| 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-2021-47218: selinux: fix NULL-pointer dereference when hashtab allocation fails |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| selinux: fix NULL-pointer dereference when hashtab allocation fails |
| |
| When the hash table slot array allocation fails in hashtab_init(), |
| h->size is left initialized with a non-zero value, but the h->htable |
| pointer is NULL. This may then cause a NULL pointer dereference, since |
| the policydb code relies on the assumption that even after a failed |
| hashtab_init(), hashtab_map() and hashtab_destroy() can be safely called |
| on it. Yet, these detect an empty hashtab only by looking at the size. |
| |
| Fix this by making sure that hashtab_init() always leaves behind a valid |
| empty hashtab when the allocation fails. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47218 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.8 with commit 03414a49ad5f3c56988c36d2070e402ffa17feaf and fixed in 5.10.82 with commit b17dd53cac769dd13031b0ca34f90cc65e523fab |
| Issue introduced in 5.8 with commit 03414a49ad5f3c56988c36d2070e402ffa17feaf and fixed in 5.15.5 with commit 83c8ab8503adf56bf68dafc7a382f4946c87da79 |
| Issue introduced in 5.8 with commit 03414a49ad5f3c56988c36d2070e402ffa17feaf and fixed in 5.16 with commit dc27f3c5d10c58069672215787a96b4fae01818b |
| |
| 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-2021-47218 |
| 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: |
| security/selinux/ss/hashtab.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/b17dd53cac769dd13031b0ca34f90cc65e523fab |
| https://git.kernel.org/stable/c/83c8ab8503adf56bf68dafc7a382f4946c87da79 |
| https://git.kernel.org/stable/c/dc27f3c5d10c58069672215787a96b4fae01818b |
