CVE-2024-26657

Published Apr 2, 2024

Last updated 2 years ago

CVSS medium 5.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: drm/sched: fix null-ptr-deref in init entity The bug can be triggered by sending an amdgpu_cs_wait_ioctl to the AMDGPU DRM driver on any ASICs with valid context. The bug was reported by Joonkyo Jung <joonkyoj@yonsei.ac.kr>. For example the following code: static void Syzkaller2(int fd) { union drm_amdgpu_ctx arg1; union drm_amdgpu_wait_cs arg2; arg1.in.op = AMDGPU_CTX_OP_ALLOC_CTX; ret = drmIoctl(fd, 0x140106442 /* amdgpu_ctx_ioctl */, &arg1); arg2.in.handle = 0x0; arg2.in.timeout = 0x2000000000000; arg2.in.ip_type = AMD_IP_VPE /* 0x9 */; arg2->in.ip_instance = 0x0; arg2.in.ring = 0x0; arg2.in.ctx_id = arg1.out.alloc.ctx_id; drmIoctl(fd, 0xc0206449 /* AMDGPU_WAIT_CS * /, &arg2); } The ioctl AMDGPU_WAIT_CS without previously submitted job could be assumed that the error should be returned, but the following commit 1decbf6bb0b4dc56c9da6c5e57b994ebfc2be3aa modified the logic and allowed to have sched_rq equal to NULL. As a result when there is no job the ioctl AMDGPU_WAIT_CS returns success. The change fixes null-ptr-deref in init entity and the stack below demonstrates the error condition: [ +0.000007] BUG: kernel NULL pointer dereference, address: 0000000000000028 [ +0.007086] #PF: supervisor read access in kernel mode [ +0.005234] #PF: error_code(0x0000) - not-present page [ +0.005232] PGD 0 P4D 0 [ +0.002501] Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI [ +0.005034] CPU: 10 PID: 9229 Comm: amd_basic Tainted: G B W L 6.7.0+ #4 [ +0.007797] Hardware name: ASUS System Product Name/ROG STRIX B550-F GAMING (WI-FI), BIOS 1401 12/03/2020 [ +0.009798] RIP: 0010:drm_sched_entity_init+0x2d3/0x420 [gpu_sched] [ +0.006426] Code: 80 00 00 00 00 00 00 00 e8 1a 81 82 e0 49 89 9c 24 c0 00 00 00 4c 89 ef e8 4a 80 82 e0 49 8b 5d 00 48 8d 7b 28 e8 3d 80 82 e0 <48> 83 7b 28 00 0f 84 28 01 00 00 4d 8d ac 24 98 00 00 00 49 8d 5c [ +0.019094] RSP: 0018:ffffc90014c1fa40 EFLAGS: 00010282 [ +0.005237] RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8113f3fa [ +0.007326] RDX: fffffbfff0a7889d RSI: 0000000000000008 RDI: ffffffff853c44e0 [ +0.007264] RBP: ffffc90014c1fa80 R08: 0000000000000001 R09: fffffbfff0a7889c [ +0.007266] R10: ffffffff853c44e7 R11: 0000000000000001 R12: ffff8881a719b010 [ +0.007263] R13: ffff88810d412748 R14: 0000000000000002 R15: 0000000000000000 [ +0.007264] FS: 00007ffff7045540(0000) GS:ffff8883cc900000(0000) knlGS:0000000000000000 [ +0.008236] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.005851] CR2: 0000000000000028 CR3: 000000011912e000 CR4: 0000000000350ef0 [ +0.007175] Call Trace: [ +0.002561] <TASK> [ +0.002141] ? show_regs+0x6a/0x80 [ +0.003473] ? __die+0x25/0x70 [ +0.003124] ? page_fault_oops+0x214/0x720 [ +0.004179] ? preempt_count_sub+0x18/0xc0 [ +0.004093] ? __pfx_page_fault_oops+0x10/0x10 [ +0.004590] ? srso_return_thunk+0x5/0x5f [ +0.004000] ? vprintk_default+0x1d/0x30 [ +0.004063] ? srso_return_thunk+0x5/0x5f [ +0.004087] ? vprintk+0x5c/0x90 [ +0.003296] ? drm_sched_entity_init+0x2d3/0x420 [gpu_sched] [ +0.005807] ? srso_return_thunk+0x5/0x5f [ +0.004090] ? _printk+0xb3/0xe0 [ +0.003293] ? __pfx__printk+0x10/0x10 [ +0.003735] ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 [ +0.005482] ? do_user_addr_fault+0x345/0x770 [ +0.004361] ? exc_page_fault+0x64/0xf0 [ +0.003972] ? asm_exc_page_fault+0x27/0x30 [ +0.004271] ? add_taint+0x2a/0xa0 [ +0.003476] ? drm_sched_entity_init+0x2d3/0x420 [gpu_sched] [ +0.005812] amdgpu_ctx_get_entity+0x3f9/0x770 [amdgpu] [ +0.009530] ? finish_task_switch.isra.0+0x129/0x470 [ +0.005068] ? __pfx_amdgpu_ctx_get_entity+0x10/0x10 [amdgpu] [ +0.010063] ? __kasan_check_write+0x14/0x20 [ +0.004356] ? srso_return_thunk+0x5/0x5f [ +0.004001] ? mutex_unlock+0x81/0xd0 [ +0.003802] ? srso_return_thunk+0x5/0x5f [ +0.004096] amdgpu_cs_wait_ioctl+0xf6/0x270 [amdgpu] [ +0.009355] ? __pfx_ ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. In the Linux kernel, the following vulnerability has been resolved: ipv4: account for fraggap on the paged allocation path In __ip_append_data(), when the paged-allocation branch is taken, alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap, but the fraggap bytes carried over from the previous skb are copied into the new skb's linear area at offset transhdrlen by the subsequent skb_copy_and_csum_bits(). The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic.•CVE-2026-53366
  2. In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: fix zerocopy completion for multi-skb sends When a large message is fragmented into multiple skbs, the zerocopy uarg is only allocated and attached to the last skb in the loop. Non-final skbs carry pinned user pages with no completion tracking, so the kernel has no way to notify userspace when those pages are safe to reuse. If the loop breaks early the uarg is never allocated at all, leaking pinned pages with no completion notification. Fix this by following the approach used by TCP: allocate the zerocopy uarg (if not provided by the caller) before the send loop and attach it to every skb via skb_zcopy_set(), which takes a reference per skb. Each skb's completion properly decrements the refcount, and the notification only fires after the last skb is freed. On failure, if no data was sent, the uarg is cleanly aborted via net_zcopy_put_abort(). This issue was initially discovered by sashiko while reviewing commit 1cb36e252211 ("vsock/virtio: fix MSG_ZEROCOPY pinned-pages accounting") but was pre-existing.•CVE-2026-53365
  3. In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: Fix memory leak in hci_le_big_terminate() hci_le_big_terminate() allocates iso_list_data via kzalloc_obj but returns 0 without freeing it when neither pa_sync_term nor big_sync_term flags are set after evaluating the PA and BIG sync connection state. This early-return path was introduced when hci_le_big_terminate() was refactored to take struct hci_conn instead of raw u8 parameters, adding PA/BIG flag evaluation logic. The existing kfree() on hci_cmd_sync_queue failure does not cover this path.•CVE-2026-53364
  4. In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags() iptfs_consume_frags() transfers paged fragments from one socket buffer to another but fails to propagate the SKBFL_SHARED_FRAG flag. This is the same class of bug that was fixed in skb_try_coalesce() for CVE-2026-46300: when fragments backed by read-only page-cache pages are merged, the marker indicating their shared nature must be preserved so that ESP can decide correctly whether in-place encryption is safe. Apply the same two-line fix used in skb_try_coalesce() to iptfs_consume_frags().•CVE-2026-53363
  5. In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.•CVE-2026-53362

References

Sources include official advisories and independent security research.