| 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-2024-35870: smb: client: fix UAF in smb2_reconnect_server() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| smb: client: fix UAF in smb2_reconnect_server() |
| |
| The UAF bug is due to smb2_reconnect_server() accessing a session that |
| is already being teared down by another thread that is executing |
| __cifs_put_smb_ses(). This can happen when (a) the client has |
| connection to the server but no session or (b) another thread ends up |
| setting @ses->ses_status again to something different than |
| SES_EXITING. |
| |
| To fix this, we need to make sure to unconditionally set |
| @ses->ses_status to SES_EXITING and prevent any other threads from |
| setting a new status while we're still tearing it down. |
| |
| The following can be reproduced by adding some delay to right after |
| the ipc is freed in __cifs_put_smb_ses() - which will give |
| smb2_reconnect_server() worker a chance to run and then accessing |
| @ses->ipc: |
| |
| kinit ... |
| mount.cifs //srv/share /mnt/1 -o sec=krb5,nohandlecache,echo_interval=10 |
| [disconnect srv] |
| ls /mnt/1 &>/dev/null |
| sleep 30 |
| kdestroy |
| [reconnect srv] |
| sleep 10 |
| umount /mnt/1 |
| ... |
| CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed |
| CIFS: VFS: \\srv Send error in SessSetup = -126 |
| CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed |
| CIFS: VFS: \\srv Send error in SessSetup = -126 |
| general protection fault, probably for non-canonical address |
| 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI |
| CPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc2 #1 |
| Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39 |
| 04/01/2014 |
| Workqueue: cifsiod smb2_reconnect_server [cifs] |
| RIP: 0010:__list_del_entry_valid_or_report+0x33/0xf0 |
| Code: 4f 08 48 85 d2 74 42 48 85 c9 74 59 48 b8 00 01 00 00 00 00 ad |
| de 48 39 c2 74 61 48 b8 22 01 00 00 00 00 74 69 <48> 8b 01 48 39 f8 75 |
| 7b 48 8b 72 08 48 39 c6 0f 85 88 00 00 00 b8 |
| RSP: 0018:ffffc900001bfd70 EFLAGS: 00010a83 |
| RAX: dead000000000122 RBX: ffff88810da53838 RCX: 6b6b6b6b6b6b6b6b |
| RDX: 6b6b6b6b6b6b6b6b RSI: ffffffffc02f6878 RDI: ffff88810da53800 |
| RBP: ffff88810da53800 R08: 0000000000000001 R09: 0000000000000000 |
| R10: 0000000000000000 R11: 0000000000000001 R12: ffff88810c064000 |
| R13: 0000000000000001 R14: ffff88810c064000 R15: ffff8881039cc000 |
| FS: 0000000000000000(0000) GS:ffff888157c00000(0000) |
| knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 00007fe3728b1000 CR3: 000000010caa4000 CR4: 0000000000750ef0 |
| PKRU: 55555554 |
| Call Trace: |
| <TASK> |
| ? die_addr+0x36/0x90 |
| ? exc_general_protection+0x1c1/0x3f0 |
| ? asm_exc_general_protection+0x26/0x30 |
| ? __list_del_entry_valid_or_report+0x33/0xf0 |
| __cifs_put_smb_ses+0x1ae/0x500 [cifs] |
| smb2_reconnect_server+0x4ed/0x710 [cifs] |
| process_one_work+0x205/0x6b0 |
| worker_thread+0x191/0x360 |
| ? __pfx_worker_thread+0x10/0x10 |
| kthread+0xe2/0x110 |
| ? __pfx_kthread+0x10/0x10 |
| ret_from_fork+0x34/0x50 |
| ? __pfx_kthread+0x10/0x10 |
| ret_from_fork_asm+0x1a/0x30 |
| </TASK> |
| |
| The Linux kernel CVE team has assigned CVE-2024-35870 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 6.1.121 with commit 755fe68cd4b59e1d2a2dd3286177fd4404f57fed |
| Fixed in 6.6.29 with commit 6202996a1c1887e83d0b3b0fcd86d0e5e6910ea0 |
| Fixed in 6.8.5 with commit 45f2beda1f1bc3d962ec07db1ccc3197c25499a5 |
| Fixed in 6.9 with commit 24a9799aa8efecd0eb55a75e35f9d8e6400063aa |
| |
| 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-2024-35870 |
| 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/smb/client/connect.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/755fe68cd4b59e1d2a2dd3286177fd4404f57fed |
| https://git.kernel.org/stable/c/6202996a1c1887e83d0b3b0fcd86d0e5e6910ea0 |
| https://git.kernel.org/stable/c/45f2beda1f1bc3d962ec07db1ccc3197c25499a5 |
| https://git.kernel.org/stable/c/24a9799aa8efecd0eb55a75e35f9d8e6400063aa |
