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fs: move permission hook out of do_iter_read()

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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 <jack@suse.cz>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-13-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>
This commit is contained in:
Amir Goldstein 2023-07-16 14:47:14 +03:00 committed by Christian Brauner
parent 1c8aa83303
commit b8e1425bae
1 changed files with 49 additions and 37 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

86
fs/read_write.c
View file

@ -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;
}