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>
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade kernel-abi-stablelistsUpgrade kernel-64k-devel-matchedUpgrade kernel-coreUpgrade rvUpgrade kernel-zfcpdump-develUpgrade kernel-zfcpdump-modules-coreUpgrade kernelUpgrade kernel-rt-modules-coreUpgrade kernel-tools-libsUpgrade kernel-64k-develUpgrade kernel-toolsUpgrade kernel-modules-extraUpgrade kernel-rt-modulesUpgrade kernel-64k-modulesUpgrade kernel-64k-debug-modules-extraUpgrade kernel-64k-debug-devel-matchedUpgrade kernel-modules-coreUpgrade kernel-debug-modulesUpgrade kernel-zfcpdump-modulesUpgrade kernel-headersUpgrade kernel-64k-debugUpgrade kernel-zfcpdumpUpgrade kernel-64k-debug-coreUpgrade kernel-zfcpdump-coreUpgrade kernel-rt-debug-develUpgrade kernel-rt-debug-coreUpgrade kernel-rt-modules-extraUpgrade kernel-modulesUpgrade kernel-debug-modules-extraUpgrade kernel-64kUpgrade kernel-cross-headersUpgrade kernel-64k-coreUpgrade kernel-rt-debug-modulesUpgrade bpftoolUpgrade kernel-debug-modules-coreUpgrade kernel-rtUpgrade kernel-debug-devel-matchedUpgrade kernel-rt-develUpgrade kernel-rt-debug-modules-coreUpgrade kernel-64k-debug-modules-coreUpgrade kernel-uki-virtUpgrade kernel-tools-libs-develUpgrade kernel-64k-debug-modulesUpgrade kernel-zfcpdump-devel-matchedUpgrade libperfUpgrade kernel-docUpgrade kernel-rt-debug-modules-extraUpgrade python3-perfUpgrade kernel-develUpgrade kernel-devel-matchedUpgrade perfUpgrade rtlaUpgrade kernel-64k-debug-develUpgrade kernel-zfcpdump-modules-extraUpgrade kernel-debug-coreUpgrade kernel-rt-debugUpgrade kernel-64k-modules-coreUpgrade kernel-debug-uki-virtUpgrade kernel-rt-coreUpgrade kernel-64k-modules-extraUpgrade kernel-debugUpgrade kernel-debug-devel | Nov 4, 2024 | May 19, 2024 |
| Amazon Linux Ami 2 | — | Upgrade bpftoolUpgrade kernelUpgrade kernel-livepatch-5.10.235-227.919Upgrade perfUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-develUpgrade kernel-tools-develUpgrade kernel-debuginfoUpgrade kernel-livepatch-4.14.355-275.603Upgrade kernel-tools-debuginfoUpgrade perf-debuginfoUpgrade kernel-livepatch-5.15.178-120.187Upgrade kernel-headersUpgrade kernel-livepatch-5.10.234-225.921Upgrade kernel-debuginfo-common-x86_64Upgrade kernel-livepatch-5.10.236-228.935Upgrade python-perfUpgrade python-perf-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-tools | Mar 14, 2025 | May 19, 2024 |
| Amazon_linux_2023 | — | Upgrade python3-perfUpgrade kernel-libbpf-develUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-livepatch-6.1.112-122.189Upgrade kernel-debuginfo-common-aarch64Upgrade kernel-toolsUpgrade kernel-libbpf-staticUpgrade python3-perf-debuginfoUpgrade kernel-develUpgrade kernel-tools-develUpgrade kernel-modules-extra-commonUpgrade bpftoolUpgrade kernelUpgrade kernel-modules-extraUpgrade kernel-debuginfoUpgrade bpftool-debuginfoUpgrade perf-debuginfoUpgrade kernel-tools-debuginfoUpgrade kernel-headersUpgrade perfUpgrade kernel-libbpf | Feb 17, 2025 | May 19, 2024 |
| Debian | — | Upgrade linux-6.1Upgrade linux | Jan 13, 2025 | May 19, 2024 |
