| 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-2021-47646: Revert "Revert "block, bfq: honor already-setup queue merges"" |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| Revert "Revert "block, bfq: honor already-setup queue merges"" |
| |
| A crash [1] happened to be triggered in conjunction with commit |
| 2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The |
| latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq: |
| honor already-setup queue merges""). Yet, the reverted commit was not |
| the one introducing the bug. In fact, it actually triggered a UAF |
| introduced by a different commit, and now fixed by commit d29bd41428cf |
| ("block, bfq: reset last_bfqq_created on group change"). |
| |
| So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq: |
| honor already-setup queue merges") out. This commit restores it. |
| |
| [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503 |
| |
| The Linux kernel CVE team has assigned CVE-2021-47646 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.12 with commit aee69d78dec0ffdf82e35d57c626e80dddc314d5 and fixed in 4.19.238 with commit f990f0985eda59d4f29fc83fcf300c92b1225d39 |
| Issue introduced in 4.12 with commit aee69d78dec0ffdf82e35d57c626e80dddc314d5 and fixed in 5.4.189 with commit 931aff627469a75c77b9fd3823146d0575afffd6 |
| Issue introduced in 4.12 with commit aee69d78dec0ffdf82e35d57c626e80dddc314d5 and fixed in 5.10.110 with commit cc051f497eac9d8a0d816cd4bffa3415f2724871 |
| Issue introduced in 4.12 with commit aee69d78dec0ffdf82e35d57c626e80dddc314d5 and fixed in 5.15.33 with commit 65d8a737452e88f251fe5d925371de6d606df613 |
| Issue introduced in 4.12 with commit aee69d78dec0ffdf82e35d57c626e80dddc314d5 and fixed in 5.16.19 with commit abc2129e646af7b43025d90a071f83043f1ae76c |
| Issue introduced in 4.12 with commit aee69d78dec0ffdf82e35d57c626e80dddc314d5 and fixed in 5.17.2 with commit 4083925bd6dc89216d156474a8076feec904e607 |
| Issue introduced in 4.12 with commit aee69d78dec0ffdf82e35d57c626e80dddc314d5 and fixed in 5.18 with commit 15729ff8143f8135b03988a100a19e66d7cb7ecd |
| |
| 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-2021-47646 |
| 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: |
| block/bfq-iosched.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/f990f0985eda59d4f29fc83fcf300c92b1225d39 |
| https://git.kernel.org/stable/c/931aff627469a75c77b9fd3823146d0575afffd6 |
| https://git.kernel.org/stable/c/cc051f497eac9d8a0d816cd4bffa3415f2724871 |
| https://git.kernel.org/stable/c/65d8a737452e88f251fe5d925371de6d606df613 |
| https://git.kernel.org/stable/c/abc2129e646af7b43025d90a071f83043f1ae76c |
| https://git.kernel.org/stable/c/4083925bd6dc89216d156474a8076feec904e607 |
| https://git.kernel.org/stable/c/15729ff8143f8135b03988a100a19e66d7cb7ecd |
