From 77304d2abac6101f7249754ffdd4421258877ab0 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Mon, 8 Nov 2010 14:39:12 +0100 Subject: block: read i_size with i_size_read() Convert direct reads of an inode's i_size to using i_size_read(). i_size_{read,write} use a seqcount to protect reads from accessing incomple writes. Concurrent i_size_write()s require mutual exclussion to protect the seqcount that is used by i_size_{read,write}. But i_size_read() callers do not need to use additional locking. Signed-off-by: Mike Snitzer Acked-by: NeilBrown Acked-by: Lars Ellenberg Signed-off-by: Jens Axboe --- block/ioctl.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'block/ioctl.c') diff --git a/block/ioctl.c b/block/ioctl.c index d724ceb1d46..38aa194f63e 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -125,7 +125,7 @@ static int blk_ioctl_discard(struct block_device *bdev, uint64_t start, start >>= 9; len >>= 9; - if (start + len > (bdev->bd_inode->i_size >> 9)) + if (start + len > (i_size_read(bdev->bd_inode) >> 9)) return -EINVAL; if (secure) flags |= BLKDEV_DISCARD_SECURE; @@ -307,12 +307,12 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd, ret = blkdev_reread_part(bdev); break; case BLKGETSIZE: - size = bdev->bd_inode->i_size; + size = i_size_read(bdev->bd_inode); if ((size >> 9) > ~0UL) return -EFBIG; return put_ulong(arg, size >> 9); case BLKGETSIZE64: - return put_u64(arg, bdev->bd_inode->i_size); + return put_u64(arg, i_size_read(bdev->bd_inode)); case BLKTRACESTART: case BLKTRACESTOP: case BLKTRACESETUP: -- cgit v1.2.3-70-g09d2 From a014741c0adfb8fb79952939ca087cf03d272bb9 Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Mon, 8 Nov 2010 14:42:40 +0100 Subject: block: ioctl: fix information leak to userland Structure hd_geometry is copied to userland with 4 padding bytes between cylinders and start fields uninitialized on 64-bit platforms. It leads to leaking of contents of kernel stack memory. Currently there is no memset() in real implementations of getgeo() in drivers/block/, so it makes sense to have memset() in blkdev_ioctl(). Signed-off-by: Vasiliy Kulikov Signed-off-by: Jens Axboe --- block/ioctl.c | 1 + 1 file changed, 1 insertion(+) (limited to 'block/ioctl.c') diff --git a/block/ioctl.c b/block/ioctl.c index 38aa194f63e..3d866d0037f 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -242,6 +242,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd, * We need to set the startsect first, the driver may * want to override it. */ + memset(&geo, 0, sizeof(geo)); geo.start = get_start_sect(bdev); ret = disk->fops->getgeo(bdev, &geo); if (ret) -- cgit v1.2.3-70-g09d2