| From bippy-1.1.0 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-2023-53083: nfsd: don't replace page in rq_pages if it's a continuation of last page |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| nfsd: don't replace page in rq_pages if it's a continuation of last page |
| |
| The splice read calls nfsd_splice_actor to put the pages containing file |
| data into the svc_rqst->rq_pages array. It's possible however to get a |
| splice result that only has a partial page at the end, if (e.g.) the |
| filesystem hands back a short read that doesn't cover the whole page. |
| |
| nfsd_splice_actor will plop the partial page into its rq_pages array and |
| return. Then later, when nfsd_splice_actor is called again, the |
| remainder of the page may end up being filled out. At this point, |
| nfsd_splice_actor will put the page into the array _again_ corrupting |
| the reply. If this is done enough times, rq_next_page will overrun the |
| array and corrupt the trailing fields -- the rq_respages and |
| rq_next_page pointers themselves. |
| |
| If we've already added the page to the array in the last pass, don't add |
| it to the array a second time when dealing with a splice continuation. |
| This was originally handled properly in nfsd_splice_actor, but commit |
| 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") removed the check |
| for it. |
| |
| The Linux kernel CVE team has assigned CVE-2023-53083 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.19 with commit 91e23b1c39820bfed642119ff6b6ef9f43cf09ce and fixed in 6.1.22 with commit 51ddb84baff6f09ad62b5999ece3ec172e4e3568 |
| Issue introduced in 5.19 with commit 91e23b1c39820bfed642119ff6b6ef9f43cf09ce and fixed in 6.2.9 with commit 0101067f376eb7b9afd00279270f25d5111a091d |
| Issue introduced in 5.19 with commit 91e23b1c39820bfed642119ff6b6ef9f43cf09ce and fixed in 6.3 with commit 27c934dd8832dd40fd34776f916dc201e18b319b |
| |
| 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-2023-53083 |
| 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: |
| fs/nfsd/vfs.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/8235cd619db6e67f1d7d26c55f1f3e4e575c947d |
| https://git.kernel.org/stable/c/12eca509234acb6b666802edf77408bb70d7bfca |
| https://git.kernel.org/stable/c/51ddb84baff6f09ad62b5999ece3ec172e4e3568 |
| https://git.kernel.org/stable/c/0101067f376eb7b9afd00279270f25d5111a091d |
| https://git.kernel.org/stable/c/27c934dd8832dd40fd34776f916dc201e18b319b |
