{"id":"AZL-53429","summary":"CVE-2024-50301 affecting package kernel for versions less than 6.6.64.2-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsecurity/keys: fix slab-out-of-bounds in key_task_permission\n\nKASAN reports an out of bounds read:\nBUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uidgid.h:36\nBUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.h:63 [inline]\nBUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x410\nsecurity/keys/permission.c:54\nRead of size 4 at addr ffff88813c3ab618 by task stress-ng/4362\n\nCPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafbffd6c3ede #15\nCall Trace:\n __dump_stack lib/dump_stack.c:82 [inline]\n dump_stack+0x107/0x167 lib/dump_stack.c:123\n print_address_description.constprop.0+0x19/0x170 mm/kasan/report.c:400\n __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560\n kasan_report+0x3a/0x50 mm/kasan/report.c:585\n __kuid_val include/linux/uidgid.h:36 [inline]\n uid_eq include/linux/uidgid.h:63 [inline]\n key_task_permission+0x394/0x410 security/keys/permission.c:54\n search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c:793\n\nThis issue was also reported by syzbot.\n\nIt can be reproduced by following these steps(more details [1]):\n1. Obtain more than 32 inputs that have similar hashes, which ends with the\n   pattern '0xxxxxxxe6'.\n2. Reboot and add the keys obtained in step 1.\n\nThe reproducer demonstrates how this issue happened:\n1. In the search_nested_keyrings function, when it iterates through the\n   slots in a node(below tag ascend_to_node), if the slot pointer is meta\n   and node-\u003eback_pointer != NULL(it means a root), it will proceed to\n   descend_to_node. However, there is an exception. If node is the root,\n   and one of the slots points to a shortcut, it will be treated as a\n   keyring.\n2. Whether the ptr is keyring decided by keyring_ptr_is_keyring function.\n   However, KEYRING_PTR_SUBTYPE is 0x2UL, the same as\n   ASSOC_ARRAY_PTR_SUBTYPE_MASK.\n3. When 32 keys with the similar hashes are added to the tree, the ROOT\n   has keys with hashes that are not similar (e.g. slot 0) and it splits\n   NODE A without using a shortcut. When NODE A is filled with keys that\n   all hashes are xxe6, the keys are similar, NODE A will split with a\n   shortcut. Finally, it forms the tree as shown below, where slot 6 points\n   to a shortcut.\n\n                      NODE A\n              +------\u003e+---+\n      ROOT    |       | 0 | xxe6\n      +---+   |       +---+\n xxxx | 0 | shortcut  :   : xxe6\n      +---+   |       +---+\n xxe6 :   :   |       |   | xxe6\n      +---+   |       +---+\n      | 6 |---+       :   : xxe6\n      +---+           +---+\n xxe6 :   :           | f | xxe6\n      +---+           +---+\n xxe6 | f |\n      +---+\n\n4. As mentioned above, If a slot(slot 6) of the root points to a shortcut,\n   it may be mistakenly transferred to a key*, leading to a read\n   out-of-bounds read.\n\nTo fix this issue, one should jump to descend_to_node if the ptr is a\nshortcut, regardless of whether the node is root or not.\n\n[1] https://lore.kernel.org/linux-kernel/1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com/\n\n[jarkko: tweaked the commit message a bit to have an appropriate closes\n tag.]","modified":"2026-04-01T05:18:03.152905Z","published":"2024-11-19T02:16:32Z","upstream":["CVE-2024-50301"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-50301"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.64.2-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-53429.json"}}],"schema_version":"1.7.5"}