| Huawei Euleros 2_0_sp11 | — | Upgrade bpftoolUpgrade kernelUpgrade python3-perfUpgrade kernel-abi-stablelistsUpgrade kernel-tools-libsUpgrade kernel-tools | Oct 8, 2024 | May 19, 2024 |
| Huawei Euleros 2_0_sp12 | — | Upgrade python3-perfUpgrade kernel-tools-libsUpgrade bpftoolUpgrade kernel-toolsUpgrade kernelUpgrade kernel-abi-stablelists | Oct 9, 2024 | May 19, 2024 |
| Oracle_linux | — | Upgrade kernel | Jul 9, 2024 | May 19, 2024 |
| Redhat_linux | — | Upgrade kernel-rtNo solution existsUpgrade kernel | Jun 27, 2024 | May 19, 2024 |
| Rocky_linux | — | Upgrade perf-debuginfoUpgrade kernel-devel-matchedUpgrade rvUpgrade kernel-zfcpdump-develUpgrade libperf-debuginfoUpgrade kernel-rt-coreUpgrade kernel-rt-debug-kvmUpgrade kernel-headersUpgrade kernel-rtUpgrade kernel-toolsUpgrade perfUpgrade kernel-tools-libs-develUpgrade libperfUpgrade kernel-rt-debug-modules-extraUpgrade kernel-rt-debuginfoUpgrade kernel-rt-modulesUpgrade kernel-zfcpdump-modules-coreUpgrade kernel-debug-devel-matchedUpgrade python3-perfUpgrade kernel-debug-develUpgrade kernel-zfcpdump-debuginfoUpgrade kernel-modulesUpgrade kernel-modules-coreUpgrade kernel-uki-virtUpgrade kernel-develUpgrade kernel-rt-debug-develUpgrade kernel-rt-debug-modules-coreUpgrade rtlaUpgrade kernel-rt-debugUpgrade kernel-tools-libsUpgrade kernel-cross-headersUpgrade kernel-rt-debug-coreUpgrade kernel-coreUpgrade kernel-debug-coreUpgrade kernel-debuginfoUpgrade kernel-rt-develUpgrade kernel-rt-modules-coreUpgrade kernel-zfcpdumpUpgrade kernel-debug-modules-coreUpgrade kernel-rt-kvmUpgrade kernel-rt-debug-modulesUpgrade kernel-debug-modules-extraUpgrade python3-perf-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-rt-modules-extraUpgrade kernel-debugUpgrade kernel-modules-extraUpgrade kernel-rt-debug-debuginfoUpgrade kernel-debug-modulesUpgrade kernel-zfcpdump-modules-extraUpgrade kernel-zfcpdump-modulesUpgrade kernel-tools-debuginfoUpgrade kernel-zfcpdump-devel-matchedUpgrade kernel-zfcpdump-coreUpgrade kernel-debug-uki-virtUpgrade kernelUpgrade bpftoolUpgrade kernel-debug-debuginfo | Jul 16, 2024 | May 19, 2024 |
| Suse | — | Upgrade dtb-lgUpgrade kernel-rt-vdsoUpgrade kernel-kvmsmallUpgrade kselftests-kmp-azureUpgrade kselftests-kmp-defaultUpgrade cluster-md-kmp-defaultUpgrade kernel-default-extraUpgrade reiserfs-kmp-azureUpgrade kernel-sourceUpgrade kernel-azure-livepatch-develUpgrade kernel-syms-rtUpgrade kernel-azure-vdsoUpgrade kernel-zfcpdumpUpgrade kernel-debug-livepatch-develUpgrade kernel-default-livepatchUpgrade kernel-docs-htmlUpgrade kernel-obs-qaUpgrade kernel-source-azureUpgrade kernel-rt_debug-vdsoUpgrade kernel-kvmsmall-vdsoUpgrade kernel-rt-extraUpgrade kernel-rt-optionalUpgrade kernel-source-rtUpgrade kernel-default-base-rebuildUpgrade kernel-devel-azureUpgrade kernel-azure-develUpgrade ocfs2-kmp-rtUpgrade kernel-obs-buildUpgrade dtb-broadcomUpgrade kernel-kvmsmall-develUpgrade gfs2-kmp-rtUpgrade kernel-default-manUpgrade kernel-rtUpgrade dtb-qcomUpgrade dlm-kmp-64kbUpgrade dtb-rockchipUpgrade ocfs2-kmp-64kbUpgrade dtb-marvellUpgrade dtb-exynosUpgrade cluster-md-kmp-azureUpgrade