high CVSS 7.1

CVE-2021-47346·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer() commit 6f755e85c332 ("coresight: Add helper for inserting synchronization packets") removed trailing '\0' from barrier_pkt array and updated the call sites like etb_update_buffer() to have proper checks for barrier_pkt size before read but missed updating tmc_update_etf_buffer() which still reads barrier_pkt past the array size resulting in KASAN out-of-bounds bug. Fix this by adding a check for barrier_pkt size before accessing like it is done in etb_update_buffer(). BUG: KASAN: global-out-of-bounds in tmc_update_etf_buffer+0x4b8/0x698 Read of size 4 at addr ffffffd05b7d1030 by task perf/2629 Call trace: dump_backtrace+0x0/0x27c show_stack+0x20/0x2c dump_stack+0x11c/0x188 print_address_description+0x3c/0x4a4 __kasan_report+0x140/0x164 kasan_report+0x10/0x18 __asan_report_load4_noabort+0x1c/0x24 tmc_update_etf_buffer+0x4b8/0x698 etm_event_stop+0x248/0x2d8 etm_event_del+0x20/0x2c event_sched_out+0x214/0x6f0 group_sched_out+0xd0/0x270 ctx_sched_out+0x2ec/0x518 __perf_event_task_sched_out+0x4fc/0xe6c __schedule+0x1094/0x16a0 preempt_schedule_irq+0x88/0x170 arm64_preempt_schedule_irq+0xf0/0x18c el1_irq+0xe8/0x180 perf_event_exec+0x4d8/0x56c setup_new_exec+0x204/0x400 load_elf_binary+0x72c/0x18c0 search_binary_handler+0x13c/0x420 load_script+0x500/0x6c4 search_binary_handler+0x13c/0x420 exec_binprm+0x118/0x654 __do_execve_file+0x77c/0xba4 __arm64_compat_sys_execve+0x98/0xac el0_svc_common+0x1f8/0x5e0 el0_svc_compat_handler+0x84/0xb0 el0_svc_compat+0x10/0x50 The buggy address belongs to the variable: barrier_pkt+0x10/0x40 Memory state around the buggy address: ffffffd05b7d0f00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00 ffffffd05b7d0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffffd05b7d1000: 00 00 00 00 00 00 fa fa fa fa fa fa 00 00 00 03 ^ ffffffd05b7d1080: fa fa fa fa 00 02 fa fa fa fa fa fa 03 fa fa fa ffffffd05b7d1100: fa fa fa fa 00 00 00 00 05 fa fa fa fa fa fa fa ==================================================================

Severity
high
Software
Kernel
Fixed in
5.13.3
Published
2024-05-21

Affected versions

From: 5.13

Until: 5.13.3

Fixed in: 5.13.3

How to fix this CVE

Update your Linux kernel to version 5.13.3 or later to patch a memory safety issue in the CoreSight trace buffer management subsystem. This vulnerability affects systems running kernel 5.13 through 5.13.2 and causes out-of-bounds memory reads during performance event tracing. Apply the kernel update immediately to prevent potential denial of service conditions.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your current kernel version with: uname -r
  2. Step 2: Verify if CoreSight tracing is enabled with: cat /sys/bus/event_source/devices/etm*/type (look for non-empty output)
  3. Step 3: Search kernel logs for KASAN out-of-bounds errors related to tmc_update_etf_buffer with: sudo journalctl -k | grep -i 'out-of-bounds\|tmc_update_etf_buffer'
  4. Step 4: After patching, confirm the new kernel is loaded with: uname -r and verify it reports version 5.13.3 or higher

FAQ

What is CVE-2021-47346?

This vulnerability is a global out-of-bounds memory read in the Linux kernel's CoreSight Embedded Trace Macrocell (ETF) buffer update function, triggered during performance event tracing operations on ARM-based systems.

Is CVE-2021-47346 being actively exploited?

No, this vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available. It primarily impacts system stability rather than security boundaries.

What versions of Kernel are affected by CVE-2021-47346?

