Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B9260376BCD; Sat, 12 Sep 2026 13:23:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789219432; cv=none; b=HPqH1FCE/ggHbVp8lGdhC5ynhKa0u/Pf6tW4lf87Mh/CNFPRbXmKlmMWbwmhTz8M3v6j0A1bwAZ9f4yyhvS9n0Tk67kpA4cO3J8UEEcFDf5gUvEEueDyWAEGBSoQ8B4NVYSKyZxRORH0ZVTLAV+RzEJC9OMpTIOioTgCTY4q1i4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789219432; c=relaxed/simple; bh=n+kixdauVlyJqGyoT/pYUO5l/yUC/ZDqvSoQg5IqW5c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=aTzOgHo7vsuLfn1+rgwQTASVO3bUOQf+IVwX7KdURAVlNTcelyoj9cGbH9YX72/r3WGnoL2aExAcE11OpOVAe38vArrSqwiQvAPbMkQldaT1C9TnaHLiTyh8WflvcIw3YRDBqCZRwILWfQPNlApKFX5qm2HR/z9Ny/fTLm/Qzvs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PzaVUo+Z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PzaVUo+Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74BEB1F000FF; Sat, 12 Sep 2026 13:23:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789219430; bh=MfAT3VTYkrBTEAUg3kLB4H6gyiMP+B+8YbJ/spY5QQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PzaVUo+ZMENtOb1ynue/R4EYe0VlCfmWa5qKnR8/utxESI7l+WlDVbRo8gjD8W3eA McfvBbFREd8oGv5A3e6gTjzeIlkel58c8Sf7LkRN6MmDKGjxA6/lm+emuWYSJP3pvl K9kGJovmBprszT5dZcEiQEd7/2JejQte5ae76bnc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Maciej=20=C5=BBenczykowski?= , Lorenzo Colitti , Yuyang Huang , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.12 1350/1376] bpf: fix BPF_PROG_QUERY OOB write and cgroup backward compat Date: Sat, 12 Sep 2026 09:02:56 +0200 Message-ID: <20260912065637.620183665@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yuyang Huang [ Upstream commit 21c4b99b27f3f85b89256e81b3e997dec0a460d0 ] BPF_PROG_QUERY writes back the 'query.revision' field unconditionally to userspace. If userspace passes a smaller 'bpf_attr' structure (e.g. 40 bytes, which was the layout before the addition of 'query.revision'), the kernel performs an out-of-bounds write. Fix this by propagating the user-provided attribute size 'uattr_size' down to the cgroup query handlers, and conditionally skipping writing the revision field to userspace when the provided buffer size is insufficient. query.revision in bpf_mprog_query is structurally identical to the cgroup case: a late tail field, written unconditionally. But the backward-compat hazard is not the same. The min-historical-size test is per command, and bpf_mprog_query only serves attach types that were born with revision in the struct: - tcx_prog_query -> BPF_TCX_INGRESS/EGRESS - netkit_prog_query -> BPF_NETKIT_PRIMARY/PEER tcx, netkit, the revision field, and bpf_mprog_query itself all landed in the same v6.6 merge window (053c8e1f235d added the mprog query API + revision; tcx in e420bed02507, netkit in 35dfaad7188c). There has never been a tcx/netkit BPF_PROG_QUERY userspace that doesn't know about revision. So for these commands the minimum legitimate struct already covers offset 56-64 — no old binary can be broken here. Contrast with cgroup: BPF_PROG_QUERY on cgroup attach types shipped in 2017; revision write-back was bolted on years later (120933984460). That path has a real population of pre-revision callers. Fixes: 120933984460 ("bpf: Implement mprog API on top of existing cgroup progs") Cc: Maciej Żenczykowski Cc: Lorenzo Colitti Signed-off-by: Yuyang Huang Link: https://lore.kernel.org/r/20260531075600.4058207-2-yuyanghuang@google.