| 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-2024-50271: signal: restore the override_rlimit logic |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| signal: restore the override_rlimit logic |
| |
| Prior to commit d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of |
| ucounts") UCOUNT_RLIMIT_SIGPENDING rlimit was not enforced for a class of |
| signals. However now it's enforced unconditionally, even if |
| override_rlimit is set. This behavior change caused production issues. |
| |
| For example, if the limit is reached and a process receives a SIGSEGV |
| signal, sigqueue_alloc fails to allocate the necessary resources for the |
| signal delivery, preventing the signal from being delivered with siginfo. |
| This prevents the process from correctly identifying the fault address and |
| handling the error. From the user-space perspective, applications are |
| unaware that the limit has been reached and that the siginfo is |
| effectively 'corrupted'. This can lead to unpredictable behavior and |
| crashes, as we observed with java applications. |
| |
| Fix this by passing override_rlimit into inc_rlimit_get_ucounts() and skip |
| the comparison to max there if override_rlimit is set. This effectively |
| restores the old behavior. |
| |
| The Linux kernel CVE team has assigned CVE-2024-50271 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.14 with commit d64696905554e919321e31afc210606653b8f6a4 and fixed in 6.1.117 with commit 012f4d5d25e9ef92ee129bd5aa7aa60f692681e1 |
| Issue introduced in 5.14 with commit d64696905554e919321e31afc210606653b8f6a4 and fixed in 6.6.61 with commit 4877d9b2a2ebad3ae240127aaa4cb8258b145cf7 |
| Issue introduced in 5.14 with commit d64696905554e919321e31afc210606653b8f6a4 and fixed in 6.11.8 with commit 0208ea17a1e4456fbfe555f13ae5c28f3d671e40 |
| Issue introduced in 5.14 with commit d64696905554e919321e31afc210606653b8f6a4 and fixed in 6.12 with commit 9e05e5c7ee8758141d2db7e8fea2cab34500c6ed |
| |
| 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-2024-50271 |
| 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: |
| include/linux/user_namespace.h |
| kernel/signal.c |
| kernel/ucount.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/012f4d5d25e9ef92ee129bd5aa7aa60f692681e1 |
| https://git.kernel.org/stable/c/4877d9b2a2ebad3ae240127aaa4cb8258b145cf7 |
| https://git.kernel.org/stable/c/0208ea17a1e4456fbfe555f13ae5c28f3d671e40 |
| https://git.kernel.org/stable/c/9e05e5c7ee8758141d2db7e8fea2cab34500c6ed |
