Commit 28a625cb authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: fix pipe_buf_operations



Having this struct in module memory could Oops when if the module is
unloaded while the buffer still persists in a pipe.

Since sock_pipe_buf_ops is essentially the same as fuse_dev_pipe_buf_steal
merge them into nosteal_pipe_buf_ops (this is the same as
default_pipe_buf_ops except stealing the page from the buffer is not
allowed).
Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
parent d8ec26d7
......@@ -1296,22 +1296,6 @@ static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
}
static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return 1;
}
static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
.can_merge = 0,
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
.release = generic_pipe_buf_release,
.steal = fuse_dev_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len, unsigned int flags)
......@@ -1358,7 +1342,11 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
buf->page = bufs[page_nr].page;
buf->offset = bufs[page_nr].offset;
buf->len = bufs[page_nr].len;
buf->ops = &fuse_dev_pipe_buf_ops;
/*
* Need to be careful about this. Having buf->ops in module
* code can Oops if the buffer persists after module unload.
*/
buf->ops = &nosteal_pipe_buf_ops;
pipe->nrbufs++;
page_nr++;
......
......@@ -555,6 +555,24 @@ static const struct pipe_buf_operations default_pipe_buf_ops = {
.get = generic_pipe_buf_get,
};
static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return 1;
}
/* Pipe buffer operations for a socket and similar. */
const struct pipe_buf_operations nosteal_pipe_buf_ops = {
.can_merge = 0,
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
.release = generic_pipe_buf_release,
.steal = generic_pipe_buf_nosteal,
.get = generic_pipe_buf_get,
};
EXPORT_SYMBOL(nosteal_pipe_buf_ops);
static ssize_t kernel_readv(struct file *file, const struct iovec *vec,
unsigned long vlen, loff_t offset)
{
......
......@@ -157,6 +157,8 @@ int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);
int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
extern const struct pipe_buf_operations nosteal_pipe_buf_ops;
/* for F_SETPIPE_SZ and F_GETPIPE_SZ */
long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
struct pipe_inode_info *get_pipe_info(struct file *file);
......
......@@ -74,36 +74,6 @@
struct kmem_cache *skbuff_head_cache __read_mostly;
static struct kmem_cache *skbuff_fclone_cache __read_mostly;
static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
put_page(buf->page);
}
static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
get_page(buf->page);
}
static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return 1;
}
/* Pipe buffer operations for a socket. */
static const struct pipe_buf_operations sock_pipe_buf_ops = {
.can_merge = 0,
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
.release = sock_pipe_buf_release,
.steal = sock_pipe_buf_steal,
.get = sock_pipe_buf_get,
};
/**
* skb_panic - private function for out-of-line support
* @skb: buffer
......@@ -1830,7 +1800,7 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
.partial = partial,
.nr_pages_max = MAX_SKB_FRAGS,
.flags = flags,
.ops = &sock_pipe_buf_ops,
.ops = &nosteal_pipe_buf_ops,
.spd_release = sock_spd_release,
};
struct sk_buff *frag_iter;
......
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