"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nraid1: fix use-after-free for original bio in raid1_write_request()\n\nr1_bio->bios[] is used to record new bios that will be issued to\nunderlying disks, however, in raid1_write_request(), r1_bio->bios[]\nwill set to the original bio temporarily. Meanwhile, if blocked rdev\nis set, free_r1bio() will be called causing that all r1_bio->bios[]\nto be freed:\n\nraid1_write_request()\n r1_bio = alloc_r1bio(mddev, bio); -> r1_bio->bios[] is NULL\n for (i = 0; i < disks; i++) -> for each rdev in conf\n // first rdev is normal\n r1_bio->bios[0] = bio; -> set to original bio\n // second rdev is blocked\n if (test_bit(Blocked, &rdev->flags))\n break\n\n if (blocked_rdev)\n free_r1bio()\n put_all_bios()\n bio_put(r1_bio->bios[0]) -> original bio is freed\n\nTest scripts:\n\nmdadm -CR /dev/md0 -l1 -n4 /dev/sd[abcd] --assume-clean\nfio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs=1 \\\n -iodepth=128 -name=test -direct=1\necho blocked > /sys/block/md0/md/rd2/state\n\nTest result:\n\nBUG bio-264 (Not tainted): Object already free\n-----------------------------------------------------------------------------\n\nAllocated in mempool_alloc_slab+0x24/0x50 age=1 cpu=1 pid=869\n kmem_cache_alloc+0x324/0x480\n mempool_alloc_slab+0x24/0x50\n mempool_alloc+0x6e/0x220\n bio_alloc_bioset+0x1af/0x4d0\n blkdev_direct_IO+0x164/0x8a0\n blkdev_write_iter+0x309/0x440\n aio_write+0x139/0x2f0\n io_submit_one+0x5ca/0xb70\n __do_sys_io_submit+0x86/0x270\n __x64_sys_io_submit+0x22/0x30\n do_syscall_64+0xb1/0x210\n entry_SYSCALL_64_after_hwframe+0x6c/0x74\nFreed in mempool_free_slab+0x1f/0x30 age=1 cpu=1 pid=869\n kmem_cache_free+0x28c/0x550\n mempool_free_slab+0x1f/0x30\n mempool_free+0x40/0x100\n bio_free+0x59/0x80\n bio_put+0xf0/0x220\n free_r1bio+0x74/0xb0\n raid1_make_request+0xadf/0x1150\n md_handle_request+0xc7/0x3b0\n md_submit_bio+0x76/0x130\n __submit_bio+0xd8/0x1d0\n submit_bio_noacct_nocheck+0x1eb/0x5c0\n submit_bio_noacct+0x169/0xd40\n submit_bio+0xee/0x1d0\n blkdev_direct_IO+0x322/0x8a0\n blkdev_write_iter+0x309/0x440\n aio_write+0x139/0x2f0\n\nSince that bios for underlying disks are not allocated yet, fix this\nproblem by using mempool_free() directly to free the r1_bio."
"value":"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: raid1: corrige el uso despu\u00e9s de liberar la biograf\u00eda original en raid1_write_request() r1_bio->bios[] se usa para registrar nuevas biograf\u00edas que se emitir\u00e1n a los discos subyacentes; sin embargo, en raid1_write_request(), r1_bio->bios[] se configurar\u00e1 temporalmente en la biograf\u00eda original. Mientras tanto, si se establece rdev bloqueado, se llamar\u00e1 a free_r1bio() causando que todos los r1_bio->bios[] sean liberados: raid1_write_request() r1_bio = alloc_r1bio(mddev, bio); -> r1_bio->bios[] es NULL para (i = 0; i < discos; i++) -> para cada rdev en conf // el primer rdev es normal r1_bio->bios[0] = bio; -> establecer en biograf\u00eda original // el segundo rdev est\u00e1 bloqueado si (test_bit(Blocked, &rdev->flags)) break if (blocked_rdev) free_r1bio() put_all_bios() bio_put(r1_bio->bios[0]) -> biograf\u00eda original es Scripts de prueba liberados: mdadm -CR /dev/md0 -l1 -n4 /dev/sd[abcd] --assume-clean fio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs= 1 \\ -io Depth=128 -name=test -direct=1 eco bloqueado > /sys/block/md0/md/rd2/state Resultado de la prueba: ERROR bio-264 (No contaminado): Objeto ya libre ------ -------------------------------------------------- --------------------- Asignado en mempool_alloc_slab+0x24/0x50 age=1 cpu=1 pid=869 kmem_cache_alloc+0x324/0x480 mempool_alloc_slab+0x24/0x50 mempool_alloc+0x6e /0x220 bio_alloc_bioset+0x1af/0x4d0 blkdev_direct_IO+0x164/0x8a0 blkdev_write_iter+0x309/0x440 aio_write+0x139/0x2f0 io_submit_one+0x5ca/0xb70 __do_sys_io_submit+0x86/0x270 __x64_sys_io_submit+0x22/0x30 do_syscall_64+0xb1/0x210 Entry_SYSCALL_64_after_hwframe+0x6c/0x74 Liberado en mempool_free_slab +0x1f/0x30 edad=1 cpu=1 pid=869 kmem_cache_free+0x28c/0x550 mempool_free_slab+0x1f/0x30 mempool_free+0x40/0x100 bio_free+0x59/0x80 bio_put+0xf0/0x220 free_r1bio+0x74/0xb0 raid1_make_ request+0xadf/0x1150 md_handle_request+ 0xc7/0x3b0 md_submit_bio+0x76/0x130 __submit_bio+0xd8/0x1d0 submit_bio_noacct_nocheck+0x1eb/0x5c0 submit_bio_noacct+0x169/0xd40 submit_bio+0xee/0x1d0 blkdev_direct_IO+0x322/0x8a0 _write_iter+0x309/0x440 aio_write+0x139/0x2f0 Dado que las BIOS para los discos subyacentes son a\u00fan no asignado, solucione este problema usando mempool_free() directamente para liberar r1_bio."