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- include/linux/bpf-cgroup.h | 5 +++-- kernel/bpf/cgroup.c | 13 +++++++------ kernel/bpf/syscall.c | 6 +++--- 3 files changed, 13 insertions(+), 11 deletions(-) diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index 26ee360c345fa..a0b5104558124 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -420,7 +420,7 @@ int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype); int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); int cgroup_bpf_prog_query(const union bpf_attr *attr, - union bpf_attr __user *uattr); + union bpf_attr __user *uattr, u32 uattr_size); const struct bpf_func_proto * cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog); @@ -451,7 +451,8 @@ static inline int cgroup_bpf_link_attach(const union bpf_attr *attr, } static inline int cgroup_bpf_prog_query(const union bpf_attr *attr, - union bpf_attr __user *uattr) + union bpf_attr __user *uattr, + u32 uattr_size) { return -EINVAL; } diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index fa2b9f033d84e..b30ea11d93dba 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -1216,7 +1216,7 @@ static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, /* Must be called with cgroup_mutex held to avoid races. */ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, - union bpf_attr __user *uattr) + union bpf_attr __user *uattr, u32 uattr_size) { __u32 __user *prog_attach_flags = u64_to_user_ptr(attr->query.prog_attach_flags); bool effective_query = attr->query.query_flags & BPF_F_QUERY_EFFECTIVE; @@ -1267,7 +1267,8 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, return -EFAULT; if (!effective_query && from_atype == to_atype) revision = cgrp->bpf.revisions[from_atype]; - if (copy_to_user(&uattr->query.revision, &revision, sizeof(revision))) + if (uattr_size >= offsetofend(union bpf_attr, query.revision) && + copy_to_user(&uattr->query.revision, &revision, sizeof(revision))) return -EFAULT; if (attr->query.prog_cnt == 0 || !prog_ids || !total_cnt) /* return early if user requested only program count + flags */ @@ -1320,12 +1321,12 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, } static int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, - union bpf_attr __user *uattr) + union bpf_attr __user *uattr, u32 uattr_size) { int ret; cgroup_lock(); - ret = __cgroup_bpf_query(cgrp, attr, uattr); + ret = __cgroup_bpf_query(cgrp, attr, uattr, uattr_size); cgroup_unlock(); return ret; } @@ -1529,7 +1530,7 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) } int cgroup_bpf_prog_query(const union bpf_attr *attr, - union bpf_attr __user *uattr) + union bpf_attr __user *uattr, u32 uattr_size) { struct cgroup *cgrp; int ret; @@ -1538,7 +1539,7 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, if (IS_ERR(cgrp)) return PTR_ERR(cgrp); - ret = cgroup_bpf_query(cgrp, attr, uattr); + ret = cgroup_bpf_query(cgrp, attr, uattr, uattr_size); cgroup_put(cgrp); return ret; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index ac5500541c7d2..954b299f241b6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4227,7 +4227,7 @@ static int bpf_prog_detach(const union bpf_attr *attr) #define BPF_PROG_QUERY_LAST_FIELD query.revision static int bpf_prog_query(const union bpf_attr *attr, - union bpf_attr __user *uattr) + union bpf_attr __user *uattr, u32 uattr_size) { if (!bpf_net_capable()) return -EPERM; @@ -4266,7 +4266,7 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_CGROUP_GETSOCKOPT: case BPF_CGROUP_SETSOCKOPT: case BPF_LSM_CGROUP: - return cgroup_bpf_prog_query(attr, uattr); + return cgroup_bpf_prog_query(attr, uattr, uattr_size); case BPF_LIRC_MODE2: return lirc_prog_query(attr, uattr); case BPF_FLOW_DISSECTOR: @@ -5720,7 +5720,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size) err = bpf_prog_detach(&attr); break; case BPF_PROG_QUERY: - err = bpf_prog_query(&attr, uattr.user); + err = bpf_prog_query(&attr, uattr.user, size); break; case BPF_PROG_TEST_RUN: err = bpf_prog_test_run(&attr, uattr.user); -- 2.53.0