Re: [PATCH v2] net/rds: Fix a use after free in rds_message_map_pages
From: Haakon Bugge <hidden>
Date: 2021-03-31 18:27:11
Also in:
linux-rdma, lkml
On 31 Mar 2021, at 03:59, Lv Yunlong [off-list ref] wrote:
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 <redacted>Reviewed-by: Håkon Bugge <redacted> Thanks for fixing this:-) Håkon
quoted hunk ↗ jump to hunk
--- net/rds/message.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)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 inrm->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) { -- 2.25.1