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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-28 15:40:55 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-14 16:53:15 -0700
commitb291661643c93044e6d4a228d3268649ccf30a0c (patch)
tree149c626e9fe1d24ef386f00783b34b506cbc6186
parentf4cee52eb81b6a8893f6f52e3b9d952ed0dbcbf6 (diff)
downloadlinux-linaro-stable-b291661643c93044e6d4a228d3268649ccf30a0c.tar.gz
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/rds/rdma.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 1fa0f4b9fac3..4810a25a53c7 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -497,6 +497,14 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
max_pages = max(nr, max_pages);
nr_pages += nr;
+
+ /*
+ * nr_pages for one entry is limited to (UINT_MAX>>PAGE_SHIFT)+1,
+ * so tot_pages cannot overflow without first going negative.
+ */
+ if ((int)nr_pages < 0)
+ ret = -EINVAL;
+ goto out;
}
pages = kcalloc(max_pages, sizeof(struct page *), GFP_KERNEL);