMODE_EXEC && !S_ISREG(inode->i_mode))) {
+ error = -EACCES;
+ goto cleanup_file;
+ }
+
if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
error = get_write_access(inode);
if (unlikely(error))
@@ -750,7 +776,7 @@
f->f_mode |= FMODE_ATOMIC_POS;
f->f_op = fops_get(inode->i_fop);
- if (unlikely(WARN_ON(!f->f_op))) {
+ if (WARN_ON(!f->f_op)) {
error = -ENODEV;
goto cleanup_all;
}
@@ -792,6 +818,14 @@
if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
return -EINVAL;
}
+
+ /*
+ * XXX: Huge page cache doesn't support writing yet. Drop all page
+ * cache for this file before processing writes.
+ */
+ if ((f->f_mode & FMODE_WRITE) && filemap_nr_thps(inode->i_mapping))
+ truncate_pagecache(inode, 0);
+
return 0;
cleanup_all:
@@ -1209,3 +1243,22 @@
}
EXPORT_SYMBOL(nonseekable_open);
+
+/*
+ * stream_open is used by subsystems that want stream-like file descriptors.
+ * Such file descriptors are not seekable and don't have notion of position
+ * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
+ * Contrary to file descriptors of other regular files, .read() and .write()
+ * can run simultaneously.
+ *
+ * stream_open never fails and is marked to return int so that it could be
+ * directly used as file_operations.open .
+ */
+int stream_open(struct inode *inode, struct file *filp)
+{
+ filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
+ filp->f_mode |= FMODE_STREAM;
+ return 0;
+}
+
+EXPORT_SYMBOL(stream_open);