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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-28 15:40:55 +0000
committerDavid S. Miller <davem@davemloft.net>2010-10-30 16:34:16 -0700
commit1b1f693d7ad6d193862dcb1118540a030c5e761f (patch)
treecf216d1bfb8a51f3df2c989dcffd5381a0e446f1
parentbdfa3d8fe123a940be121daf374581727b3b6547 (diff)
downloadlinux-linaro-1b1f693d7ad6d193862dcb1118540a030c5e761f.tar.gz
net: fix rds_iovec page count overflow
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>
-rw-r--r--net/rds/rdma.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 1a41debca1c..0df02c8a853 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -502,6 +502,13 @@ static int rds_rdma_pages(struct rds_rdma_args *args)
return -EINVAL;
tot_pages += nr_pages;
+
+ /*
+ * nr_pages for one entry is limited to (UINT_MAX>>PAGE_SHIFT)+1,
+ * so tot_pages cannot overflow without first going negative.
+ */
+ if ((int)tot_pages < 0)
+ return -EINVAL;
}
return tot_pages;