"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix NULL pointer dereference in nilfs_palloc_commit_free_entry()\n\nSyzbot reported a null-ptr-deref bug:\n\n NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP\n frequency < 30 seconds\n general protection fault, probably for non-canonical address\n 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN\n KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]\n CPU: 1 PID: 3603 Comm: segctord Not tainted\n 6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0\n Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google\n 10/11/2022\n RIP: 0010:nilfs_palloc_commit_free_entry+0xe5/0x6b0\n fs/nilfs2/alloc.c:608\n Code: 00 00 00 00 fc ff df 80 3c 02 00 0f 85 cd 05 00 00 48 b8 00 00 00\n 00 00 fc ff df 4c 8b 73 08 49 8d 7e 10 48 89 fa 48 c1 ea 03 <80> 3c 02\n 00 0f 85 26 05 00 00 49 8b 46 10 be a6 00 00 00 48 c7 c7\n RSP: 0018:ffffc90003dff830 EFLAGS: 00010212\n RAX: dffffc0000000000 RBX: ffff88802594e218 RCX: 000000000000000d\n RDX: 0000000000000002 RSI: 0000000000002000 RDI: 0000000000000010\n RBP: ffff888071880222 R08: 0000000000000005 R09: 000000000000003f\n R10: 000000000000000d R11: 0000000000000000 R12: ffff888071880158\n R13: ffff88802594e220 R14: 0000000000000000 R15: 0000000000000004\n FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000)\n knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007fb1c08316a8 CR3: 0000000018560000 CR4: 0000000000350ee0\n Call Trace:\n <TASK>\n nilfs_dat_commit_free fs/nilfs2/dat.c:114 [inline]\n nilfs_dat_commit_end+0x464/0x5f0 fs/nilfs2/dat.c:193\n nilfs_dat_commit_update+0x26/0x40 fs/nilfs2/dat.c:236\n nilfs_btree_commit_update_v+0x87/0x4a0 fs/nilfs2/btree.c:1940\n nilfs_btree_commit_propagate_v fs/nilfs2/btree.c:2016 [inline]\n nilfs_btree_propagate_v fs/nilfs2/btree.c:2046 [inline]\n nilfs_btree_propagate+0xa00/0xd60 fs/nilfs2/btree.c:2088\n nilfs_bmap_propagate+0x73/0x170 fs/nilfs2/bmap.c:337\n nilfs_collect_file_data+0x45/0xd0 fs/nilfs2/segment.c:568\n nilfs_segctor_apply_buffers+0x14a/0x470 fs/nilfs2/segment.c:1018\n nilfs_segctor_scan_file+0x3f4/0x6f0 fs/nilfs2/segment.c:1067\n nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1197 [inline]\n nilfs_segctor_collect fs/nilfs2/segment.c:1503 [inline]\n nilfs_segctor_do_construct+0x12fc/0x6af0 fs/nilfs2/segment.c:2045\n nilfs_segctor_construct+0x8e3/0xb30 fs/nilfs2/segment.c:2379\n nilfs_segctor_thread_construct fs/nilfs2/segment.c:2487 [inline]\n nilfs_segctor_thread+0x3c3/0xf30 fs/nilfs2/segment.c:2570\n kthread+0x2e4/0x3a0 kernel/kthread.c:376\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306\n </TASK>\n ...\n\nIf DAT metadata file is corrupted on disk, there is a case where\nreq->pr_desc_bh is NULL and blocknr is 0 at nilfs_dat_commit_end() during\na b-tree operation that cascadingly updates ancestor nodes of the b-tree,\nbecause nilfs_dat_commit_alloc() for a lower level block can initialize\nthe blocknr on the same DAT entry between nilfs_dat_prepare_end() and\nnilfs_dat_commit_end().\n\nIf this happens, nilfs_dat_commit_end() calls nilfs_dat_commit_free()\nwithout valid buffer heads in req->pr_desc_bh and req->pr_bitmap_bh, and\ncauses the NULL pointer dereference above in\nnilfs_palloc_commit_free_entry() function, which leads to a crash.\n\nFix this by adding a NULL check on req->pr_desc_bh and req->pr_bitmap_bh\nbefore nilfs_palloc_commit_free_entry() in nilfs_dat_commit_free().\n\nThis also calls nilfs_error() in that case to notify that there is a fatal\nflaw in the filesystem metadata and prevent further operations."
