[3.8.y.z extended stable] Patch "fuse: fix pipe_buf_operations" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Fri Feb 7 21:37:13 UTC 2014
This is a note to let you know that I have just added a patch titled
fuse: fix pipe_buf_operations
to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue
This patch is scheduled to be released in version 3.8.13.18.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From cecc4ea36624bc286cbd41a03c1776e1568dc1b9 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi at suse.cz>
Date: Wed, 22 Jan 2014 19:36:57 +0100
Subject: fuse: fix pipe_buf_operations
commit 28a625cbc2a14f17b83e47ef907b2658576a32aa upstream.
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: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi at suse.cz>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
fs/fuse/dev.c | 22 +++++-----------------
fs/splice.c | 18 ++++++++++++++++++
include/linux/pipe_fs_i.h | 2 ++
net/core/skbuff.c | 32 +-------------------------------
4 files changed, 26 insertions(+), 48 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index e83351a..1101b04 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1193,22 +1193,6 @@ 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)
@@ -1255,7 +1239,11 @@ 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++;
diff --git a/fs/splice.c b/fs/splice.c
index 6909d89..d375a58 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -553,6 +553,24 @@ 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)
{
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index ad1a427..8f34044 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -156,6 +156,8 @@ 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);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 32443eb..cdcb448 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -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,
-};
-
/*
* Keep out-of-line to prevent kernel bloat.
* __builtin_return_address is not used because it is not always
@@ -1796,7 +1766,7 @@ 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;
--
1.8.3.2
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