From b8e1425bae856b189e2365ff795e30fdd9e77049 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Sun, 16 Jul 2023 14:47:14 +0300 Subject: [PATCH] fs: move permission hook out of do_iter_read() We recently moved fsnotify hook, rw_verify_area() and other checks from do_iter_write() out to its two callers. for consistency, do the same thing for do_iter_read() - move the rw_verify_area() checks and fsnotify hook to the callers vfs_iter_read() and vfs_readv(). This aligns those vfs helpers with the pattern used in vfs_read() and vfs_iocb_iter_read() and the vfs write helpers, where all the checks are in the vfs helpers and the do_* or call_* helpers do the work. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara Reviewed-by: Josef Bacik Signed-off-by: Amir Goldstein Link: https://lore.kernel.org/r/20231122122715.2561213-13-amir73il@gmail.com Reviewed-by: Jan Kara Signed-off-by: Amir Goldstein Signed-off-by: Christian Brauner --- fs/read_write.c | 86 ++++++++++++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 37 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index d08d0a3ff7de..9fce8d6968df 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -773,34 +773,6 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter, return ret; } -static ssize_t do_iter_read(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_READ)) - return -EBADF; - if (!(file->f_mode & FMODE_CAN_READ)) - return -EINVAL; - - tot_len = iov_iter_count(iter); - if (!tot_len) - goto out; - ret = rw_verify_area(READ, file, pos, tot_len); - if (ret < 0) - return ret; - - if (file->f_op->read_iter) - ret = do_iter_readv_writev(file, iter, pos, READ, flags); - else - ret = do_loop_readv_writev(file, iter, pos, READ, flags); -out: - if (ret >= 0) - fsnotify_access(file); - return ret; -} - ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb, struct iov_iter *iter) { @@ -830,11 +802,30 @@ ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb, EXPORT_SYMBOL(vfs_iocb_iter_read); ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos, - rwf_t flags) + rwf_t flags) { + size_t tot_len; + ssize_t ret = 0; + if (!file->f_op->read_iter) return -EINVAL; - return do_iter_read(file, iter, ppos, flags); + if (!(file->f_mode & FMODE_READ)) + return -EBADF; + if (!(file->f_mode & FMODE_CAN_READ)) + return -EINVAL; + + tot_len = iov_iter_count(iter); + if (!tot_len) + goto out; + ret = rw_verify_area(READ, file, ppos, tot_len); + if (ret < 0) + return ret; + + ret = do_iter_readv_writev(file, iter, ppos, READ, flags); +out: + if (ret >= 0) + fsnotify_access(file); + return ret; } EXPORT_SYMBOL(vfs_iter_read); @@ -898,19 +889,40 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos, EXPORT_SYMBOL(vfs_iter_write); static ssize_t vfs_readv(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_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); - if (ret >= 0) { - ret = do_iter_read(file, &iter, pos, flags); - kfree(iov); - } + if (!(file->f_mode & FMODE_READ)) + return -EBADF; + if (!(file->f_mode & FMODE_CAN_READ)) + return -EINVAL; + ret = import_iovec(ITER_DEST, 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(READ, file, pos, tot_len); + if (ret < 0) + goto out; + + if (file->f_op->read_iter) + ret = do_iter_readv_writev(file, &iter, pos, READ, flags); + else + ret = do_loop_readv_writev(file, &iter, pos, READ, flags); +out: + if (ret >= 0) + fsnotify_access(file); + kfree(iov); return ret; }