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nilfs2: corrige la desreferencia de puntero NULL en nilfs_palloc_commit_free_entry() Syzbot inform\u00f3 un error de desreferencia de puntero nulo: NILFS (loop0): segctord iniciando. Intervalo de construcci\u00f3n = 5 segundos, frecuencia de CP < 30 segundos. fallo de protecci\u00f3n general, probablemente para direcci\u00f3n no can\u00f3nica 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref en rango [0x000000000000010-0x0000000000000017] CPU: 1 PID: 3603 Comm: segctord No contaminado 6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0 Nombre del hardware: Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 RIP: 0010:nilfs_palloc_commit_free_entry+0xe5/0x6b0 fs/nilfs2/alloc.c:608 C\u00f3digo: 00 00 00 00 fc ff df 80 3c 02 00 0f 85 cd 05 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 73 08 49 8d 7e 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 26 05 00 00 49 8b 46 10 ser a6 00 00 00 48 c7 c7 RSP: 0018:ffffc90003dff830 EFLAGS: 00010212 RAX: dffffc00000000000 RBX: ffff88802594e218 RCX: 000000000000000d RDX: 00000000000000002 RSI: 0000000000002000 RDI: 0000000000000010 RBP: ffff888071880222 R08: 000000000000005 R09: 000000000000003f R10: 000000000000000d R11: 0000000000000000 R12: ffff888071880158 R13: ffff88802594e220 R14: 0000000000000000 R15: 0000000000000004 FS: 000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1c08316a8 CR3: 0000000018560000 CR4: 0000000000350ee0 Seguimiento de llamadas: nilfs_dat_commit_free fs/nilfs2/dat.c:114 [en l\u00ednea] nilfs_dat_commit_end+0x464/0x5f0 fs/nilfs2/dat.c:193 nilfs_dat_commit_update+0x26/0x40 fs/nilfs2/dat.c:236 nilfs_btree_commit_update_v+0x87/0x4a0 fs/nilfs2/btree.c:1940 nilfs_btree_commit_propagate_v fs/nilfs2/btree.c:2016 [en l\u00ednea] nilfs_btree_propagate_v fs/nilfs2/btree.c:2046 [en l\u00ednea] nilfs_btree_propagate+0xa00/0xd60 fs/nilfs2/btree.c:2088 nilfs_bmap_propagate+0x73/0x170 fs/nilfs2/bmap.c:337 nilfs_collect_file_data+0x45/0xd0 fs/nilfs2/segment.c:568 nilfs_segctor_apply_buffers+0x14a/0x470 fs/nilfs2/segment.c:1018 nilfs_segctor_scan_file+0x3f4/0x6f0 fs/nilfs2/segment.c:1067 nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1197 [en l\u00ednea] nilfs_segctor_collect fs/nilfs2/segment.c:1503 [en l\u00ednea] nilfs_segctor_do_construct+0x12fc/0x6af0 fs/nilfs2/segment.c:2045 nilfs_segctor_construct+0x8e3/0xb30 fs/nilfs2/segment.c:2379 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2487 [en l\u00ednea] nilfs_segctor_thread+0x3c3/0xf30 fs/nilfs2/segment.c:2570 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 ... Si el archivo de metadatos DAT est\u00e1 da\u00f1ado en el disco, existe un caso en el que req->pr_desc_bh es NULL y blocknr es 0 en nilfs_dat_commit_end() durante una operaci\u00f3n de \u00e1rbol b que actualiza en cascada los nodos ancestros del \u00e1rbol b, porque nilfs_dat_commit_alloc() para un bloque de nivel inferior puede inicializar el blocknr en la misma entrada DAT entre nilfs_dat_prepare_end() y nilfs_dat_commit_end(). Si esto sucede, nilfs_dat_commit_end() llama a nilfs_dat_commit_free() sin encabezados de b\u00fafer v\u00e1lidos en req->pr_desc_bh y req->pr_bitmap_bh, y provoca la desreferencia del puntero NULL anterior en la funci\u00f3n nilfs_palloc_commit_free_entry(), lo que provoca un bloqueo. Solucione este problema agregando una comprobaci\u00f3n NULL en req->pr_desc_bh y req->pr_bitmap_bh antes de nilfs_palloc_commit_free_entry() en nilfs_dat_commit_free(). Esto tambi\u00e9n llama a nilfs_error() en ese caso para notificar que hay un fallo fatal en los metadatos del sistema de archivos y evitar operaciones futuras."