From 6fb53cf8ff2c4713247df523404d24f466b98f52 Mon Sep 17 00:00:00 2001
From: Dylan Yudaken <dylany@fb.com>
Date: Tue, 12 Apr 2022 09:30:41 -0700
Subject: [PATCH] io_uring: verify resv is 0 in ringfd register/unregister
Git-commit: 6fb53cf8ff2c4713247df523404d24f466b98f52
Patch-mainline: v5.18-rc3
References: bsc#1205205

Only allow resv field to be 0 in struct io_uring_rsrc_update user
arguments.

Fixes: e7a6c00dc77a ("io_uring: add support for registering ring file descriptors")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220412163042.2788062-4-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 fs/io_uring.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e899192ffb77..a84bfec97d0d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10533,6 +10533,11 @@ static int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
 			break;
 		}
 
+		if (reg.resv) {
+			ret = -EINVAL;
+			break;
+		}
+
 		if (reg.offset == -1U) {
 			start = 0;
 			end = IO_RINGFD_REG_MAX;
@@ -10579,7 +10584,7 @@ static int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
 			ret = -EFAULT;
 			break;
 		}
-		if (reg.offset >= IO_RINGFD_REG_MAX) {
+		if (reg.resv || reg.offset >= IO_RINGFD_REG_MAX) {
 			ret = -EINVAL;
 			break;
 		}
-- 
2.35.3