From: Dan Rosenberg Date: Thu, 24 Jun 2010 02:07:47 +0000 (+1000) Subject: xfs: prevent swapext from operating on write-only files X-Git-Tag: v2.6.35-rc4~4^2~4 X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=1817176a86352f65210139d4c794ad2d19fc6b63 xfs: prevent swapext from operating on write-only files [ cve-2010-2266 ] [ cebbert@redhat.com : backport to 2.6.32 ] This patch prevents user "foo" from using the SWAPEXT ioctl to swap a write-only file owned by user "bar" into a file owned by "foo" and subsequently reading it. It does so by checking that the file descriptors passed to the ioctl are also opened for reading. Signed-off-by: Dan Rosenberg Reviewed-by: Christoph Hellwig --- diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c index 5bba29a..7f159d2 100644 --- a/fs/xfs/xfs_dfrag.c +++ b/fs/xfs/xfs_dfrag.c @@ -69,7 +69,9 @@ xfs_swapext( goto out; } - if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND)) { + if (!(file->f_mode & FMODE_WRITE) || + !(file->f_mode & FMODE_READ) || + (file->f_flags & O_APPEND)) { error = XFS_ERROR(EBADF); goto out_put_file; } @@ -81,6 +83,7 @@ xfs_swapext( } if (!(target_file->f_mode & FMODE_WRITE) || + !(target_file->f_mode & FMODE_READ) || (target_file->f_flags & O_APPEND)) { error = XFS_ERROR(EBADF); goto out_put_target_file;