| 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-2021-47333: misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge |
| |
| There is an issue with the ASPM(optional) capability checking function. |
| A device might be attached to root complex directly, in this case, |
| bus->self(bridge) will be NULL, thus priv->parent_pdev is NULL. |
| Since alcor_pci_init_check_aspm(priv->parent_pdev) checks the PCI link's |
| ASPM capability and populate parent_cap_off, which will be used later by |
| alcor_pci_aspm_ctrl() to dynamically turn on/off device, what we can do |
| here is to avoid checking the capability if we are on the root complex. |
| This will make pdev_cap_off 0 and alcor_pci_aspm_ctrl() will simply |
| return when bring called, effectively disable ASPM for the device. |
| |
| [ 1.246492] BUG: kernel NULL pointer dereference, address: 00000000000000c0 |
| [ 1.248731] RIP: 0010:pci_read_config_byte+0x5/0x40 |
| [ 1.253998] Call Trace: |
| [ 1.254131] ? alcor_pci_find_cap_offset.isra.0+0x3a/0x100 [alcor_pci] |
| [ 1.254476] alcor_pci_probe+0x169/0x2d5 [alcor_pci] |
| |
| The Linux kernel CVE team has assigned CVE-2021-47333 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.4.134 with commit d2639ffdcad463b358b6bef8645ff81715daffcb |
| Fixed in 5.10.52 with commit 58f69684ba03e5b0e0a3ae844a845280c0f06309 |
| Fixed in 5.12.19 with commit 717cf5ae52322ddbdf3ac2c584b34c5970b0d174 |
| Fixed in 5.13.4 with commit 09d154990ca82d14aed2b72796f6c8845e2e605d |
| Fixed in 5.14 with commit 3ce3e45cc333da707d4d6eb433574b990bcc26f5 |
| |
| 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-2021-47333 |
| 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/misc/cardreader/alcor_pci.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/d2639ffdcad463b358b6bef8645ff81715daffcb |
| https://git.kernel.org/stable/c/58f69684ba03e5b0e0a3ae844a845280c0f06309 |
| https://git.kernel.org/stable/c/717cf5ae52322ddbdf3ac2c584b34c5970b0d174 |
| https://git.kernel.org/stable/c/09d154990ca82d14aed2b72796f6c8845e2e605d |
| https://git.kernel.org/stable/c/3ce3e45cc333da707d4d6eb433574b990bcc26f5 |
