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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-10 20:32:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-10 20:32:37 -0700
commit40f06c799539739a08a56be8a096f56aeed05731 (patch)
treeb36fd977d7abaa5041222bd07e600938af28a0d1 /mm/filemap.c
parenta47f5c56b2eb55290e2a8668e9ca9c029990dbf6 (diff)
parentfe0da9c09b2dc448ff781d1426ecb36d145ce51b (diff)
Merge tag 'copy-file-range-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull copy_file_range updates from Darrick Wong: "This fixes numerous parameter checking problems and inconsistent behaviors in the new(ish) copy_file_range system call. Now the system call will actually check its range parameters correctly; refuse to copy into files for which the caller does not have sufficient privileges; update mtime and strip setuid like file writes are supposed to do; and allows copying up to the EOF of the source file instead of failing the call like we used to. Summary: - Create a generic copy_file_range handler and make individual filesystems responsible for calling it (i.e. no more assuming that do_splice_direct will work or is appropriate) - Refactor copy_file_range and remap_range parameter checking where they are the same - Install missing copy_file_range parameter checking(!) - Remove suid/sgid and update mtime like any other file write - Change the behavior so that a copy range crossing the source file's eof will result in a short copy to the source file's eof instead of EINVAL - Permit filesystems to decide if they want to handle cross-superblock copy_file_range in their local handlers" * tag 'copy-file-range-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: fuse: copy_file_range needs to strip setuid bits and update timestamps vfs: allow copy_file_range to copy across devices xfs: use file_modified() helper vfs: introduce file_modified() helper vfs: add missing checks to copy_file_range vfs: remove redundant checks from generic_remap_checks() vfs: introduce generic_file_rw_checks() vfs: no fallback for ->copy_file_range vfs: introduce generic_copy_file_range()
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c110
1 files changed, 89 insertions, 21 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 6dd9a2274c80..01e7e0869bba 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2925,24 +2925,11 @@ EXPORT_SYMBOL(read_cache_page_gfp);
* LFS limits. If pos is under the limit it becomes a short access. If it
* exceeds the limit we return -EFBIG.
*/
-static int generic_access_check_limits(struct file *file, loff_t pos,
- loff_t *count)
-{
- struct inode *inode = file->f_mapping->host;
- loff_t max_size = inode->i_sb->s_maxbytes;
-
- if (!(file->f_flags & O_LARGEFILE))
- max_size = MAX_NON_LFS;
-
- if (unlikely(pos >= max_size))
- return -EFBIG;
- *count = min(*count, max_size - pos);
- return 0;
-}
-
static int generic_write_check_limits(struct file *file, loff_t pos,
loff_t *count)
{
+ struct inode *inode = file->f_mapping->host;
+ loff_t max_size = inode->i_sb->s_maxbytes;
loff_t limit = rlimit(RLIMIT_FSIZE);
if (limit != RLIM_INFINITY) {
@@ -2953,7 +2940,15 @@ static int generic_write_check_limits(struct file *file, loff_t pos,
*count = min(*count, limit - pos);
}
- return generic_access_check_limits(file, pos, count);
+ if (!(file->f_flags & O_LARGEFILE))
+ max_size = MAX_NON_LFS;
+
+ if (unlikely(pos >= max_size))
+ return -EFBIG;
+
+ *count = min(*count, max_size - pos);
+
+ return 0;
}
/*
@@ -2993,7 +2988,7 @@ EXPORT_SYMBOL(generic_write_checks);
/*
* Performs necessary checks before doing a clone.
*
- * Can adjust amount of bytes to clone.
+ * Can adjust amount of bytes to clone via @req_count argument.
* Returns appropriate error code that caller should return or
* zero in case the clone should be allowed.
*/
@@ -3031,10 +3026,6 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in,
return -EINVAL;
count = min(count, size_in - (uint64_t)pos_in);
- ret = generic_access_check_limits(file_in, pos_in, &count);
- if (ret)
- return ret;
-
ret = generic_write_check_limits(file_out, pos_out, &count);
if (ret)
return ret;
@@ -3071,6 +3062,83 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in,
return 0;
}
+
+/*
+ * Performs common checks before doing a file copy/clone
+ * from @file_in to @file_out.
+ */
+int generic_file_rw_checks(struct file *file_in, struct file *file_out)
+{
+ struct inode *inode_in = file_inode(file_in);
+ struct inode *inode_out = file_inode(file_out);
+
+ /* Don't copy dirs, pipes, sockets... */
+ if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
+ return -EISDIR;
+ if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+ return -EINVAL;
+
+ if (!(file_in->f_mode & FMODE_READ) ||
+ !(file_out->f_mode & FMODE_WRITE) ||
+ (file_out->f_flags & O_APPEND))
+ return -EBADF;
+
+ return 0;
+}
+
+/*
+ * Performs necessary checks before doing a file copy
+ *
+ * Can adjust amount of bytes to copy via @req_count argument.
+ * Returns appropriate error code that caller should return or
+ * zero in case the copy should be allowed.
+ */
+int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
+ struct file *file_out, loff_t pos_out,
+ size_t *req_count, unsigned int flags)
+{
+ struct inode *inode_in = file_inode(file_in);
+ struct inode *inode_out = file_inode(file_out);
+ uint64_t count = *req_count;
+ loff_t size_in;
+ int ret;
+
+ ret = generic_file_rw_checks(file_in, file_out);
+ if (ret)
+ return ret;
+
+ /* Don't touch certain kinds of inodes */
+ if (IS_IMMUTABLE(inode_out))
+ return -EPERM;
+
+ if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
+ return -ETXTBSY;
+
+ /* Ensure offsets don't wrap. */
+ if (pos_in + count < pos_in || pos_out + count < pos_out)
+ return -EOVERFLOW;
+
+ /* Shorten the copy to EOF */
+ size_in = i_size_read(inode_in);
+ if (pos_in >= size_in)
+ count = 0;
+ else
+ count = min(count, size_in - (uint64_t)pos_in);
+
+ ret = generic_write_check_limits(file_out, pos_out, &count);
+ if (ret)
+ return ret;
+
+ /* Don't allow overlapped copying within the same file. */
+ if (inode_in == inode_out &&
+ pos_out + count > pos_in &&
+ pos_out < pos_in + count)
+ return -EINVAL;
+
+ *req_count = count;
+ return 0;
+}
+
int pagecache_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)