From: Amir Goldstein <amir73il@gmail.com> mainline inclusion from mainline-v6.8-rc1 commit ca7ab482401cf0a7497dad05f4918dc64115538b category: feature bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBHLU4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The main callers of do_splice_direct() also call rw_verify_area() for the entire range that is being copied, e.g. by vfs_copy_file_range() or do_sendfile() before calling do_splice_direct(). The only caller that does not have those checks for entire range is ovl_copy_up_file(). In preparation for removing the checks inside do_splice_direct(), add rw_verify_area() call in ovl_copy_up_file(). For extra safety, perform minimal sanity checks from rw_verify_area() for non negative offsets also in the copy up do_splice_direct() loop without calling the file permission hooks. This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-2-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/overlayfs/copy_up.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 75059b830246..b8119520300d 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -230,6 +230,19 @@ static int ovl_copy_fileattr(struct inode *inode, const struct path *old, return ovl_real_fileattr_set(new, &newfa); } +static int ovl_verify_area(loff_t pos, loff_t pos2, loff_t len, loff_t totlen) +{ + loff_t tmp; + + if (WARN_ON_ONCE(pos != pos2)) + return -EIO; + if (WARN_ON_ONCE(pos < 0 || len < 0 || totlen < 0)) + return -EIO; + if (WARN_ON_ONCE(check_add_overflow(pos, len, &tmp))) + return -EIO; + return 0; +} + static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, struct file *new_file, loff_t len) { @@ -244,13 +257,20 @@ static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, int error = 0; ovl_path_lowerdata(dentry, &datapath); - if (WARN_ON(datapath.dentry == NULL)) + if (WARN_ON_ONCE(datapath.dentry == NULL) || + WARN_ON_ONCE(len < 0)) return -EIO; old_file = ovl_path_open(&datapath, O_LARGEFILE | O_RDONLY); if (IS_ERR(old_file)) return PTR_ERR(old_file); + error = rw_verify_area(READ, old_file, &old_pos, len); + if (!error) + error = rw_verify_area(WRITE, new_file, &new_pos, len); + if (error) + goto out_fput; + /* Try to use clone_file_range to clone up within the same fs */ ovl_start_write(dentry); cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0); @@ -309,6 +329,10 @@ static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, } } + error = ovl_verify_area(old_pos, new_pos, this_len, len); + if (error) + break; + ovl_start_write(dentry); bytes = do_splice_direct(old_file, &old_pos, new_file, &new_pos, -- 2.39.2