Commit bdc2ab5c authored by Lv Yunlong's avatar Lv Yunlong Committed by David S. Miller
Browse files

net/rds: Fix a use after free in rds_message_map_pages 



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: 7dba9203 ("net/rds: Use ERR_PTR for rds_message_alloc_sgs()")
Signed-off-by: default avatarLv Yunlong <lyl2019@mail.ustc.edu.cn>
Reviewed-by: default avatarHåkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d47ec7a0

net/rds/message.c

+2 −1
Original line number Diff line number Diff line
@@ -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) {