| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-26690: net: stmmac: protect updates of 64-bit statistics counters |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net: stmmac: protect updates of 64-bit statistics counters |
| |
| As explained by a comment in <linux/u64_stats_sync.h>, write side of struct |
| u64_stats_sync must ensure mutual exclusion, or one seqcount update could |
| be lost on 32-bit platforms, thus blocking readers forever. Such lockups |
| have been observed in real world after stmmac_xmit() on one CPU raced with |
| stmmac_napi_poll_tx() on another CPU. |
| |
| To fix the issue without introducing a new lock, split the statics into |
| three parts: |
| |
| 1. fields updated only under the tx queue lock, |
| 2. fields updated only during NAPI poll, |
| 3. fields updated only from interrupt context, |
| |
| Updates to fields in the first two groups are already serialized through |
| other locks. It is sufficient to split the existing struct u64_stats_sync |
| so that each group has its own. |
| |
| Note that tx_set_ic_bit is updated from both contexts. Split this counter |
| so that each context gets its own, and calculate their sum to get the total |
| value in stmmac_get_ethtool_stats(). |
| |
| For the third group, multiple interrupts may be processed by different CPUs |
| at the same time, but interrupts on the same CPU will not nest. Move fields |
| from this group to a newly created per-cpu struct stmmac_pcpu_stats. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26690 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.6 with commit 133466c3bbe171f826294161db203f7670bb30c8 and fixed in 6.6.18 with commit 9680b2ab54ba8d72581100e8c45471306101836e |
| Issue introduced in 6.6 with commit 133466c3bbe171f826294161db203f7670bb30c8 and fixed in 6.7.6 with commit e6af0f082a4b87b99ad033003be2a904a1791b3f |
| Issue introduced in 6.6 with commit 133466c3bbe171f826294161db203f7670bb30c8 and fixed in 6.8 with commit 38cc3c6dcc09dc3a1800b5ec22aef643ca11eab8 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-26690 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/net/ethernet/stmicro/stmmac/common.h |
| drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c |
| drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c |
| drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c |
| drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c |
| drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c |
| drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/9680b2ab54ba8d72581100e8c45471306101836e |
| https://git.kernel.org/stable/c/e6af0f082a4b87b99ad033003be2a904a1791b3f |
| https://git.kernel.org/stable/c/38cc3c6dcc09dc3a1800b5ec22aef643ca11eab8 |