kselftests-kmp-64kbUpgrade kernel-macrosUpgrade kernel-rt-livepatch-develUpgrade kernel-azure-baseUpgrade reiserfs-kmp-64kbUpgrade dlm-kmp-azureUpgrade kernel-rt_debugUpgrade dtb-apmUpgrade dtb-amlogicUpgrade kernel-syms-azureUpgrade dtb-armUpgrade gfs2-kmp-azureUpgrade dtb-sprdUpgrade dtb-alteraUpgrade ocfs2-kmp-defaultUpgrade kernel-rt-livepatchUpgrade kernel-docsUpgrade kernel-default-livepatch-develUpgrade kernel-64kb-develUpgrade kernel-64kbUpgrade reiserfs-kmp-rtUpgrade kernel-rt-develUpgrade kernel-default-vdsoUpgrade dtb-socionextUpgrade dtb-mediatekUpgrade kernel-64kb-livepatch-develUpgrade kernel-azure-extraUpgrade kernel-symsUpgrade kernel-defaultUpgrade cluster-md-kmp-64kbUpgrade dtb-renesasUpgrade kernel-default-optionalUpgrade kernel-64kb-optionalUpgrade dtb-freescaleUpgrade dtb-appleUpgrade cluster-md-kmp-rtUpgrade kernel-azureUpgrade kernel-devel-rtUpgrade kernel-default-baseUpgrade gfs2-kmp-defaultUpgrade dtb-xilinxUpgrade dlm-kmp-rtUpgrade dtb-amdUpgrade kernel-develUpgrade dtb-amazonUpgrade dtb-caviumUpgrade gfs2-kmp-64kbUpgrade dtb-allwinnerUpgrade kernel-debugUpgrade kernel-debug-develUpgrade kernel-debug-vdsoUpgrade kernel-64kb-extraUpgrade ocfs2-kmp-azureUpgrade kselftests-kmp-rtUpgrade kernel-source-vanillaUpgrade kernel-rt_debug-livepatch-develUpgrade kernel-kvmsmall-livepatch-develUpgrade kernel-default-develUpgrade kernel-azure-optionalUpgrade dtb-hisiliconUpgrade dlm-kmp-defaultUpgrade reiserfs-kmp-defaultUpgrade kernel-rt_debug-develUpgrade dtb-nvidia | Jun 13, 2024 | May 19, 2024 |
| Ubuntu | — | Upgrade linux-image-virtual-hwe-24.04Upgrade linux-image-gkeUpgrade linux-image-6.8.0-38-genericUpgrade linux-image-nvidiaUpgrade linux-image-ibm-lts-24.04Upgrade linux-image-kvmUpgrade linux-image-gcpUpgrade linux-image-generic-64kUpgrade linux-image-generic-hwe-24.04Upgrade linux-image-ibm-classicUpgrade linux-image-nvidia-64kUpgrade linux-image-genericUpgrade linux-image-oracle-64kUpgrade linux-image-6.8.0-1007-intelUpgrade linux-image-intelUpgrade linux-image-6.8.0-1006-gkeUpgrade linux-image-oem-24.04aUpgrade linux-image-oem-24.04Upgrade linux-image-virtualUpgrade linux-image-6.8.0-1009-nvidia-64kUpgrade linux-image-ibmUpgrade linux-image-6.8.0-1008-ibmUpgrade linux-image-6.8.0-1008-oracleUpgrade linux-image-6.8.0-1010-azureUpgrade linux-image-6.8.0-1008-oracle-64kUpgrade linux-image-azure-fdeUpgrade linux-image-raspiUpgrade linux-image-generic-lpaeUpgrade linux-image-6.8.0-38-lowlatency-64kUpgrade linux-image-6.8.0-1008-oemUpgrade linux-image-6.8.0-38-lowlatencyUpgrade linux-image-6.8.0-1009-nvidiaUpgrade linux-image-lowlatency-64kUpgrade linux-image-awsUpgrade linux-image-6.8.0-38-generic-64kUpgrade linux-image-generic-64k-hwe-24.04Upgrade linux-image-6.8.0-1007-raspiUpgrade linux-image-6.8.0-1011-awsUpgrade linux-image-6.8.0-1010-azure-fdeUpgrade linux-image-oracleUpgrade linux-image-6.8.0-1010-gcpUpgrade linux-image-azureUpgrade linux-image-lowlatency | Jul 12, 2024 | May 19, 2024 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Sep 22, 2025 | May 19, 2024 |
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