Messages in this thread Patch in this message | | | Subject | Re: general protection fault in override_creds | From | Jens Axboe <> | Date | Mon, 2 Dec 2019 08:40:45 -0700 |
| |
On 12/1/19 10:40 PM, Dmitry Vyukov wrote: > On Mon, Dec 2, 2019 at 7:35 AM syzbot > <syzbot+5320383e16029ba057ff@syzkaller.appspotmail.com> wrote: >> >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: b94ae8ad Merge tag 'seccomp-v5.5-rc1' of git://git.kernel... >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=10f9ffcee00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=ff560c3de405258c >> dashboard link: https://syzkaller.appspot.com/bug?extid=5320383e16029ba057ff >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12dd682ae00000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16290abce00000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+5320383e16029ba057ff@syzkaller.appspotmail.com > > I think this relates to fs/io_uring.c rather than kernel/cred.c. > +io_uring maintainers
Yeah that's my fault, guessing the below will fix it. I'll test and queue it up.
diff --git a/fs/io_uring.c b/fs/io_uring.c index ec53aa7cdc94..afafe0463d2d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4361,7 +4361,8 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) io_unaccount_mem(ctx->user, ring_pages(ctx->sq_entries, ctx->cq_entries)); free_uid(ctx->user); - put_cred(ctx->creds); + if (ctx->creds) + put_cred(ctx->creds); kfree(ctx->completions); kmem_cache_free(req_cachep, ctx->fallback_req); kfree(ctx); @@ -4759,7 +4760,12 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) ctx->compat = in_compat_syscall(); ctx->account_mem = account_mem; ctx->user = user; + ctx->creds = prepare_creds(); + if (!ctx->creds) { + ret = -ENOMEM; + goto err; + } ret = io_allocate_scq_urings(ctx, p); if (ret) -- Jens Axboe
| |