From nobody Fri Oct 2 05:30:07 2026 Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C30403D8100 for ; Wed, 5 Aug 2026 05:41:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.41 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785908486; cv=none; b=cfSdgHt3kAx03mavrxnI7vzVFCPV38rywEI+i7F//qgn1Z0sUSGRF8znZRqB616oGpFlyBSzgf935j5FpRPK0DRv7XQBcjLAquqjOFoENLiMQ5uohyEFz04G4xXYoAMfaEKM2npEI8r6Y865Ntn4oqW3CvJOAAL2wLcrFEprItA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785908486; c=relaxed/simple; bh=ywrwsMO35qriJ3f012DB3zk4zuTjPKxkuHP/zwhEiUg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=L4oduP5am0vLoh6/C7hAlT69GQg7gVEH6mtEotQzgqgyJigtAe5HF+pE8KGuyVAjE4vaUFa9Qq91P/EzipQElkaMSm86KVt+SEmxDMhJJelUiT5X2YgqGNrCpi0hsr/ql89dUB8S/Y2iG4Wx01IxlC16fqFP38XvfGTCjEbtZsQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=NPXt1AWC; arc=none smtp.client-ip=209.85.216.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NPXt1AWC" Received: by mail-pj1-f41.google.com with SMTP id 98e67ed59e1d1-38e42560ebcso506892a91.1 for ; Tue, 04 Aug 2026 22:41:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785908480; x=1786513280; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=9DqvMGnPgwJYNDOolmToW7Bu91CUDJtJ7cY9tf14UTg=; b=NPXt1AWCjR4h45h7FZqkmPLLLXq0mDe+PPScH5HAzGdezY3WtXXSAAQKQUdt/jJRWo Wkur+yuOvnAu7QrobAn6+bQaiBCWh1MZAgsxgRZsLFSyAUKk0LsWcXhexzWspNt3wE3S XUcE1bDHjf67M1oKbRObTPuCw3efIWWRG2mZ6fx+0UxKYeyVhFiJhXKHcnnzD27C3DPk pmGkaGaClvhKhCahj9qopKNmvbbPNFcL5PbvcGnMbew34YHRVRk9faCvlBd1o3WmJUKs P/iE1KzCjqZeFElXoi8jzeUWuFXnfmokkEZAAGFuIme6mg93P4ZPkABbRq/a1PI7Vmcf tVTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785908480; x=1786513280; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=9DqvMGnPgwJYNDOolmToW7Bu91CUDJtJ7cY9tf14UTg=; b=sa2qmmdo0mDv0clfqT4tUobehWKDDRHo0uRWBWka2WxsDOjYQLfDmZZe8/21LgTpVs JcoMKznhNm+qa/OEuJyfW1Ftn5u+T7Bb74nPksL7sxLGRAY0XUG8sXVJoqSL4FlKQCJd f/t+Hc6f7gJ0aZ2TcnGzYIF39hTxEcwpHZAyTDMWx7DY7K7hYrBf2s1EdXa3Ydf8XKgC JU7MXLpytSlAshBbVXk3xpOlb6ckQC5jV6iwno3GpIoN+qOyGFK0yMf0O69s4+a9yNdD wRJ9YgTf90eTP12ynwuiptwlgFdde9q0fkcevIsdMPgHoMpFwcIeErj+1Ba16kqnfLaq 1tcQ== X-Forwarded-Encrypted: i=1; AHgh+RpYf31adzakNsfDH/2XOHvwxnixesDf0Nw6lqRP7Xw6nzy48vXEky106km2VqseHuHyHq2tOzlkwPeSrxQ=@vger.kernel.org X-Gm-Message-State: AOJu0YxeBG7c+cHwCCqLvPrYdBKgThEHml6jB+RIoWrhmXP1j4uLKncc ARFDEg41ukHw23z6VLhCgkM5tfi6TPP4hxW3GGvCAfSffWi3S5f76P8I X-Gm-Gg: AR+sD10XHmId/SekOK2BDbgD+DwTGT1Xjpy+BExb6yQOaDbXOfPjJcxfx/q3nGSoliL Wer0TYyQralnaqA+ysqKkegFSWQmzlW6Zpk/zkdXkbMeYr961EpFMJ0kHobEcZWkEAz2Rc/CbQ7 lC/P1KFdN4lA7kgAc8zlZt0UEEYhJU3So/8jPEWfH/BUs5QDC0ImkkHhoamTdhdg7ggSHIqyARl xEZ52b+ox6oLBGvJDQsBrZvCvu46Un3bA99jz5YY4NjnQheStYEvJrALa0+TpDW4MLHXEVEp3Gq 1QyChp9hCgoYuQ93lrm1eDF11169/K6v7C+mUKTnzvbJhori0m+4DEIS7tqZ2aSqMhaaB64xNVr GAyzvp81+GaLkIHR5045v7PgUx7nta1zgrTcqg5evZQCTOzo76itPGZO/oTJ8qaMNt1mc2x34uR m10liaC7xDqywKonQX5sdLcv8HvRmM1R4/P1dbt9rjiAUZ0DxMTvcowwdxMa8lQDchAQ6ll4Ld7 cFLVHvUyR2uF52JKDYJ0qdTEf4vTeTptu9XamvlFr7HRkrmJi60 X-Received: by 2002:a17:90b:224e:b0:38e:9ef9:eb97 with SMTP id 98e67ed59e1d1-3903c5c443dmr3485495a91.16.1785908479682; Tue, 04 Aug 2026 22:41:19 -0700 (PDT) Received: from secrnd-cstp.tailb7f510.ts.net ([125.131.91.97]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3903f5ab5d3sm852195a91.2.2026.08.04.22.41.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Aug 2026 22:41:19 -0700 (PDT) From: Sanghyun Park To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , bpf@vger.kernel.org Cc: Sanghyun Park , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , linux-kernel@vger.kernel.org Subject: [PATCH bpf-next] bpf: Fix stack out-of-bounds write in cgroup link update Date: Wed, 5 Aug 2026 14:28:59 +0900 Message-ID: <20260805052858.2390918-3-sanghyun.park.cnu@gmail.com> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The cgroup link update path checks only the program type, allowing a UDP6 sock_addr program to replace the program on a UDP4 link. Running the replacement writes past the smaller IPv4 context into ipcm_cookie::opt on t= he stack. Require a replacement sock_addr program to have the same expected attach ty= pe as the link before changing link state. Limit the check to sock_addr progra= ms so update policy for other cgroup program types remains unchanged. Fixes: 0c991ebc8c69 ("bpf: Implement bpf_prog replacement for an active bpf= _cgroup_link") Signed-off-by: Sanghyun Park --- kernel/bpf/cgroup.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index d2da5063d8f8..65bf25deac4f 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -1055,6 +1055,10 @@ static int __cgroup_bpf_replace(struct cgroup *cgrp, if (link->link.prog->type !=3D new_prog->type) return -EINVAL; =20 + if (new_prog->type =3D=3D BPF_PROG_TYPE_CGROUP_SOCK_ADDR && + link->link.attach_type !=3D new_prog->expected_attach_type) + return -EINVAL; + hlist_for_each_entry(pl, progs, node) { if (pl->link =3D=3D link) { found =3D true; --=20 2.48.1