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Subject[34-longterm 156/209] fuse: verify ioctl retries
Date
From: Miklos Szeredi <mszeredi@suse.cz>

=====================================================================
| This is a commit scheduled for the next v2.6.34 longterm release. |
| If you see a problem with using this for longterm, please comment.|
=====================================================================

commit 7572777eef78ebdee1ecb7c258c0ef94d35bad16 upstream.

Verify that the total length of the iovec returned in FUSE_IOCTL_RETRY
doesn't overflow iov_length().

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Tejun Heo <tj@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
fs/fuse/file.c | 22 ++++++++++++++++++++++
1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index cbd2214..db2814f 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1619,6 +1619,20 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
return 0;
}

+/* Make sure iov_length() won't overflow */
+static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
+{
+ size_t n;
+ u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
+
+ for (n = 0; n < count; n++) {
+ if (iov->iov_len > (size_t) max)
+ return -ENOMEM;
+ max -= iov->iov_len;
+ }
+ return 0;
+}
+
/*
* For ioctls, there is no generic way to determine how much memory
* needs to be read and/or written. Furthermore, ioctls are allowed
@@ -1812,6 +1826,14 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
in_iov = page_address(iov_page);
out_iov = in_iov + in_iovs;

+ err = fuse_verify_ioctl_iov(in_iov, in_iovs);
+ if (err)
+ goto out;
+
+ err = fuse_verify_ioctl_iov(out_iov, out_iovs);
+ if (err)
+ goto out;
+
goto retry;
}

--
1.7.4.4


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