CVE: CVE-2024-56615
Published: 2024-12-27
Description: In the Linux kernel, the following vulnerability has been resolved:

bpf: fix OOB devmap writes when deleting elements

Jordy reported issue against XSKMAP which also applies to DEVMAP - the
index used for accessing map entry, due to being a signed integer,
causes the OOB writes. Fix is simple as changing the type from int to
u32, however, when compared to XSKMAP case, one more thing needs to be
addressed.

When map is released from system via dev_map_free(), we iterate through
all of the entries and an iterator variable is also an int, which
implies OOB accesses. Again, change it to be u32.

Example splat below:

[  160.724676] BUG: unable to handle page fault for address: ffffc8fc2c001000
[  160.731662] #PF: supervisor read access in kernel mode
[  160.736876] #PF: error_code(0x0000) - not-present page
[  160.742095] PGD 0 P4D 0
[  160.744678] Oops: Oops: 0000 [#1] PREEMPT SMP
[  160.749106] CPU: 1 UID: 0 PID: 520 Comm: kworker/u145:12 Not tainted 6.12.0-rc1+ #487
[  160.757050] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0[PII_REDACTED]91559 03/19/2019
[  160.767642] Workqueue: events_unbound bpf_map_free_deferred
[  160.773308] RIP: 0010:dev_map_free+0x77/0x170
[  160.777735] Code: 00 e8 fd 91 ed ff e8 b8 73 ed ff 41 83 7d 18 19 74 6e 41 8b 45 24 49 8b bd f8 00 00 00 31 db 85 c0 74 48 48 63 c3 48 8d 04 c7 <48> 8b 28 48 85 ed 74 30 48 8b 7d 18 48 85 ff 74 05 e8 b3 52 fa ff
[  160.796777] RSP: 0018:ffffc9000ee1fe38 EFLAGS: 00010202
[  160.802086] RAX: ffffc8fc2c001000 RBX: [PII_REDACTED] RCX: [PII_REDACTED]
[  160.809331] RDX: [PII_REDACTED] RSI: [PII_REDACTED] RDI: ffffc9002c001000
[  160.816576] RBP: [PII_REDACTED] R08: [PII_REDACTED] R09: [PII_REDACTED]
[  160.823823] R10: [PII_REDACTED] R11:[PII_REDACTED]0ee6b2 R12: dead[PII_REDACTED]22
[  160.831066] R13: ffff88810c928e00 R14: ffff8881002df405 R15: [PII_REDACTED]
[  160.838310] FS:  [PII_REDACTED](0000) GS:ffff8897e0c40000(0000) knlGS:[PII_REDACTED]
[  160.846528] CS:  0010 DS: 0000 ES: 0000 CR0: [PII_REDACTED]
[  160.852357] CR2: ffffc8fc2c001000 CR3:[PII_REDACTED]c32006 CR4:[PII_REDACTED]7726f0
[  160.859604] DR0: [PII_REDACTED] DR1: [PII_REDACTED] DR2: [PII_REDACTED]
[  160.866847] DR3: [PII_REDACTED] DR6: 00000000fffe0ff0 DR7: [PII_REDACTED]
[  160.874092] PKRU: 55555554
[  160.876847] Call Trace:
[  160.879338]  <TASK>
[  160.881477]  ? __die+0x20/0x60
[  160.884586]  ? page_fault_oops+0x15a/0x450
[  160.888746]  ? search_extable+0x22/0x30
[  160.892647]  ? search_bpf_extables+0x5f/0x80
[  160.896988]  ? exc_page_fault+0xa9/0x140
[  160.900973]  ? asm_exc_page_fault+0x22/0x30
[  160.905232]  ? dev_map_free+0x77/0x170
[  160.909043]  ? dev_map_free+0x58/0x170
[  160.912857]  bpf_map_free_deferred+0x51/0x90
[  160.917196]  process_one_work+0x142/0x370
[  160.921272]  worker_thread+0x29e/0x3b0
[  160.925082]  ? rescuer_thread+0x4b0/0x4b0
[  160.929157]  kthread+0xd4/0x110
[  160.932355]  ? kthread_park+0x80/0x80
[  160.936079]  ret_from_fork+0x2d/0x50
[  160.943396]  ? kthread_park+0x80/0x80
[  160.950803]  ret_from_fork_asm+0x11/0x20
[  160.958482]  </TASK>
CVSS Score: 7.8 (HIGH)
CWE: CWE-787, CWE-787
References: https://git.kernel.org/stable/c/0f170e91d3063ca60baec4bd9f544faf3bfe29eb; https://git.kernel.org/stable/c/178e31df1fb3d9e0890eb471da16709cbc82edee; https://git.kernel.org/stable/c/70f3de869865f9c3da0508a5ea29f6f4c1889057