From mboxrd@z Thu Jan 1 00:00:00 1970 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 F0AF249C4AD for ; Fri, 4 Sep 2026 11:02:30 +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=1788519752; cv=none; b=X2ny9QiIyQf9k2Pu4iApU3ZBIqETr/ojresHhWyE+EjOm2paMLLu6zkRqTgn39rPpdtnWtsgQ0xsCgXJBLFlasR1gB2ICrNP5LXuB950zbfmbXHsQBmJvGu2poVZFAezQGmvA6/WB1brysahXexJrmz9pTvDGmj9Al+i+E1SiwI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788519752; c=relaxed/simple; bh=Cq+fpx/aYNWSA8waJFnoWBwl+vemFvK5noJFhXWsZDY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eQpD8VN8QQpRRlOe2ysoCJsxAWPOT3kCj1lQ2DfVxJobQWODBu3u3wVPkW+UHHpLUzRklzCx1EhoPEG0k8iH+FOmzsuNg+nsihoALPrYz36b42WdO5wcTb7ZHbAb5Jdgfhp8Jj/vOLZexyIE4E2Ip84IK9w/X9Ns+E7IntGvAtk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ECgH2x7B; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ECgH2x7B" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E8FA1F00A3D; Fri, 4 Sep 2026 11:02:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788519750; bh=A/Tbd+SfPZgwQ5DwOeZNhIz0/qTu3TxOJOb2Pa6ScrQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ECgH2x7Bi2pJgv1gaow6SEXAHDMnyIXAfbJaBNquGjjbw0Bdvh+Cdbe5sPe3diI2R ozKuc22HtycZNz7AfpDdEbALXcsQjEXxUOq//jB9GyIfknH1+QgQGDlxiMFOloBW44 O/ZQFDVls4/EghPITAplEbz9u6QwDVJ4Rz3mlRINYLiCNbjhQC7L0v7KK8LPQkJs7d oRXAO3qXoqe02mdy8qXc/ciG18cCbZYdc6YteLWyYm67p6fumaOF8srNMyPTRPG5WY 7qI2qMqThqR2VjVAeIN/5eFNWboEdsUZEFP6Juck7lHZjG6/TyyqaowFYaEZLmzAps aisQZE3iuwL0A== From: Sasha Levin To: stable@vger.kernel.org Cc: Hyunwoo Kim , John Johansen , Sasha Levin Subject: [PATCH 5.15.y] apparmor: fix out-of-bounds write when null terminating a label vec Date: Fri, 4 Sep 2026 07:02:26 -0400 Message-ID: <20260904110227.2843018-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090322-bloated-rerun-fcbb@gregkh> References: <2026090322-bloated-rerun-fcbb@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Hyunwoo Kim [ Upstream commit 9f1e40193eef7f047e6b77cfb4b4cafdecd7a123 ] aa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE is passed. If the components are all distinct no duplicates are dropped, dups is 0 and the terminator goes to vec[n], so the caller has to provide room for n + 1 entries. aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len, gfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but vec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES it uses the local array of LOCAL_VEC_ENTRIES pointers, above that it allocates exactly len pointers. The terminator therefore lands one entry past the end of the local array when len is LOCAL_VEC_ENTRIES, and one entry past the end of the allocation when len is larger. len comes from the number of "//&" separated components in the label name and label_count_strn_entries() does not bound it. An unprivileged task reaches the parse by writing to /proc/self/attr/apparmor/current or through lsm_set_self_attr(2), both of which go through do_setattr(), and the name is parsed before the change_profile permission is checked. The query_label() path behind the securityfs .access file, which is mode 0666, performs no permission check at all. Every component has to resolve to a loaded profile, so a system with policy loaded is required. The other two VEC_FLAG_TERMINATE users work on a label vec that aa_label_alloc() has already sized with "+ 1 for null terminator entry on vec". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing len + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of the local array and into kzalloc(). Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels") Cc: stable@vger.kernel.org Signed-off-by: Hyunwoo Kim Signed-off-by: John Johansen [ replaced unavailable kzalloc_objs() with equivalent kcalloc() allocation ] Signed-off-by: Sasha Levin --- security/apparmor/include/label.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/security/apparmor/include/label.h b/security/apparmor/include/label.h index 55986388dfaeb..a987bd117d88d 100644 --- a/security/apparmor/include/label.h +++ b/security/apparmor/include/label.h @@ -22,7 +22,7 @@ struct aa_ns; #define LOCAL_VEC_ENTRIES 8 #define DEFINE_VEC(T, V) \ - struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES]; \ + struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES + 1]; \ struct aa_ ## T **(V) #define vec_setup(T, V, N, GFP) \ @@ -30,10 +30,10 @@ struct aa_ns; if ((N) <= LOCAL_VEC_ENTRIES) { \ typeof(N) i; \ (V) = (_ ## V ## _localtmp); \ - for (i = 0; i < (N); i++) \ + for (i = 0; i <= (N); i++) \ (V)[i] = NULL; \ } else \ - (V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP)); \ + (V) = kcalloc((N) + 1, sizeof(struct aa_ ## T *), (GFP)); \ (V) ? 0 : -ENOMEM; \ }) -- 2.53.0