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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-28 15:40:55 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-22 08:44:32 -0700
commitdcef84f17ad3f3b1ab08dce2ffd45f9e5b0f08e0 (patch)
tree4ea96b23df99d66358f3d9a851317aa551b9977d
parentc4f6afb9ce907df438c67b2e5d5ce3e2448b9b38 (diff)
net: fix rds_iovec page count overflow
commit 1b1f693d7ad6d193862dcb1118540a030c5e761f upstream. As reported by Thomas Pollet, the rdma page counting can overflow. We get the rdma sizes in 64-bit unsigned entities, but then limit it to UINT_MAX bytes and shift them down to pages (so with a possible "+1" for an unaligned address). So each individual page count fits comfortably in an 'unsigned int' (not even close to overflowing into signed), but as they are added up, they might end up resulting in a signed return value. Which would be wrong. Catch the case of tot_pages turning negative, and return the appropriate error code. Reported-by: Thomas Pollet <thomas.pollet@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andy Grover <andy.grover@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> [v2: nr is unsigned in the old code] Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Acked-by: Tim Gardner <tim.gardner@canonical.com> Acked-by: Brad Figg <brad.figg@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/rds/rdma.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 6b09b941d3a7..ff5e3c998f58 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -473,6 +473,17 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
max_pages = max(nr, max_pages);
nr_pages += nr;
+
+ /*
+ * nr for one entry in limited to (UINT_MAX>>PAGE_SHIFT)+1
+ * so nr_pages cannot overflow without becoming bigger than
+ * INT_MAX first. If nr cannot overflow then max_pages should
+ * be ok.
+ */
+ if (nr_pages > INT_MAX) {
+ ret = -EINVAL;
+ goto out;
+ }
}
pages = kcalloc(max_pages, sizeof(struct page *), GFP_KERNEL);