From: Amir Goldstein <amir73il@gmail.com> mainline inclusion from mainline-v6.8-rc1 commit 1c8aa833034a00617866ea4738a40491e3e23902 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... -------------------------------- In many of the vfs helpers, the rw_verity_area() checks are called before taking sb_start_write(), making them "start-write-safe". do_iter_write() is an exception to this rule. do_iter_write() has two callers - vfs_iter_write() and vfs_writev(). Move rw_verify_area() and other checks from do_iter_write() out to its callers to make them "start-write-safe". Move also the fsnotify_modify() hook to align with similar pattern used in vfs_write() and other vfs helpers. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-12-amir73il@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/read_write.c | 86 +++++++++++++++++++++++++++---------------------- 1 file changed, 48 insertions(+), 38 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index be8e05e8aa7f..dd1457b9209a 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -840,33 +840,6 @@ ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos, } EXPORT_SYMBOL(vfs_iter_read); -static ssize_t do_iter_write(struct file *file, struct iov_iter *iter, - loff_t *pos, rwf_t flags) -{ - size_t tot_len; - ssize_t ret = 0; - - if (!(file->f_mode & FMODE_WRITE)) - return -EBADF; - if (!(file->f_mode & FMODE_CAN_WRITE)) - return -EINVAL; - - tot_len = iov_iter_count(iter); - if (!tot_len) - return 0; - ret = rw_verify_area(WRITE, file, pos, tot_len); - if (ret < 0) - return ret; - - if (file->f_op->write_iter) - ret = do_iter_readv_writev(file, iter, pos, WRITE, flags); - else - ret = do_loop_readv_writev(file, iter, pos, WRITE, flags); - if (ret > 0) - fsnotify_modify(file); - return ret; -} - ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb, struct iov_iter *iter) { @@ -898,13 +871,28 @@ EXPORT_SYMBOL(vfs_iocb_iter_write); ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos, rwf_t flags) { - int ret; + size_t tot_len; + ssize_t ret; + if (!(file->f_mode & FMODE_WRITE)) + return -EBADF; + if (!(file->f_mode & FMODE_CAN_WRITE)) + return -EINVAL; if (!file->f_op->write_iter) return -EINVAL; + tot_len = iov_iter_count(iter); + if (!tot_len) + return 0; + + ret = rw_verify_area(WRITE, file, ppos, tot_len); + if (ret < 0) + return ret; + file_start_write(file); - ret = do_iter_write(file, iter, ppos, flags); + ret = do_iter_readv_writev(file, iter, ppos, WRITE, flags); + if (ret > 0) + fsnotify_modify(file); file_end_write(file); return ret; @@ -929,20 +917,42 @@ static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, } static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, - unsigned long vlen, loff_t *pos, rwf_t flags) + unsigned long vlen, loff_t *pos, rwf_t flags) { struct iovec iovstack[UIO_FASTIOV]; struct iovec *iov = iovstack; struct iov_iter iter; - ssize_t ret; + size_t tot_len; + ssize_t ret = 0; - ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); - if (ret >= 0) { - file_start_write(file); - ret = do_iter_write(file, &iter, pos, flags); - file_end_write(file); - kfree(iov); - } + if (!(file->f_mode & FMODE_WRITE)) + return -EBADF; + if (!(file->f_mode & FMODE_CAN_WRITE)) + return -EINVAL; + + ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov, + &iter); + if (ret < 0) + return ret; + + tot_len = iov_iter_count(&iter); + if (!tot_len) + goto out; + + ret = rw_verify_area(WRITE, file, pos, tot_len); + if (ret < 0) + goto out; + + file_start_write(file); + if (file->f_op->write_iter) + ret = do_iter_readv_writev(file, &iter, pos, WRITE, flags); + else + ret = do_loop_readv_writev(file, &iter, pos, WRITE, flags); + if (ret > 0) + fsnotify_modify(file); + file_end_write(file); +out: + kfree(iov); return ret; } -- 2.39.2