| 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-2024-26885: bpf: Fix DEVMAP_HASH overflow check on 32-bit arches |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: Fix DEVMAP_HASH overflow check on 32-bit arches |
| |
| The devmap code allocates a number hash buckets equal to the next power |
| of two of the max_entries value provided when creating the map. When |
| rounding up to the next power of two, the 32-bit variable storing the |
| number of buckets can overflow, and the code checks for overflow by |
| checking if the truncated 32-bit value is equal to 0. However, on 32-bit |
| arches the rounding up itself can overflow mid-way through, because it |
| ends up doing a left-shift of 32 bits on an unsigned long value. If the |
| size of an unsigned long is four bytes, this is undefined behaviour, so |
| there is no guarantee that we'll end up with a nice and tidy 0-value at |
| the end. |
| |
| Syzbot managed to turn this into a crash on arm32 by creating a |
| DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it. |
| Fix this by moving the overflow check to before the rounding up |
| operation. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26885 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 5.4.285 with commit 1f5e352b9088211fa5eb4e1639cd365f4f7d2f65 |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 5.10.227 with commit 4b81a9f92b3676cb74b907a7a209b3d15bd9a7f9 |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 5.15.153 with commit c826502bed93970f2fd488918a7b8d5f1d30e2e3 |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 6.1.83 with commit edf7990baa48de5097daa9ac02e06cb4c798a737 |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 6.6.23 with commit 250051acc21f9d4c5c595e4fcb55986ea08c4691 |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 6.7.11 with commit 22079b3a423382335f47d9ed32114e6c9fe88d7c |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 6.8.2 with commit e89386f62ce9a9ab9a94835a9890883c23d9d52c |
| Issue introduced in 5.4 with commit 6f9d451ab1a33728adb72d7ff66a7b374d665176 and fixed in 6.9 with commit 281d464a34f540de166cee74b723e97ac2515ec3 |
| |
| 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-2024-26885 |
| 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: |
| kernel/bpf/devmap.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/1f5e352b9088211fa5eb4e1639cd365f4f7d2f65 |
| https://git.kernel.org/stable/c/4b81a9f92b3676cb74b907a7a209b3d15bd9a7f9 |
| https://git.kernel.org/stable/c/c826502bed93970f2fd488918a7b8d5f1d30e2e3 |
| https://git.kernel.org/stable/c/edf7990baa48de5097daa9ac02e06cb4c798a737 |
| https://git.kernel.org/stable/c/250051acc21f9d4c5c595e4fcb55986ea08c4691 |
| https://git.kernel.org/stable/c/22079b3a423382335f47d9ed32114e6c9fe88d7c |
| https://git.kernel.org/stable/c/e89386f62ce9a9ab9a94835a9890883c23d9d52c |
| https://git.kernel.org/stable/c/281d464a34f540de166cee74b723e97ac2515ec3 |