Linux kernel versions 5.13 through 5.13.2 are vulnerable. The fix was included starting with kernel version 5.13.3.

How do I check if my server is vulnerable to CVE-2021-47346?

Run `uname -r` to check your kernel version—if it shows 5.13.0, 5.13.1, or 5.13.2, your system is vulnerable and requires patching.

Does Defensia detect CVE-2021-47346?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2021-47346 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2024-42256CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: cifs: Fix server re-repick on subrequest retry When a subrequest is marked for needing retry, netfs will call cifs_prepare_write() which will make cifs repick the server for the op before renegotiating credits; it then calls cifs_issue_write() which invokes smb2_async_writev() - which re-repicks the server. If a different server is then selected, this causes the increment of server->in_flight to happen against one record and the decrement to happen against another, leading to misaccounting. Fix this by just removing the repick code in smb2_async_writev(). As this is only called from netfslib-driven code, cifs_prepare_write() should always have been called first, and so server should never be NULL and the preparatory step is repeated in the event that we do a retry. The problem manifests as a warning looking something like: WARNING: CPU: 4 PID: 72896 at fs/smb/client/smb2ops.c:97 smb2_add_credits+0x3f0/0x9e0 [cifs] ... RIP: 0010:smb2_add_credits+0x3f0/0x9e0 [cifs] ... smb2_writev_callback+0x334/0x560 [cifs] cifs_demultiplex_thread+0x77a/0x11b0 [cifs] kthread+0x187/0x1d0 ret_from_fork+0x34/0x60 ret_from_fork_asm+0x1a/0x30 Which may be triggered by a number of different xfstests running against an Azure server in multichannel mode. generic/249 seems the most repeatable, but generic/215, generic/249 and generic/308 may also show it.
CVE-2024-38612CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix invalid unregister error path The error path of seg6_init() is wrong in case CONFIG_IPV6_SEG6_LWTUNNEL is not defined. In that case if seg6_hmac_init() fails, the genl_unregister_family() isn't called. This issue exist since commit 46738b1317e1 ("ipv6: sr: add option to control lwtunnel support"), and commit 5559cea2d5aa ("ipv6: sr: fix possible use-after-free and null-ptr-deref") replaced unregister_pernet_subsys() with genl_unregister_family() in this error path.
CVE-2024-39462CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: clk: bcm: dvp: Assign ->num before accessing ->hws Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") annotated the hws member of 'struct clk_hw_onecell_data' with __counted_by, which informs the bounds sanitizer about the number of elements in hws, so that it can warn when hws is accessed out of bounds. As noted in that change, the __counted_by member must be initialized with the number of elements before the first array access happens, otherwise there will be a warning from each access prior to the initialization because the number of elements is zero. This occurs in clk_dvp_probe() due to ->num being assigned after ->hws has been accessed: UBSAN: array-index-out-of-bounds in drivers/clk/bcm/clk-bcm2711-dvp.c:59:2 index 0 is out of range for type 'struct clk_hw *[] __counted_by(num)' (aka 'struct clk_hw *[]') Move the ->num initialization to before the first access of ->hws, which clears up the warning.
CVE-2024-38541CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: of: module: add buffer overflow check in of_modalias() In of_modalias(), if the buffer happens to be too small even for the 1st snprintf() call, the len parameter will become negative and str parameter (if not NULL initially) will point beyond the buffer's end. Add the buffer overflow check after the 1st snprintf() call and fix such check after the strlen() call (accounting for the terminating NUL char).
CVE-2021-47548CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge_srst_by_port() The if statement: if (port >= DSAF_GE_NUM) return; limits the value of port less than DSAF_GE_NUM (i.e., 8). However, if the value of port is 6 or 7, an array overflow could occur: port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off; because the length of dsaf_dev->mac_cb is DSAF_MAX_PORT_NUM (i.e., 6). To fix this possible array overflow, we first check port and if it is greater than or equal to DSAF_MAX_PORT_NUM, the function returns.

References

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