From: Frank Sorenson <sorenson@redhat.com> mainline inclusion from mainline-v7.3-rc1 commit 6c322f5cf7476ded7a9a20f7be72462065a03c68 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18924 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- With len == 0 (clone to EOF), the effective length is computed as: len = src_inode->i_size - off; If off > i_size, this is a negative loff_t, corrupting the ByteCount in the FSCTL_DUPLICATE_EXTENTS_TO_FILE request and inverting the range in filemap_write_and_wait_range(). The existing off >= i_size check fires only after the ioctl has already been sent. Snapshot i_size_read() once for both the bounds check and the length calculation, eliminating the TOCTOU and 32-bit torn-read risk. Reject off > src_size with -EINVAL. Treat off == src_size as a no-op, consistent with __generic_remap_file_range_prep(). Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer") Cc: stable@vger.kernel.org Signed-off-by: Frank Sorenson <sorenson@redhat.com> Reviewed-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Paulo Alcantara <pc@manguebit.org> Conflicts: fs/cifs/cifsfs.c [5.10 keeps this file at fs/cifs/cifsfs.c and its cifs_remap_file_range() has no unlock label, which this fix references; add unlock: right before unlock_two_nondirectories() so the new error and zero-length exits release the locks and still free the xid via the existing out: path.] Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cifs/cifsfs.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index a86a1fb34e59..1d102d8c3ba6 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -1116,12 +1116,23 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, * checks for proper open modes and file type and if it wants * server could even support copy of range where source = target */ lock_two_nondirectories(target_inode, src_inode); - if (len == 0) - len = src_inode->i_size - off; + if (len == 0) { + loff_t src_size = i_size_read(src_inode); + + if (off > src_size) { + rc = -EINVAL; + goto unlock; + } + len = src_size - off; + if (!len) { + rc = 0; + goto unlock; + } + } cifs_dbg(FYI, "about to flush pages\n"); /* should we flush first and last page first */ truncate_inode_pages_range(&target_inode->i_data, destoff, PAGE_ALIGN(destoff + len)-1); @@ -1133,10 +1144,11 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, rc = -EOPNOTSUPP; /* force revalidate of size and timestamps of target file now that target is updated on the server */ CIFS_I(target_inode)->time = 0; +unlock: /* although unlocking in the reverse order from locking is not strictly necessary here it is a little cleaner to be consistent */ unlock_two_nondirectories(src_inode, target_inode); out: free_xid(xid); -- 2.52.0