From 50f7c4c967d0b5acd8e7ba6ab654dc4a7ac869ac Mon Sep 17 00:00:00 2001 From: Xi Wang Date: Fri, 20 Apr 2012 15:49:44 -0500 Subject: [PATCH] rbd: fix integer overflow in rbd_header_from_disk() ondisk->snap_count is read from disk via rbd_req_sync_read() and thus needs validation. Otherwise, a bogus `snap_count' could overflow the kmalloc() size, leading to memory corruption. Also use `u32' consistently for `snap_count'. [elder@dreamhost.com: changed to use UINT_MAX rather than ULONG_MAX] Signed-off-by: Xi Wang Reviewed-by: Alex Elder --- drivers/block/rbd.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index ca59d4d9471..a75fe93a25b 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -487,16 +487,18 @@ static void rbd_coll_release(struct kref *kref) */ static int rbd_header_from_disk(struct rbd_image_header *header, struct rbd_image_header_ondisk *ondisk, - int allocated_snaps, + u32 allocated_snaps, gfp_t gfp_flags) { - int i; - u32 snap_count; + u32 i, snap_count; if (memcmp(ondisk, RBD_HEADER_TEXT, sizeof(RBD_HEADER_TEXT))) return -ENXIO; snap_count = le32_to_cpu(ondisk->snap_count); + if (snap_count > (UINT_MAX - sizeof(struct ceph_snap_context)) + / sizeof (*ondisk)) + return -EINVAL; header->snapc = kmalloc(sizeof(struct ceph_snap_context) + snap_count * sizeof (*ondisk), gfp_flags); @@ -1591,7 +1593,7 @@ static int rbd_read_header(struct rbd_device *rbd_dev, { ssize_t rc; struct rbd_image_header_ondisk *dh; - int snap_count = 0; + u32 snap_count = 0; u64 ver; size_t len; -- 2.20.1