In the Linux kernel, the following vulnerability has been resolved:
security/keys: fix slab-out-of-bounds in key_task_permission
KASAN reports an out of bounds read:
BUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uidgid.h:36
BUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.h:63 [inline]
BUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x410
security/keys/permission.c:54
Read of size 4 at addr ffff88813c3ab618 by task stress-ng/4362
CPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafbffd6c3ede #15
Call Trace:
__dump_stack lib/dump_stack.c:82 [inline]
dump_stack+0x107/0x167 lib/dump_stack.c:123
print_address_description.constprop.0+0x19/0x170 mm/kasan/report.c:400
__kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560
kasan_report+0x3a/0x50 mm/kasan/report.c:585
__kuid_val include/linux/uidgid.h:36 [inline]
uid_eq include/linux/uidgid.h:63 [inline]
key_task_permission+0x394/0x410 security/keys/permission.c:54
search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c:793
This issue was also reported by syzbot.
It can be reproduced by following these steps(more details [1]):
1. Obtain more than 32 inputs that have similar hashes, which ends with the
pattern '0xxxxxxxe6'.
2. Reboot and add the keys obtained in step 1.
The reproducer demonstrates how this issue happened:
1. In the search_nested_keyrings function, when it iterates through the
slots in a node(below tag ascend_to_node), if the slot pointer is meta
and node->back_pointer != NULL(it means a root), it will proceed to
descend_to_node. However, there is an exception. If node is the root,
and one of the slots points to a shortcut, it will be treated as a
keyring.
2. Whether the ptr is keyring decided by keyring_ptr_is_keyring function.
However, KEYRING_PTR_SUBTYPE is 0x2UL, the same as
ASSOC_ARRAY_PTR_SUBTYPE_MASK.
3. When 32 keys with the similar hashes are added to the tree, the ROOT
has keys with hashes that are not similar (e.g. slot 0) and it splits
NODE A without using a shortcut. When NODE A is filled with keys that
all hashes are xxe6, the keys are similar, NODE A will split with a
shortcut. Finally, it forms the tree as shown below, where slot 6 points
to a shortcut.
NODE A
+------>+---+
ROOT | | 0 | xxe6
+---+ | +---+
xxxx | 0 | shortcut : : xxe6
+---+ | +---+
xxe6 : : | | | xxe6
+---+ | +---+
| 6 |---+ : : xxe6
+---+ +---+
xxe6 : : | f | xxe6
+---+ +---+
xxe6 | f |
+---+
4. As mentioned above, If a slot(slot 6) of the root points to a shortcut,
it may be mistakenly transferred to a key*, leading to a read
out-of-bounds read.
To fix this issue, one should jump to descend_to_node if the ptr is a
shortcut, regardless of whether the node is root or not.
[1] https://lore.kernel.org/linux-kernel/1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com/
[jarkko: tweaked the commit message a bit to have an appropriate closes
tag.]
Metrics
Affected Vendors & Products
References
History
Fri, 22 Nov 2024 14:00:00 +0000
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References |
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Metrics |
threat_severity
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threat_severity
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Fri, 22 Nov 2024 12:00:00 +0000
Type | Values Removed | Values Added |
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First Time appeared |
Linux
Linux linux Kernel |
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Weaknesses | CWE-125 | |
CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc6:*:*:*:*:*:* |
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Vendors & Products |
Linux
Linux linux Kernel |
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Metrics |
cvssV3_1
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Tue, 19 Nov 2024 01:45:00 +0000
Type | Values Removed | Values Added |
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Description | In the Linux kernel, the following vulnerability has been resolved: security/keys: fix slab-out-of-bounds in key_task_permission KASAN reports an out of bounds read: BUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uidgid.h:36 BUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.h:63 [inline] BUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x410 security/keys/permission.c:54 Read of size 4 at addr ffff88813c3ab618 by task stress-ng/4362 CPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafbffd6c3ede #15 Call Trace: __dump_stack lib/dump_stack.c:82 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:123 print_address_description.constprop.0+0x19/0x170 mm/kasan/report.c:400 __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560 kasan_report+0x3a/0x50 mm/kasan/report.c:585 __kuid_val include/linux/uidgid.h:36 [inline] uid_eq include/linux/uidgid.h:63 [inline] key_task_permission+0x394/0x410 security/keys/permission.c:54 search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c:793 This issue was also reported by syzbot. It can be reproduced by following these steps(more details [1]): 1. Obtain more than 32 inputs that have similar hashes, which ends with the pattern '0xxxxxxxe6'. 2. Reboot and add the keys obtained in step 1. The reproducer demonstrates how this issue happened: 1. In the search_nested_keyrings function, when it iterates through the slots in a node(below tag ascend_to_node), if the slot pointer is meta and node->back_pointer != NULL(it means a root), it will proceed to descend_to_node. However, there is an exception. If node is the root, and one of the slots points to a shortcut, it will be treated as a keyring. 2. Whether the ptr is keyring decided by keyring_ptr_is_keyring function. However, KEYRING_PTR_SUBTYPE is 0x2UL, the same as ASSOC_ARRAY_PTR_SUBTYPE_MASK. 3. When 32 keys with the similar hashes are added to the tree, the ROOT has keys with hashes that are not similar (e.g. slot 0) and it splits NODE A without using a shortcut. When NODE A is filled with keys that all hashes are xxe6, the keys are similar, NODE A will split with a shortcut. Finally, it forms the tree as shown below, where slot 6 points to a shortcut. NODE A +------>+---+ ROOT | | 0 | xxe6 +---+ | +---+ xxxx | 0 | shortcut : : xxe6 +---+ | +---+ xxe6 : : | | | xxe6 +---+ | +---+ | 6 |---+ : : xxe6 +---+ +---+ xxe6 : : | f | xxe6 +---+ +---+ xxe6 | f | +---+ 4. As mentioned above, If a slot(slot 6) of the root points to a shortcut, it may be mistakenly transferred to a key*, leading to a read out-of-bounds read. To fix this issue, one should jump to descend_to_node if the ptr is a shortcut, regardless of whether the node is root or not. [1] https://lore.kernel.org/linux-kernel/1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com/ [jarkko: tweaked the commit message a bit to have an appropriate closes tag.] | |
Title | security/keys: fix slab-out-of-bounds in key_task_permission | |
References |
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-11-19T01:30:49.982Z
Updated: 2024-12-19T09:37:45.554Z
Reserved: 2024-10-21T19:36:19.987Z
Link: CVE-2024-50301
Vulnrichment
No data.
NVD
Status : Analyzed
Published: 2024-11-19T02:16:32.230
Modified: 2024-11-21T20:53:03.823
Link: CVE-2024-50301
Redhat