From: Frank Sorenson <sorenson@redhat.com> stable inclusion from stable-6.6.157 commit 7f62817fe049b0f3652518c1ba72631ec1e0a322 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18924 CVE: CVE-2026-89640 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------ commit 6c322f5cf7476ded7a9a20f7be72462065a03c68 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Lu Jialin <lujialin4@huawei.com> --- fs/smb/client/cifsfs.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c index 4d5f3a2c8e50..c19e7d16a13a 100644 --- a/fs/smb/client/cifsfs.c +++ b/fs/smb/client/cifsfs.c @@ -1327,8 +1327,19 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, */ 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, "clone range\n"); -- 2.34.1