{"id":"CVE-2021-47346","state":"PUBLISHED","title":"coresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncoresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer()\n\ncommit 6f755e85c332 (\"coresight: Add helper for inserting synchronization\npackets\") removed trailing '\\0' from barrier_pkt array and updated the\ncall sites like etb_update_buffer() to have proper checks for barrier_pkt\nsize before read but missed updating tmc_update_etf_buffer() which still\nreads barrier_pkt past the array size resulting in KASAN out-of-bounds\nbug. Fix this by adding a check for barrier_pkt size before accessing\nlike it is done in etb_update_buffer().\n\n BUG: KASAN: global-out-of-bounds in tmc_update_etf_buffer+0x4b8/0x698\n Read of size 4 at addr ffffffd05b7d1030 by task perf/2629\n\n Call trace:\n  dump_backtrace+0x0/0x27c\n  show_stack+0x20/0x2c\n  dump_stack+0x11c/0x188\n  print_address_description+0x3c/0x4a4\n  __kasan_report+0x140/0x164\n  kasan_report+0x10/0x18\n  __asan_report_load4_noabort+0x1c/0x24\n  tmc_update_etf_buffer+0x4b8/0x698\n  etm_event_stop+0x248/0x2d8\n  etm_event_del+0x20/0x2c\n  event_sched_out+0x214/0x6f0\n  group_sched_out+0xd0/0x270\n  ctx_sched_out+0x2ec/0x518\n  __perf_event_task_sched_out+0x4fc/0xe6c\n  __schedule+0x1094/0x16a0\n  preempt_schedule_irq+0x88/0x170\n  arm64_preempt_schedule_irq+0xf0/0x18c\n  el1_irq+0xe8/0x180\n  perf_event_exec+0x4d8/0x56c\n  setup_new_exec+0x204/0x400\n  load_elf_binary+0x72c/0x18c0\n  search_binary_handler+0x13c/0x420\n  load_script+0x500/0x6c4\n  search_binary_handler+0x13c/0x420\n  exec_binprm+0x118/0x654\n  __do_execve_file+0x77c/0xba4\n  __arm64_compat_sys_execve+0x98/0xac\n  el0_svc_common+0x1f8/0x5e0\n  el0_svc_compat_handler+0x84/0xb0\n  el0_svc_compat+0x10/0x50\n\n The buggy address belongs to the variable:\n  barrier_pkt+0x10/0x40\n\n Memory state around the buggy address:\n  ffffffd05b7d0f00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00\n  ffffffd05b7d0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n >ffffffd05b7d1000: 00 00 00 00 00 00 fa fa fa fa fa fa 00 00 00 03\n                                      ^\n  ffffffd05b7d1080: fa fa fa fa 00 02 fa fa fa fa fa fa 03 fa fa fa\n  ffffffd05b7d1100: fa fa fa fa 00 00 00 00 05 fa fa fa fa fa fa fa\n ==================================================================","publishedAt":"2024-05-21T14:35:52.284Z","updatedAt":"2026-08-05T08:47:21.617Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"04bd77ef4f4d9fc6102023b85f4590fc2130aac5","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"ef0a06acc6b16388640ad367eedfa2a17f1945db","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"35c1c4bd2d59ad734129d4e232af9d1098023918","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"733d4d95c0101d5f277b8e4910411d016e49a9dc","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"0115687be7b13993066aef602253a53d55f5b11f","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"5fae8a946ac2df879caf3f79a193d4766d00239b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/coresight-tmc-etf.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.14","versionType":"semver"},{"version":"4.19.198","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.133","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.51","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.12.18","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13.3","status":"unaffected","lessThanOrEqual":"5.13.*","versionType":"semver"},{"version":"5.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/coresight-tmc-etf.c"]}],"references":["https://git.kernel.org/stable/c/04bd77ef4f4d9fc6102023b85f4590fc2130aac5","https://git.kernel.org/stable/c/ef0a06acc6b16388640ad367eedfa2a17f1945db","https://git.kernel.org/stable/c/35c1c4bd2d59ad734129d4e232af9d1098023918","https://git.kernel.org/stable/c/733d4d95c0101d5f277b8e4910411d016e49a9dc","https://git.kernel.org/stable/c/0115687be7b13993066aef602253a53d55f5b11f","https://git.kernel.org/stable/c/5fae8a946ac2df879caf3f79a193d4766d00239b"],"weaknesses":[],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47346.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47346","state":"PUBLISHED","datePublished":"2024-05-21T14:35:52.284Z","dateUpdated":"2026-08-05T08:47:21.617Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-05-21T14:28:16.980Z"},"containers":{"cna":{"title":"coresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncoresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer()\n\ncommit 6f755e85c332 (\"coresight: Add helper for inserting synchronization\npackets\") removed trailing '\\0' from barrier_pkt array and updated the\ncall sites like etb_update_buffer() to have proper checks for barrier_pkt\nsize before read but missed updating tmc_update_etf_buffer() which still\nreads barrier_pkt past the array size resulting in KASAN out-of-bounds\nbug. Fix this by adding a check for barrier_pkt size before accessing\nlike it is done in etb_update_buffer().