{"id":"CVE-2021-47615","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Fix releasing unallocated memory in dereg MR flow\n\nFor the case of IB_MR_TYPE_DM the mr does doesn't have a umem, even though\nit is a user MR. This causes function mlx5_free_priv_descs() to think that\nit is a kernel MR, leading to wrongly accessing mr-\u003edescs that will get\nwrong values in the union which leads to attempt to release resources that\nwere not allocated in the first place.\n\nFor example:\n DMA-API: mlx5_core 0000:08:00.1: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=0 bytes]\n WARNING: CPU: 8 PID: 1021 at kernel/dma/debug.c:961 check_unmap+0x54f/0x8b0\n RIP: 0010:check_unmap+0x54f/0x8b0\n Call Trace:\n  debug_dma_unmap_page+0x57/0x60\n  mlx5_free_priv_descs+0x57/0x70 [mlx5_ib]\n  mlx5_ib_dereg_mr+0x1fb/0x3d0 [mlx5_ib]\n  ib_dereg_mr_user+0x60/0x140 [ib_core]\n  uverbs_destroy_uobject+0x59/0x210 [ib_uverbs]\n  uobj_destroy+0x3f/0x80 [ib_uverbs]\n  ib_uverbs_cmd_verbs+0x435/0xd10 [ib_uverbs]\n  ? uverbs_finalize_object+0x50/0x50 [ib_uverbs]\n  ? lock_acquire+0xc4/0x2e0\n  ? lock_acquired+0x12/0x380\n  ? lock_acquire+0xc4/0x2e0\n  ? lock_acquire+0xc4/0x2e0\n  ? ib_uverbs_ioctl+0x7c/0x140 [ib_uverbs]\n  ? lock_release+0x28a/0x400\n  ib_uverbs_ioctl+0xc0/0x140 [ib_uverbs]\n  ? ib_uverbs_ioctl+0x7c/0x140 [ib_uverbs]\n  __x64_sys_ioctl+0x7f/0xb0\n  do_syscall_64+0x38/0x90\n\nFix it by reorganizing the dereg flow and mlx5_ib_mr structure:\n - Move the ib_umem field into the user MRs structure in the union as it's\n   applicable only there.\n - Function mlx5_ib_dereg_mr() will now call mlx5_free_priv_descs() only\n   in case there isn't udata, which indicates that this isn't a user MR.","modified":"2024-12-19T15:41:50.999836Z","published":"2024-06-19T15:15:56Z","withdrawn":"2024-12-19T15:41:50.999836Z","related":["SUSE-SU-2024:2372-1","SUSE-SU-2024:2394-1","SUSE-SU-2024:2902-1","SUSE-SU-2024:2929-1","SUSE-SU-2024:2939-1"],"references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/c44979ace49b4aede3cc7cb5542316e53a4005c9"},{"type":"FIX","url":"https://git.kernel.org/stable/c/e3bc4d4b50cae7db08e50dbe43f771c906e97701"},{"type":"FIX","url":"https://git.kernel.org/stable/c/f0ae4afe3d35e67db042c58a52909e06262b740f"},{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2021-47615"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47615.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47615.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}