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Chen Ridong 4efb69a0e2 security/keys: fix slab-out-of-bounds in key_task_permission
[ Upstream commit 4a74da044ec9ec8679e6beccc4306b936b62873f ]

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.]
Fixes: b2a4df200d ("KEYS: Expand the capacity of a keyring")
Reported-by: syzbot+5b415c07907a2990d1a3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000cbb7860611f61147@google.com/T/
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-17 14:58:50 +01:00
arch ARM: dts: rockchip: Fix the realtek audio codec on rk3036-kylin 2024-11-17 14:58:50 +01:00
block blk-rq-qos: fix crash on rq_qos_wait vs. rq_qos_wake_function race 2024-11-08 16:20:48 +01:00
certs
crypto crypto: aead,cipher - zeroize key buffer after use 2024-11-08 16:20:33 +01:00
Documentation dt-bindings: gpu: Convert Samsung Image Rotator to dt-schema 2024-11-08 16:20:52 +01:00
drivers HID: core: zero-initialize the report buffer 2024-11-17 14:58:50 +01:00
fs nilfs2: fix kernel bug due to missing clearing of checked flag 2024-11-08 16:20:54 +01:00
include mac80211: Add support to trigger sta disconnect on hardware restart 2024-11-08 16:20:52 +01:00
init init: open /initrd.image with O_LARGEFILE 2024-04-13 12:51:36 +02:00
ipc ipc: replace costly bailout check in sysvipc_find_ipc() 2024-09-04 13:15:02 +02:00
kernel bpf: Fix out-of-bounds write in trie_get_next_key() 2024-11-08 16:20:52 +01:00
lib debugobjects: Fix conditions in fill_pool() 2024-11-08 16:20:34 +01:00
LICENSES
mm mm: krealloc: Fix MTE false alarm in __do_krealloc 2024-11-08 16:20:54 +01:00
net mac80211: always have ieee80211_sta_restart() 2024-11-08 16:20:54 +01:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
scripts scripts: kconfig: merge_config: config files: add a trailing newline 2024-11-08 16:20:24 +01:00
security security/keys: fix slab-out-of-bounds in key_task_permission 2024-11-17 14:58:50 +01:00
sound ASoC: cs42l51: Fix some error handling paths in cs42l51_probe() 2024-11-08 16:20:52 +01:00
tools usbip: tools: Fix detach_port() invalid port error path 2024-11-08 16:20:53 +01:00
usr
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-11-08 16:20:47 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.285 2024-11-08 16:20:54 +01:00
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