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authorLv Yunlong <lyl2019@mail.ustc.edu.cn>2021-03-30 18:59:59 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-04-14 08:42:09 +0200
commit4cfae7b23889fd7e6af2e371c3d2f5eb7e49de0b (patch)
tree49f004661604e777140214f619c384281ca69f76 /net
parent05bbe9d85a4c2cbf79aea1023fa8ee8330bfe547 (diff)
net/rds: Fix a use after free in rds_message_map_pages
[ Upstream commit bdc2ab5c61a5c07388f4820ff21e787b4dfd1ced ] In rds_message_map_pages, the rm is freed by rds_message_put(rm). But rm is still used by rm->data.op_sg in return value. My patch assigns ERR_CAST(rm->data.op_sg) to err before the rm is freed to avoid the uaf. Fixes: 7dba92037baf3 ("net/rds: Use ERR_PTR for rds_message_alloc_sgs()") Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> Reviewed-by: HÃ¥kon Bugge <haakon.bugge@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/rds/message.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/rds/message.c b/net/rds/message.c
index 071a261fdaab..799034e0f513 100644
--- a/net/rds/message.c
+++ b/net/rds/message.c
@@ -347,8 +347,9 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in
rm->data.op_nents = DIV_ROUND_UP(total_len, PAGE_SIZE);
rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
if (IS_ERR(rm->data.op_sg)) {
+ void *err = ERR_CAST(rm->data.op_sg);
rds_message_put(rm);
- return ERR_CAST(rm->data.op_sg);
+ return err;
}
for (i = 0; i < rm->data.op_nents; ++i) {