[PATCH 5.4 295/411] firmware: stratix10-svc: fix a missing check on list iterator

Greg Kroah-Hartman
2022-06-13T11:39:47Z

From: Xiaomeng Tong <xiam0nd.tong@gmail.com>

[ Upstream commit 5a0793ac66ac0e254d292f129a4d6c526f9f2aff ]

The bug is here:
pmem->vaddr = NULL;

The list iterator 'pmem' will point to a bogus position containing
HEAD if the list is empty or no element is found. This case must
be checked before any use of the iterator, otherwise it will
lead to a invalid memory access.

To fix this bug, just gen_pool_free/set NULL/list_del() and return
when found, otherwise list_del HEAD and return;

Fixes: 7ca5ce896524f ("firmware: add Intel Stratix10 service layer driver")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220414035609.2239-1-xiam0nd.tong@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/firmware/stratix10-svc.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/firmware/stratix10-svc.c b/drivers/firmware/stratix10-svc.c
index b2b4ba240fb1..08c422380a00 100644
--- a/drivers/firmware/stratix10-svc.c
+++ b/drivers/firmware/stratix10-svc.c
@@ -934,17 +934,17 @@ EXPORT_SYMBOL_GPL(stratix10_svc_allocate_memory);
void stratix10_svc_free_memory(struct stratix10_svc_chan *chan, void *kaddr)
{
struct stratix10_svc_data_mem *pmem;
- size_t size = 0;

list_for_each_entry(pmem, &svc_data_mem, node)
if (pmem->vaddr == kaddr) {
- size = pmem->size;
- break;
+ gen_pool_free(chan->ctrl->genpool,
+ (unsigned long)kaddr, pmem->size);
+ pmem->vaddr = NULL;
+ list_del(&pmem->node);
+ return;
}

- gen_pool_free(chan->ctrl->genpool, (unsigned long)kaddr, size);
- pmem->vaddr = NULL;
- list_del(&pmem->node);
+ list_del(&svc_data_mem);
}
EXPORT_SYMBOL_GPL(stratix10_svc_free_memory);

--
2.35.1