This is a note to let you know that I've just added the patch titled
net/rds: Fix a use after free in rds_message_map_pages
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-rds-fix-a-use-after-free-in-rds_message_map_page.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9d973b3ec0fc5dff8c5a34a4349a2f73f498ed71
Author: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
Date: Tue Mar 30 18:59:59 2021 -0700
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@xxxxxxxxxxxxxxxx>
Reviewed-by: HÃ¥kon Bugge <haakon.bugge@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/rds/message.c b/net/rds/message.c
index 2d43e13d6dd5..92b6b22884d4 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) {
