From: Zou Wei zou_wei@huawei.com

stable inclusion from stable-v4.19.198 commit 89ce0b0747f319eb70f85bc820dcc43cebbd5417 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4E8 CVE: CVE-2021-47357

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ Upstream commit 1c72e6ab66b9598cac741ed397438a52065a8f1f ]

This module's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.

Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Zou Wei zou_wei@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- drivers/atm/iphase.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/atm/iphase.c b/drivers/atm/iphase.c index 008905d4152a..827c6d5e6177 100644 --- a/drivers/atm/iphase.c +++ b/drivers/atm/iphase.c @@ -3301,7 +3301,7 @@ static void __exit ia_module_exit(void) { pci_unregister_driver(&ia_driver);

- del_timer(&ia_timer); + del_timer_sync(&ia_timer); }

module_init(ia_module_init);