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bd9ca962ee
commit 7d83fb14258b9961920cd86f0b921caaeb3ebe85 upstream.
During the "insert range" fallocate operation, i_size grows by the
specified 'len' bytes. XFS verifies that i_size + len < s_maxbytes, as
it should. But this comparison is done using the signed 'loff_t', and
'i_size + len' can wrap around to a negative value, causing the check to
incorrectly pass, resulting in an inode with "negative" i_size. This is
possible on 64-bit platforms, where XFS sets s_maxbytes = LLONG_MAX.
ext4 and f2fs don't run into this because they set a smaller s_maxbytes.
Fix it by using subtraction instead.
Reproducer:
xfs_io -f file -c "truncate $(((1<<63)-1))" -c "finsert 0 4096"
Fixes: a904b1ca5751 ("xfs: Add support FALLOC_FL_INSERT_RANGE for fallocate")
Cc: <stable@vger.kernel.org> # v4.1+
Originally-From: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: fix signed integer addition overflow too]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.