tree 9149a23ed7221737884835aee397687ec5523f92
parent 1350a4cdfbe655967a11a632ce910b97af28cfc7
author Darrick J. Wong <djwong@kernel.org> 1660932871 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1661420448 +0200

xfs: reject crazy array sizes being fed to XFS_IOC_GETBMAP*

[ Upstream commit 29d650f7e3ab55283b89c9f5883d0c256ce478b5 ]

Syzbot tripped over the following complaint from the kernel:

WARNING: CPU: 2 PID: 15402 at mm/util.c:597 kvmalloc_node+0x11e/0x125 mm/util.c:597

While trying to run XFS_IOC_GETBMAP against the following structure:

struct getbmap fubar = {
	.bmv_count	= 0x22dae649,
};

Obviously, this is a crazy huge value since the next thing that the
ioctl would do is allocate 37GB of memory.  This is enough to make
kvmalloc mad, but isn't large enough to trip the validation functions.
In other words, I'm fussing with checks that were **already sufficient**
because that's easier than dealing with 644 internal bug reports.  Yes,
that's right, six hundred and forty-four.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Catherine Hoang <catherine.hoang@oracle.com>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>