2022-05-16 23:51 GMT+09:00, Tadeusz Struk <tadeusz.struk@xxxxxxxxxx>: > On 5/15/22 07:52, Sungjong Seo wrote: >>> Syzbot reported slab-out-of-bounds read in exfat_clear_bitmap. >>> This was triggered by reproducer calling truncute with size 0, which >>> causes the following trace: >>> >>> BUG: KASAN: slab-out-of-bounds in exfat_clear_bitmap+0x147/0x490 >>> fs/exfat/balloc.c:174 Read of size 8 at addr ffff888115aa9508 by task >>> syz- >>> executor251/365 >>> >>> Call Trace: >>> __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b >>> lib/dump_stack.c:118 >>> print_address_description+0x81/0x3c0 mm/kasan/report.c:233 >>> __kasan_report mm/kasan/report.c:419 [inline] >>> kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436 >>> __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309 >>> exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174 >>> exfat_free_cluster+0x25a/0x4a0 fs/exfat/fatent.c:181 >>> __exfat_truncate+0x99e/0xe00 fs/exfat/file.c:217 >>> exfat_truncate+0x11b/0x4f0 fs/exfat/file.c:243 >>> exfat_setattr+0xa03/0xd40 fs/exfat/file.c:339 >>> notify_change+0xb76/0xe10 fs/attr.c:336 >>> do_truncate+0x1ea/0x2d0 fs/open.c:65 >>> >>> Add checks to validate if cluster number is within valid range in >>> exfat_clear_bitmap() and exfat_set_bitmap() >>> >>> Cc: Namjae Jeon<linkinjeon@xxxxxxxxxx> >>> Cc: Sungjong Seo<sj1557.seo@xxxxxxxxxxx> >>> Cc:linux-fsdevel@xxxxxxxxxxxxxxx >>> Cc:stable@xxxxxxxxxxxxxxx >>> Cc:linux-kernel@xxxxxxxxxxxxxxx >>> >>> Link:https://protect2.fireeye.com/v1/url?k=24a746d8-45dcec51-24a6cd97- >>> 74fe48600034-8e4653a49a463f3c&q=1&e=0efc824d-6463-4253-9cd7- >>> ce3199dbf513&u=https%3A%2F%2Fsyzkaller.appspot.com%2Fbug%3Fid%3D50381fc738 >>> 21ecae743b8cf24b4c9a04776f767c >>> Reported-by:syzbot+a4087e40b9c13aad7892@xxxxxxxxxxxxxxxxxxxxxxxxx >>> Fixes: 1e49a94cf707 ("exfat: add bitmap operations") >>> Signed-off-by: Tadeusz Struk<tadeusz.struk@xxxxxxxxxx> >> Looks good. >> And it seems that WARN_ON() is no longer needed. > > Right. Do you want me to send a follow up patch that drops the WARN_ONs? You don't need to do it. I have applied this patch to #exfat dev branch after removing it. Note that I have combined 1/2 into 2/2 patch. Thanks! > >> Reviewed-by: Sungjong Seo<sj1557.seo@xxxxxxxxxxx> >> > > Thank you. > > -- > Thanks, > Tadeusz >
