{"id":2229922,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2229922/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260428214626.13329-1-deller@kernel.org/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260428214626.13329-1-deller@kernel.org>","date":"2026-04-28T21:46:26","name":"linux-user: Allow getsockopt() with NULL optval address","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"7d4c89f76fddf5fc4b59bba6b9d528514b4e948e","submitter":{"id":87076,"url":"http://patchwork.ozlabs.org/api/1.1/people/87076/?format=json","name":"Helge Deller","email":"deller@kernel.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260428214626.13329-1-deller@kernel.org/mbox/","series":[{"id":501938,"url":"http://patchwork.ozlabs.org/api/1.1/series/501938/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=501938","date":"2026-04-28T21:46:26","name":"linux-user: Allow getsockopt() with NULL optval address","version":1,"mbox":"http://patchwork.ozlabs.org/series/501938/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2229922/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2229922/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=MFV8gaR6;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Tue, 28 Apr 2026 17:46:44 -0400","from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58])\n by sea.source.kernel.org (Postfix) with ESMTP id D7F4143AFD;\n Tue, 28 Apr 2026 21:46:32 +0000 (UTC)","by smtp.kernel.org (Postfix) with ESMTPSA id 0D414C2BCAF;\n Tue, 28 Apr 2026 21:46:31 +0000 (UTC)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n s=k20201202; t=1777412792;\n bh=fUbUBNOS+gTd8SfUVwl+U29Q6KEI5N2CjiBhvCbj49U=;\n h=From:To:Cc:Subject:Date:From;\n b=MFV8gaR6hgWnDQI1ScvT+fZ74vt1iNqbp8scngknORj6GilZyl4R7oEGLKeKfHRQn\n 8OiCsVRUBG51894hCqXeSmG8WECZF/KPjUKgrifvabdtJe4S10c2bX3c38qUzdb4n5\n ZeM80sainkrmJAAIEk3egoUnsnSuEQqc/A8g1+A2gY3NW8JBomBgV97lCfVO88qTLn\n 3V2FZZn1jhHT5b7WQDObu5MNJN6j9ZcLlcbcU2EbIQUwnfuDJ+u6dBxJyfCbNWnH85\n lAyVC1MFRDE93C6PvSQIVT5M3LUsLb9XW1Xwa1YzcZ8OpaALor8HN6Xhu86fQ/ReiH\n c9BkQGBorwmHA==","From":"Helge Deller ","To":"qemu-devel@nongnu.org","Cc":"deller@gmx.de","Subject":"[PATCH] linux-user: Allow getsockopt() with NULL optval address","Date":"Tue, 28 Apr 2026 23:46:26 +0200","Message-ID":"<20260428214626.13329-1-deller@kernel.org>","X-Mailer":"git-send-email 2.53.0","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=2600:3c0a:e001:78e:0:1991:8:25;\n envelope-from=deller@kernel.org; helo=sea.source.kernel.org","X-Spam_score_int":"-21","X-Spam_score":"-2.2","X-Spam_bar":"--","X-Spam_report":"(-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.109,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"From: Helge Deller \n\nSome programs test availability of socket options by asking for the\nvalue with an NULL optval address, which currenrly always trigger an\nEFAULT in qemu. Fix it by allowing a NULL address, in the same manner\nas the Linux kernel on physical machines.\n\nResolves: https://gitlab.com/qemu-project/qemu/-/work_items/2390\nSigned-off-by: Helge Deller \n---\n linux-user/syscall.c | 50 +++++++++++++++++++++++++-------------------\n 1 file changed, 28 insertions(+), 22 deletions(-)","diff":"diff --git a/linux-user/syscall.c b/linux-user/syscall.c\nindex 4594909242..d68edb7afd 100644\n--- a/linux-user/syscall.c\n+++ b/linux-user/syscall.c\n@@ -2644,6 +2644,10 @@ get_timeout:\n if (ret < 0) {\n return ret;\n }\n+ /* special case: destination address is NULL, return 0 */\n+ if (optval_addr) {\n+ len = 0;\n+ }\n if (len == sizeof(struct target__kernel_sock_timeval)) {\n if (copy_to_user_timeval64(optval_addr, &tv)) {\n return -TARGET_EFAULT;\n@@ -2844,7 +2848,10 @@ get_timeout:\n }\n if (len > lv)\n len = lv;\n- if (len == 4) {\n+ if (!optval_addr) {\n+ /* writing to NULL does not give error */\n+ len = 0;\n+ } else if (len == 4) {\n if (put_user_u32(val, optval_addr))\n return -TARGET_EFAULT;\n } else {\n@@ -2877,18 +2884,24 @@ get_timeout:\n return -TARGET_EINVAL;\n lv = sizeof(lv);\n ret = get_errno(getsockopt(sockfd, level, optname, &val, &lv));\n+write_ret:\n if (ret < 0)\n return ret;\n- if (len < sizeof(int) && len > 0 && val >= 0 && val < 255) {\n+ if (!optval_addr) {\n+ len = 0;\n+ } else if (len < sizeof(int) && len > 0 && val >= 0 && val < 255) {\n len = 1;\n- if (put_user_u32(len, optlen)\n- || put_user_u8(val, optval_addr))\n+ if (put_user_u8(val, optval_addr)) {\n return -TARGET_EFAULT;\n+ }\n } else {\n if (len > sizeof(int))\n len = sizeof(int);\n- if (put_user_u32(len, optlen)\n- || put_user_u32(val, optval_addr))\n+ if (put_user_u32(val, optval_addr)) {\n+ return -TARGET_EFAULT;\n+ }\n+ }\n+ if (put_user_u32(len, optlen)) {\n return -TARGET_EFAULT;\n }\n break;\n@@ -2939,20 +2952,7 @@ get_timeout:\n return -TARGET_EINVAL;\n lv = sizeof(lv);\n ret = get_errno(getsockopt(sockfd, level, optname, &val, &lv));\n- if (ret < 0)\n- return ret;\n- if (len < sizeof(int) && len > 0 && val >= 0 && val < 255) {\n- len = 1;\n- if (put_user_u32(len, optlen)\n- || put_user_u8(val, optval_addr))\n- return -TARGET_EFAULT;\n- } else {\n- if (len > sizeof(int))\n- len = sizeof(int);\n- if (put_user_u32(len, optlen)\n- || put_user_u32(val, optval_addr))\n- return -TARGET_EFAULT;\n- }\n+ goto write_ret;\n break;\n default:\n ret = -TARGET_ENOPROTOOPT;\n@@ -2986,8 +2986,14 @@ get_timeout:\n if (ret < 0) {\n return ret;\n }\n- if (put_user_u32(lv, optlen)\n- || put_user_u32(val, optval_addr)) {\n+ if (optval_addr) {\n+ if (put_user_u32(val, optval_addr)) {\n+ return -TARGET_EFAULT;\n+ }\n+ } else {\n+ lv = 0;\n+ }\n+ if (put_user_u32(lv, optlen)) {\n return -TARGET_EFAULT;\n }\n break;\n","prefixes":[]}