{"cve":"CVE-2024-56788","nvd":{"published":"2025-01-11T13:15:29.090","modified":"2026-08-04T11:22:27.453","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ethernet: oa_tc6: fix tx skb race condition between reference pointers\n\nThere are two skb pointers to manage tx skb's enqueued from n/w stack.\nwaiting_tx_skb pointer points to the tx skb which needs to be processed\nand ongoing_tx_skb pointer points to the tx skb which is being processed.\n\nSPI thread prepares the tx data chunks from the tx skb pointed by the\nongoing_tx_skb pointer. When the tx skb pointed by the ongoing_tx_skb is\nprocessed, the tx skb pointed by the waiting_tx_skb is assigned to\nongoing_tx_skb and the waiting_tx_skb pointer is assigned with NULL.\nWhenever there is a new tx skb from n/w stack, it will be assigned to\nwaiting_tx_skb pointer if it is NULL. Enqueuing and processing of a tx skb\nhandled in two different threads.\n\nConsider a scenario where the SPI thread processed an ongoing_tx_skb and\nit moves next tx skb from waiting_tx_skb pointer to ongoing_tx_skb pointer\nwithout doing any NULL check. At this time, if the waiting_tx_skb pointer\nis NULL then ongoing_tx_skb pointer is also assigned with NULL. After\nthat, if a new tx skb is assigned to waiting_tx_skb pointer by the n/w\nstack and there is a chance to overwrite the tx skb pointer with NULL in\nthe SPI thread. Finally one of the tx skb will be left as unhandled,\nresulting packet missing and memory leak.\n\n- Consider the below scenario where the TXC reported from the previous\ntransfer is 10 and ongoing_tx_skb holds an tx ethernet frame which can be\ntransported in 20 TXCs and waiting_tx_skb is still NULL.\n\ttx_credits = 10; /* 21 are filled in the previous transfer */\n\tongoing_tx_skb = 20;\n\twaiting_tx_skb = NULL; /* Still NULL */\n- So, (tc6->ongoing_tx_skb || tc6->waiting_tx_skb) becomes true.\n- After oa_tc6_prepare_spi_tx_buf_for_tx_skbs()\n\tongoing_tx_skb = 10;\n\twaiting_tx_skb = NULL; /* Still NULL */\n- Perform SPI transfer.\n- Process SPI rx buffer to get the TXC from footers.\n- Now let's assume previously filled 21 TXCs are freed so we are good to\ntransport the next remaining 10 tx chunks from ongoing_tx_skb.\n\ttx_credits = 21;\n\tongoing_tx_skb = 10;\n\twaiting_tx_skb = NULL;\n- So, (tc6->ongoing_tx_skb || tc6->waiting_tx_skb) becomes true again.\n- In the oa_tc6_prepare_spi_tx_buf_for_tx_skbs()\n\tongoing_tx_skb = NULL;\n\twaiting_tx_skb = NULL;\n\n- Now the below bad case might happen,\n\nThread1 (oa_tc6_start_xmit)\tThread2 (oa_tc6_spi_thread_handler)\n---------------------------\t-----------------------------------\n- if waiting_tx_skb is NULL\n\t\t\t\t- if ongoing_tx_skb is NULL\n\t\t\t\t- ongoing_tx_skb = waiting_tx_skb\n- waiting_tx_skb = skb\n\t\t\t\t- waiting_tx_skb = NULL\n\t\t\t\t...\n\t\t\t\t- ongoing_tx_skb = NULL\n- if waiting_tx_skb is NULL\n- waiting_tx_skb = skb\n\nTo overcome the above issue, protect the moving of tx skb reference from\nwaiting_tx_skb pointer to ongoing_tx_skb pointer and assigning new tx skb\nto waiting_tx_skb pointer, so that the other thread can't access the\nwaiting_tx_skb pointer until the current thread completes moving the tx\nskb reference safely.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","score":4.7},"cwes":["CWE-362"],"references":["https://git.kernel.org/stable/c/1f2eb6c32bae04b375bb7a0aedbeefb6dbbcb775","https://git.kernel.org/stable/c/e592b5110b3e9393881b0a019d86832bbf71a47f"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:58:20.756570362+00:00"},"epss":{"cve":"CVE-2024-56788","score":0.00245,"percentile":0.15738,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}