On 32-bit systems, a large `pglen' would overflow `pglen*sizeof(u32)'
and bypass the check ceph_decode_need(p, end, pglen*sizeof(u32), bad).
It would also overflow the subsequent kmalloc() size, leading to
out-of-bounds write.
Signed-off-by: Xi Wang <xi.wang@xxxxxxxxx>
---
net/ceph/osdmap.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 774eac6..b1ea6d1 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -891,6 +891,10 @@ struct ceph_osdmap *osdmap_apply_incremental(void **p, void *end,
if (pglen) {
/* insert */
+ if (pglen > (UINT_MAX - sizeof(*pg)) / sizeof(u32)) {
+ err = -EINVAL;
+ goto bad;
+ }
ceph_decode_need(p, end, pglen*sizeof(u32), bad);
pg = kmalloc(sizeof(*pg) + sizeof(u32)*pglen, GFP_NOFS);
if (!pg) {
--
1.7.5.4
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