| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-37984: crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP() |
| |
| Herbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa |
| implementation's ->key_size() callback returns an unusually large value. |
| Herbert instead suggests (for a division by 8): |
| |
| X / 8 + !!(X & 7) |
| |
| Based on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and |
| use it in lieu of DIV_ROUND_UP() for ->key_size() return values. |
| |
| Additionally, use the macro in ecc_digits_from_bytes(), whose "nbytes" |
| parameter is a ->key_size() return value in some instances, or a |
| user-specified ASN.1 length in the case of ecdsa_get_signature_rs(). |
| |
| The Linux kernel CVE team has assigned CVE-2025-37984 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 6.14.5 with commit 921b8167f10708e38080f84e195cdc68a7a561f1 |
| Fixed in 6.15 with commit b16510a530d1e6ab9683f04f8fb34f2e0f538275 |
| |
| 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-2025-37984 |
| 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: |
| crypto/ecc.c |
| crypto/ecdsa-p1363.c |
| crypto/ecdsa-x962.c |
| include/linux/math.h |
| |
| |
| 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/921b8167f10708e38080f84e195cdc68a7a561f1 |
| https://git.kernel.org/stable/c/b16510a530d1e6ab9683f04f8fb34f2e0f538275 |
