From: Arthur Kiyanovski Date: Fri, 8 May 2026 06:21:21 +0000 (+0000) Subject: net: ena: PHC: Fix potential use-after-free in get_timestamp X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e42c755582f0960e684298762f0ab927b3778376;p=thirdparty%2Fkernel%2Flinux.git net: ena: PHC: Fix potential use-after-free in get_timestamp Move the phc->active check and resp pointer assignment to after acquiring the spinlock. Previously, phc->active was checked without holding the lock, and resp was cached from ena_dev->phc.virt_addr before the lock was acquired. If ena_com_phc_destroy() runs between the lockless active check and the lock acquisition, it sets active=false, releases the lock, frees the DMA memory, and sets virt_addr=NULL. The get_timestamp path would then read a NULL virt_addr and dereference it. With both the active check and the pointer read under the lock, destroy cannot free the memory while get_timestamp is using it. Fixes: e0ea34158ee8 ("net: ena: Add PHC support in the ENA driver") Cc: stable@vger.kernel.org Signed-off-by: Arthur Kiyanovski Reviewed-by: Vadim Fedorenko Link: https://patch.msgid.link/20260508062126.7273-1-akiyano@amazon.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c index e67b592e56976..8c86789d867a5 100644 --- a/drivers/net/ethernet/amazon/ena/ena_com.c +++ b/drivers/net/ethernet/amazon/ena/ena_com.c @@ -1782,20 +1782,23 @@ void ena_com_phc_destroy(struct ena_com_dev *ena_dev) int ena_com_phc_get_timestamp(struct ena_com_dev *ena_dev, u64 *timestamp) { - volatile struct ena_admin_phc_resp *resp = ena_dev->phc.virt_addr; const ktime_t zero_system_time = ktime_set(0, 0); struct ena_com_phc_info *phc = &ena_dev->phc; + volatile struct ena_admin_phc_resp *resp; ktime_t expire_time; ktime_t block_time; unsigned long flags = 0; int ret = 0; + spin_lock_irqsave(&phc->lock, flags); + if (!phc->active) { + spin_unlock_irqrestore(&phc->lock, flags); netdev_err(ena_dev->net_device, "PHC feature is not active in the device\n"); return -EOPNOTSUPP; } - spin_lock_irqsave(&phc->lock, flags); + resp = ena_dev->phc.virt_addr; /* Check if PHC is in blocked state */ if (unlikely(ktime_compare(phc->system_time, zero_system_time))) {