| { |
| "containers": { |
| "cna": { |
| "providerMetadata": { |
| "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" |
| }, |
| "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": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04", |
| "lessThan": "4528c0c323085e645b8765913b4a7fd42cf49b65", |
| "status": "affected", |
| "versionType": "git" |
| }, |
| { |
| "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04", |
| "lessThan": "807fa14536b26803b858da878b643be72952a097", |
| "status": "affected", |
| "versionType": "git" |
| }, |
| { |
| "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04", |
| "lessThan": "a11ddb37bf367e6b5239b95ca759e5389bb46048", |
| "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": "semver" |
| }, |
| { |
| "version": "5.10.40", |
| "lessThanOrEqual": "5.10.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.12.7", |
| "lessThanOrEqual": "5.12.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.13", |
| "lessThanOrEqual": "*", |
| "status": "unaffected", |
| "versionType": "original_commit_for_fix" |
| } |
| ] |
| } |
| ], |
| "cpeApplicability": [ |
| { |
| "nodes": [ |
| { |
| "operator": "OR", |
| "negate": false, |
| "cpeMatch": [ |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.6", |
| "versionEndExcluding": "5.10.40" |
| }, |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.6", |
| "versionEndExcluding": "5.12.7" |
| }, |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.6", |
| "versionEndExcluding": "5.13" |
| } |
| ] |
| } |
| ] |
| } |
| ], |
| "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-1.2.0" |
| } |
| } |
| }, |
| "cveMetadata": { |
| "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", |
| "cveID": "CVE-2021-47069", |
| "requesterUserId": "gregkh@kernel.org", |
| "serial": "1", |
| "state": "PUBLISHED" |
| }, |
| "dataType": "CVE_RECORD", |
| "dataVersion": "5.0" |
| } |
