{ "dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": { "cveId": "CVE-2021-47069", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-29T22:33:44.296Z", "datePublished": "2024-03-01T21:15:08.598Z", "dateUpdated": "2024-08-04T05:24:39.653Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2024-05-29T05:01:35.389Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry\n\ndo_mq_timedreceive calls wq_sleep with a stack local address. The\nsender (do_mq_timedsend) uses this address to later call pipelined_send.\n\nThis leads to a very hard to trigger race where a do_mq_timedreceive\ncall might return and leave do_mq_timedsend to rely on an invalid\naddress, causing the following crash:\n\n RIP: 0010:wake_q_add_safe+0x13/0x60\n Call Trace:\n __x64_sys_mq_timedsend+0x2a9/0x490\n do_syscall_64+0x80/0x680\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\n RIP: 0033:0x7f5928e40343\n\nThe race occurs as:\n\n1. do_mq_timedreceive calls wq_sleep with the address of `struct\n ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it\n holds a valid `struct ext_wait_queue *` as long as the stack has not\n been overwritten.\n\n2. `ewq_addr` gets added to info->e_wait_q[RECV].list in wq_add, and\n do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call\n __pipelined_op.\n\n3. Sender calls __pipelined_op::smp_store_release(&this->state,\n STATE_READY). Here is where the race window begins. (`this` is\n `ewq_addr`.)\n\n4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it\n will see `state == STATE_READY` and break.\n\n5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed\n to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive's\n stack. (Although the address may not get overwritten until another\n function happens to touch it, which means it can persist around for an\n indefinite time.)\n\n6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a\n `struct ext_wait_queue *`, and uses it to find a task_struct to pass to\n the wake_q_add_safe call. In the lucky case where nothing has\n overwritten `ewq_addr` yet, `ewq_addr->task` is the right task_struct.\n In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a\n bogus address as the receiver's task_struct causing the crash.\n\ndo_mq_timedsend::__pipelined_op() should not dereference `this` after\nsetting STATE_READY, as the receiver counterpart is now free to return.\nChange __pipelined_op to call wake_q_add_safe on the receiver's\ntask_struct returned by get_task_struct, instead of dereferencing `this`\nwhich sits on the receiver's stack.\n\nAs Manfred pointed out, the race potentially also exists in\nipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare. Fix\nthose in the same way." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "ipc/mqueue.c", "ipc/msg.c", "ipc/sem.c" ], "versions": [ { "version": "0d97a82ba830", "lessThan": "4528c0c32308", "status": "affected", "versionType": "git" }, { "version": "0d97a82ba830", "lessThan": "807fa14536b2", "status": "affected", "versionType": "git" }, { "version": "0d97a82ba830", "lessThan": "a11ddb37bf36", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "ipc/mqueue.c", "ipc/msg.c", "ipc/sem.c" ], "versions": [ { "version": "5.6", "status": "affected" }, { "version": "0", "lessThan": "5.6", "status": "unaffected", "versionType": "custom" }, { "version": "5.10.40", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.12.7", "lessThanOrEqual": "5.12.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.13", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65" }, { "url": "https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097" }, { "url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048" } ], "title": "ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry", "x_generator": { "engine": "bippy-a5840b7849dd" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-06-21T16:15:09.996738Z", "id": "CVE-2021-47069", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-21T16:15:20.262Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:24:39.653Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048", "tags": [ "x_transferred" ] } ] } ] } }