\n\n BUG: KASAN: global-out-of-bounds in tmc_update_etf_buffer+0x4b8/0x698\n Read of size 4 at addr ffffffd05b7d1030 by task perf/2629\n\n Call trace:\n  dump_backtrace+0x0/0x27c\n  show_stack+0x20/0x2c\n  dump_stack+0x11c/0x188\n  print_address_description+0x3c/0x4a4\n  __kasan_report+0x140/0x164\n  kasan_report+0x10/0x18\n  __asan_report_load4_noabort+0x1c/0x24\n  tmc_update_etf_buffer+0x4b8/0x698\n  etm_event_stop+0x248/0x2d8\n  etm_event_del+0x20/0x2c\n  event_sched_out+0x214/0x6f0\n  group_sched_out+0xd0/0x270\n  ctx_sched_out+0x2ec/0x518\n  __perf_event_task_sched_out+0x4fc/0xe6c\n  __schedule+0x1094/0x16a0\n  preempt_schedule_irq+0x88/0x170\n  arm64_preempt_schedule_irq+0xf0/0x18c\n  el1_irq+0xe8/0x180\n  perf_event_exec+0x4d8/0x56c\n  setup_new_exec+0x204/0x400\n  load_elf_binary+0x72c/0x18c0\n  search_binary_handler+0x13c/0x420\n  load_script+0x500/0x6c4\n  search_binary_handler+0x13c/0x420\n  exec_binprm+0x118/0x654\n  __do_execve_file+0x77c/0xba4\n  __arm64_compat_sys_execve+0x98/0xac\n  el0_svc_common+0x1f8/0x5e0\n  el0_svc_compat_handler+0x84/0xb0\n  el0_svc_compat+0x10/0x50\n\n The buggy address belongs to the variable:\n  barrier_pkt+0x10/0x40\n\n Memory state around the buggy address:\n  ffffffd05b7d0f00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00\n  ffffffd05b7d0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n >ffffffd05b7d1000: 00 00 00 00 00 00 fa fa fa fa fa fa 00 00 00 03\n                                      ^\n  ffffffd05b7d1080: fa fa fa fa 00 02 fa fa fa fa fa fa 03 fa fa fa\n  ffffffd05b7d1100: fa fa fa fa 00 00 00 00 05 fa fa fa fa fa fa fa\n =================================================================="}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"04bd77ef4f4d9fc6102023b85f4590fc2130aac5","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"ef0a06acc6b16388640ad367eedfa2a17f1945db","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"35c1c4bd2d59ad734129d4e232af9d1098023918","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"733d4d95c0101d5f277b8e4910411d016e49a9dc","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"0115687be7b13993066aef602253a53d55f5b11f","versionType":"git"},{"version":"0c3fc4d5fa26092853278145aca9b21fa52a3e93","status":"affected","lessThan":"5fae8a946ac2df879caf3f79a193d4766d00239b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/coresight-tmc-etf.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.14","versionType":"semver"},{"version":"4.19.198","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.133","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.51","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.12.18","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13.3","status":"unaffected","lessThanOrEqual":"5.13.*","versionType":"semver"},{"version":"5.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/coresight-tmc-etf.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/04bd77ef4f4d9fc6102023b85f4590fc2130aac5"},{"url":"https://git.kernel.org/stable/c/ef0a06acc6b16388640ad367eedfa2a17f1945db"},{"url":"https://git.kernel.org/stable/c/35c1c4bd2d59ad734129d4e232af9d1098023918"},{"url":"https://git.kernel.org/stable/c/733d4d95c0101d5f277b8e4910411d016e49a9dc"},{"url":"https://git.kernel.org/stable/c/0115687be7b13993066aef602253a53d55f5b11f"},{"url":"https://git.kernel.org/stable/c/5fae8a946ac2df879caf3f79a193d4766d00239b"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through the CoreSight ETM perf PMU path (perf_event_open → etm_event_stop → tmc_update_etf_buffer), which requires local syscall access on a system with CoreSight ETF hardware.\nAC:L - An attacker who can open a cs_etm session can reliably force lost=true by using a small AUX buffer so to_read exceeds handle->size, which engages the broken barrier_pkt walk without depending on races or uncontrolled state.\nPR:L - Under the default perf_event_paranoid=2, an unprivileged user can open a per-task cs_etm event with exclude_kernel set; etm_event_init imposes no CAP_PERFMON/CAP_SYS_ADMIN check, so real root is not required.\nUI:N - The attacker configures and drives the perf session themselves; no separate victim action is required to reach tmc_update_etf_buffer.\nS:U - Impact stays within the host kernel authority (kernel memory disclosure / potential oops); there is no VM, IOMMU, or sandbox boundary crossing.\nC:H - When lost is set, the vulnerable loop keeps reading past coresight_barrier_pkt and writes those OOB kernel words into the attacker-readable perf AUX buffer, yielding an unbounded-until-zero out-of-bounds kernel read to userspace.\nI:N - The only stores are into the attacker’s own AUX data_pages; there is no out-of-bounds or attacker-controlled write to other kernel memory or integrity-sensitive state.\nA:H - The global out-of-bounds read is a memory-safety violation that can fault if the walk proceeds into unmapped memory, and per scoring policy the higher availability impact is selected when a crash cannot be ruled out."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T08:47:21.617Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"4.19.198"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.4.133"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.10.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.12.18"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.13.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.14"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2024-06-12T14:59:57.859823Z","id":"CVE-2021-47346","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-06-12T15:00:09.791Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/04bd77ef4f4d9fc6102023b85f4590fc2130aac5","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/ef0a06acc6b16388640ad367eedfa2a17f1945db","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/35c1c4bd2d59ad734129d4e232af9d1098023918","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/733d4d95c0101d5f277b8e4910411d016e49a9dc","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/0115687be7b13993066aef602253a53d55f5b11f","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/5fae8a946ac2df879caf3f79a193d4766d00239b","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-04T05:32:08.526Z"}}]}}}