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authorMiklos Szeredi <mszeredi@suse.cz>2014-01-22 22:36:57 +0400
committerMiklos Szeredi <mszeredi@suse.cz>2014-01-22 22:36:57 +0400
commit28a625cbc2a14f17b83e47ef907b2658576a32aa (patch)
tree58d461b91f25a6499bd6404cd79faa4f9c185ff0 /fs
parentd8ec26d7f8287f5788a494f56e8814210f0e64be (diff)
downloadlinux-28a625cbc2a14f17b83e47ef907b2658576a32aa.tar.xz
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: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs')
-rw-r--r--fs/fuse/dev.c22
-rw-r--r--fs/splice.c18
2 files changed, 23 insertions, 17 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ef74ad5fd362..fa8cb4b7b8fe 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -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++;
diff --git a/fs/splice.c b/fs/splice.c
index 46a08f772d7d..12028fa41def 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -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)
{