diff options
| author | Matthew Wilcox <willy@infradead.org> | 2019-04-06 00:02:10 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-11 13:22:45 +0300 |
| commit | 9557090582a33801349f0a0920a55d134a27e740 (patch) | |
| tree | b00054a031b80755978735b44bc6e0ad017a1859 /fs | |
| parent | 6f3433c47e8223c97746ad227d1e6f5531e0758a (diff) | |
| download | linux-9557090582a33801349f0a0920a55d134a27e740.tar.xz | |
fs: prevent page refcount overflow in pipe_buf_get
commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb upstream.
Change pipe_buf_get() to return a bool indicating whether it succeeded
in raising the refcount of the page (if the thing in the pipe is a page).
This removes another mechanism for overflowing the page refcount. All
callers converted to handle a failure.
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fuse/dev.c | 12 | ||||
| -rw-r--r-- | fs/pipe.c | 4 | ||||
| -rw-r--r-- | fs/splice.c | 12 |
3 files changed, 18 insertions, 10 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 411f16101d1a..eaedbc1a3e95 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1975,10 +1975,8 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; ret = -EINVAL; - if (rem < len) { - pipe_unlock(pipe); - goto out; - } + if (rem < len) + goto out_free; rem = len; while (rem) { @@ -1996,7 +1994,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); pipe->nrbufs--; } else { - pipe_buf_get(pipe, ibuf); + if (!pipe_buf_get(pipe, ibuf)) + goto out_free; + *obuf = *ibuf; obuf->flags &= ~PIPE_BUF_FLAG_GIFT; obuf->len = rem; @@ -2019,11 +2019,11 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, ret = fuse_dev_do_write(fud, &cs, len); pipe_lock(pipe); +out_free: for (idx = 0; idx < nbuf; idx++) pipe_buf_release(pipe, &bufs[idx]); pipe_unlock(pipe); -out: kfree(bufs); return ret; } diff --git a/fs/pipe.c b/fs/pipe.c index 388e09a689de..347c6dc888c8 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -193,9 +193,9 @@ EXPORT_SYMBOL(generic_pipe_buf_steal); * in the tee() system call, when we duplicate the buffers in one * pipe into another. */ -void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) +bool generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - get_page(buf->page); + return try_get_page(buf->page); } EXPORT_SYMBOL(generic_pipe_buf_get); diff --git a/fs/splice.c b/fs/splice.c index 01983bea760c..8bfbc8a50164 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1585,7 +1585,11 @@ retry: * Get a reference to this pipe buffer, * so we can copy the contents over. */ - pipe_buf_get(ipipe, ibuf); + if (!pipe_buf_get(ipipe, ibuf)) { + if (ret == 0) + ret = -EFAULT; + break; + } *obuf = *ibuf; /* @@ -1659,7 +1663,11 @@ static int link_pipe(struct pipe_inode_info *ipipe, * Get a reference to this pipe buffer, * so we can copy the contents over. */ - pipe_buf_get(ipipe, ibuf); + if (!pipe_buf_get(ipipe, ibuf)) { + if (ret == 0) + ret = -EFAULT; + break; + } obuf = opipe->bufs + nbuf; *obuf = *ibuf; |