CVE-2022-50884
Description
In the Linux kernel, the following vulnerability has been resolved:
drm: Prevent drm_copy_field() to attempt copying a NULL pointer
There are some struct drm_driver fields that are required by drivers since drm_copy_field() attempts to copy them to user-space via DRM_IOCTL_VERSION.
But it can be possible that a driver has a bug and did not set some of the fields, which leads to drm_copy_field() attempting to copy a NULL pointer:
[ +10.395966] Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000000 [ +0.010955] Mem abort info: [ +0.002835] ESR = 0x0000000096000004 [ +0.003872] EC = 0x25: DABT (current EL), IL = 32 bits [ +0.005395] SET = 0, FnV = 0 [ +0.003113] EA = 0, S1PTW = 0 [ +0.003182] FSC = 0x04: level 0 translation fault [ +0.004964] Data abort info: [ +0.002919] ISV = 0, ISS = 0x00000004 [ +0.003886] CM = 0, WnR = 0 [ +0.003040] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000115dad000 [ +0.006536] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ +0.006925] Internal error: Oops: 96000004 [#1] SMP ... [ +0.011113] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ +0.007061] pc : __pi_strlen+0x14/0x150 [ +0.003895] lr : drm_copy_field+0x30/0x1a4 [ +0.004156] sp : ffff8000094b3a50 [ +0.003355] x29: ffff8000094b3a50 x28: ffff8000094b3b70 x27: 0000000000000040 [ +0.007242] x26: ffff443743c2ba00 x25: 0000000000000000 x24: 0000000000000040 [ +0.007243] x23: ffff443743c2ba00 x22: ffff8000094b3b70 x21: 0000000000000000 [ +0.007241] x20: 0000000000000000 x19: ffff8000094b3b90 x18: 0000000000000000 [ +0.007241] x17: 0000000000000000 x16: 0000000000000000 x15: 0000aaab14b9af40 [ +0.007241] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ +0.007239] x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa524ad67d4d8 [ +0.007242] x8 : 0101010101010101 x7 : 7f7f7f7f7f7f7f7f x6 : 6c6e6263606e7141 [ +0.007239] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 [ +0.007241] x2 : 0000000000000000 x1 : ffff8000094b3b90 x0 : 0000000000000000 [ +0.007240] Call trace: [ +0.002475] __pi_strlen+0x14/0x150 [ +0.003537] drm_version+0x84/0xac [ +0.003448] drm_ioctl_kernel+0xa8/0x16c [ +0.003975] drm_ioctl+0x270/0x580 [ +0.003448] __arm64_sys_ioctl+0xb8/0xfc [ +0.003978] invoke_syscall+0x78/0x100 [ +0.003799] el0_svc_common.constprop.0+0x4c/0xf4 [ +0.004767] do_el0_svc+0x38/0x4c [ +0.003357] el0_svc+0x34/0x100 [ +0.003185] el0t_64_sync_handler+0x11c/0x150 [ +0.004418] el0t_64_sync+0x190/0x194 [ +0.003716] Code: 92402c04 b200c3e8 f13fc09f 5400088c (a9400c02) [ +0.006180] ---[ end trace 0000000000000000 ]---
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
The Linux kernel's DRM subsystem fails to null-check driver fields in drm_copy_field(), allowing a local attacker to trigger a NULL pointer dereference via the DRM_IOCTL_VERSION ioctl.
Vulnerability
Overview
CVE-2022-50884 is a NULL pointer dereference vulnerability in the Linux kernel's Direct Rendering Manager (DRM) subsystem. The function drm_copy_field() attempts to copy several struct drm_driver fields — such as the driver name, date, or description — to user space via the DRM_IOCTL_VERSION ioctl. If a driver fails to initialize any of these required fields, the kernel will attempt to pass a NULL pointer to strlen(), leading to an immediate kernel crash (Oops) [1].
Attack
Vector and Prerequisites
The vulnerability is triggered by a user-space application issuing the DRM_IOCTL_VERSION ioctl against a DRM device backed by a driver that has not properly set all required fields in its drm_driver structure. No special privileges beyond access to the DRM device node are needed; the ioctl is typically accessible to members of the video group. The crash occurs in kernel context, making it a local denial-of-service vector [2].
Impact
A local unprivileged user can exploit this bug to cause a kernel NULL pointer dereference, resulting in a system crash (denial of service). The vulnerability does not provide code execution or privilege escalation; its primary consequence is system instability and availability loss [3].
Mitigation
Patches have been applied to the stable kernel tree, adding a NULL check before each string copy in drm_copy_field() [4]. Users should update their kernels to versions containing the fix. No workaround short of applying the patch is known [1][4].
AI Insight generated on May 19, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
1Patches
9d213914386a0ee9885cd936a8052612b9d08cdde55f97298c28a8082b25cca163e389f0a2d6708ea5c206cf5e9356b2df6ee30407e88Vulnerability mechanics
Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
9- git.kernel.org/stable/c/2d6708ea5c2033ff53267feff1876a717689989fnvd
- git.kernel.org/stable/c/6cf5e9356b2d856403ee480f987f3ea64dbf8d8cnvd
- git.kernel.org/stable/c/8052612b9d08048ebbebcb572894670b4ac07d2fnvd
- git.kernel.org/stable/c/c28a8082b25ce4ec94999e10a30c50d20bd44a25nvd
- git.kernel.org/stable/c/ca163e389f0ae096a4e1e19f0a95e60ed80b4e31nvd
- git.kernel.org/stable/c/cdde55f97298e5bb9af6d41c9303a3ec545a370envd
- git.kernel.org/stable/c/d213914386a0ede76a4549b41de30192fb92c595nvd
- git.kernel.org/stable/c/ee9885cd936aad88f84d0cf90bf9a70e83e42a97nvd
- git.kernel.org/stable/c/f6ee30407e883042482ad4ad30da5eaba47872eenvd
News mentions
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