From 74e2e17ee1f8d8a0928b90434ad7e2df70f8483e Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 20 Mar 2023 11:13:49 -0600 Subject: [PATCH 1/2] io_uring/net: avoid sending -ECONNABORTED on repeated connection requests Since io_uring does nonblocking connect requests, if we do two repeated ones without having a listener, the second will get -ECONNABORTED rather than the expected -ECONNREFUSED. Treat -ECONNABORTED like a normal retry condition if we're nonblocking, if we haven't already seen it. Cc: stable@vger.kernel.org Fixes: 3fb1bd688172 ("io_uring/net: handle -EINPROGRESS correct for IORING_OP_CONNECT") Link: https://github.com/axboe/liburing/issues/828 Reported-by: Hui, Chunyang Signed-off-by: Jens Axboe --- io_uring/net.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/io_uring/net.c b/io_uring/net.c index b7f190ca528e..4040cf093318 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -47,6 +47,7 @@ struct io_connect { struct sockaddr __user *addr; int addr_len; bool in_progress; + bool seen_econnaborted; }; struct io_sr_msg { @@ -1424,7 +1425,7 @@ int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); conn->addr_len = READ_ONCE(sqe->addr2); - conn->in_progress = false; + conn->in_progress = conn->seen_econnaborted = false; return 0; } @@ -1461,18 +1462,24 @@ int io_connect(struct io_kiocb *req, unsigned int issue_flags) ret = __sys_connect_file(req->file, &io->address, connect->addr_len, file_flags); - if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) { + if ((ret == -EAGAIN || ret == -EINPROGRESS || ret == -ECONNABORTED) + && force_nonblock) { if (ret == -EINPROGRESS) { connect->in_progress = true; - } else { - if (req_has_async_data(req)) - return -EAGAIN; - if (io_alloc_async_data(req)) { - ret = -ENOMEM; - goto out; - } - memcpy(req->async_data, &__io, sizeof(__io)); + return -EAGAIN; } + if (ret == -ECONNABORTED) { + if (connect->seen_econnaborted) + goto out; + connect->seen_econnaborted = true; + } + if (req_has_async_data(req)) + return -EAGAIN; + if (io_alloc_async_data(req)) { + ret = -ENOMEM; + goto out; + } + memcpy(req->async_data, &__io, sizeof(__io)); return -EAGAIN; } if (ret == -ERESTARTSYS) From 02a4d923e4400a36d340ea12d8058f69ebf3a383 Mon Sep 17 00:00:00 2001 From: Savino Dicanosa Date: Tue, 21 Mar 2023 19:44:02 +0000 Subject: [PATCH 2/2] io_uring/rsrc: fix null-ptr-deref in io_file_bitmap_get() When fixed files are unregistered, file_alloc_end and alloc_hint are not cleared. This can later cause a NULL pointer dereference in io_file_bitmap_get() if auto index selection is enabled via IORING_FILE_INDEX_ALLOC: [ 6.519129] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] [ 6.541468] RIP: 0010:_find_next_zero_bit+0x1a/0x70 [...] [ 6.560906] Call Trace: [ 6.561322] [ 6.561672] io_file_bitmap_get+0x38/0x60 [ 6.562281] io_fixed_fd_install+0x63/0xb0 [ 6.562851] ? __pfx_io_socket+0x10/0x10 [ 6.563396] io_socket+0x93/0xf0 [ 6.563855] ? __pfx_io_socket+0x10/0x10 [ 6.564411] io_issue_sqe+0x5b/0x3d0 [ 6.564914] io_submit_sqes+0x1de/0x650 [ 6.565452] __do_sys_io_uring_enter+0x4fc/0xb20 [ 6.566083] ? __do_sys_io_uring_register+0x11e/0xd80 [ 6.566779] do_syscall_64+0x3c/0x90 [ 6.567247] entry_SYSCALL_64_after_hwframe+0x72/0xdc [...] To fix the issue, set file alloc range and alloc_hint to zero after file tables are freed. Cc: stable@vger.kernel.org Fixes: 4278a0deb1f6 ("io_uring: defer alloc_hint update to io_file_bitmap_set()") Signed-off-by: Savino Dicanosa [axboe: add explicit bitmap == NULL check as well] Signed-off-by: Jens Axboe --- io_uring/filetable.c | 3 +++ io_uring/rsrc.c | 1 + 2 files changed, 4 insertions(+) diff --git a/io_uring/filetable.c b/io_uring/filetable.c index 68dfc6936aa7..b80614e7d605 100644 --- a/io_uring/filetable.c +++ b/io_uring/filetable.c @@ -19,6 +19,9 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx) unsigned long nr = ctx->file_alloc_end; int ret; + if (!table->bitmap) + return -ENFILE; + do { ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint); if (ret != nr) diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index e2bac9f89902..7a43aed8e395 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -794,6 +794,7 @@ void __io_sqe_files_unregister(struct io_ring_ctx *ctx) } #endif io_free_file_tables(&ctx->file_table); + io_file_table_set_alloc_range(ctx, 0, 0); io_rsrc_data_free(ctx->file_data); ctx->file_data = NULL; ctx->nr_user_files = 0;