From nobody Thu Apr 24 13:21:18 2025 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4ZjxSZ6XFcz5tHKk; Thu, 24 Apr 2025 13:21:18 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R11" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4ZjxSZ5M2Nz44v9; Thu, 24 Apr 2025 13:21:18 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1745500878; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=Ypin6pERTgfAm8Ryvq4fxztO+SasL+3e8dMN/hGY7cQ=; b=DEbdERXN2UwBVIqd4a56NG74IO9B+cWHZiPBRy99Q+wQPlpWanGl/r1N48UBL2QFAoWr/o i2fuC+MjDXa68Wvn9BoUJSEhdPBkY9MXJIZrGyS2AxYBErSyYFbYDUr8u3pyNBuAqcUbA1 kOvguUd2pwa05hGsuOEpe7OKddG1oS6iF19ETfO52DDRAOh8juSXJBmrcDK98CIW542eN+ TmX+lWTiBeG/0jsd8zrvYhxTwGitg5MgH9FgwSYB5Eau+6SEMmo0xTe9Cksme+Y3cvjncv Rdqnom5gUGk6mcXV6UZAVnjOGy2q297UTnx4s1gE4WPwZs/RWWCzc/wlApwoYA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1745500878; a=rsa-sha256; cv=none; b=WMPwsAdT+PVvhDJFC3j/fXA2X1br+pZDPQ2N5iLQMOIH0UdH8y9iZavDnQXxRLFp2F+Xdl XbjAiagYsp2P2P+p9xx+qdgxZLRj8ZefvRMFMZjHEYCfNdSE1aVtx07WCiNbKBiKVnovRd aHH333ni5hJyahnw0c2sUm6eIUeeRjdXluW5Vvtekl9prrp31l1vr/e4MnKG45js8otGlS NBwYw5Wv6ER2VSFDDs1xy0IKsOCA3lR0H9zt+yUrgVDvok5rWmSBMgxQRAjsnOFaOn7djL EW/M5HBBn2L5ESY4ht6HN8LbasMnOCTO+5HkKPg9Kpd6X4Ik/X+AxqE0zH+jRQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1745500878; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=Ypin6pERTgfAm8Ryvq4fxztO+SasL+3e8dMN/hGY7cQ=; b=T5h3V+deSTn3Jz8UfRDvBhmimyrlC45AMkVxn52KEyzzCU3oMt25MC3i0Pi+AKnWgf2OWo 8RKuXfu9qL/J7jIlO5yHLJo2444wLwCfekKeyUa6iWPSL4s7W8K5J08jA5sJi+FBnvTQZ9 rQN9tDLdmA9fCQzkveKOglsiSX95fTkZTXoyr0tkk4rN1EpNkc/mVsyNxR57S5gsZM8RWo 84dwCSxEmz+TbJ/9AGCFYRgg34IWSpnGJYxflrxSvqPr523kEkshdkbB3HfYV/5KgCFPIg T6rMZ/kBk/5mu/E0FsQUAnVG+3x34FjRS1sQ0Z8y04EzOJvx5V47uNPWkw0r1g== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4ZjxSZ4yJZzrjx; Thu, 24 Apr 2025 13:21:18 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 53ODLI0M038231; Thu, 24 Apr 2025 13:21:18 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 53ODLI1Z038228; Thu, 24 Apr 2025 13:21:18 GMT (envelope-from git) Date: Thu, 24 Apr 2025 13:21:18 GMT Message-Id: <202504241321.53ODLI1Z038228@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 1065a7ebdeb8 - stable/14 - posixshm: Fix range locking in shm_write() List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/stable/14 X-Git-Reftype: branch X-Git-Commit: 1065a7ebdeb8fb16ab6a5112cc4845b66c467eb9 Auto-Submitted: auto-generated The branch stable/14 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=1065a7ebdeb8fb16ab6a5112cc4845b66c467eb9 commit 1065a7ebdeb8fb16ab6a5112cc4845b66c467eb9 Author: Mark Johnston AuthorDate: 2025-04-06 22:51:53 +0000 Commit: Mark Johnston CommitDate: 2025-04-24 13:20:52 +0000 posixshm: Fix range locking in shm_write() There is a somewhat strange case where when writing to a POSIX shm object, the object is not allowed to grow, and the I/O offset+length overflows. In that case we simply truncate the I/O to the object size. Later we write-lock the range [offset, objsize). However, we were not checking whether offset > objsize, in which case we're writing zero bytes but locking an invalid range. Modify the range locking in shm_write() to take this possibility into account. While here, rename a variable to make its purpose a bit more clear, and add an assertion against negative offsets (which is supposed to be enforced by the caller of fo_write for I/O to files that aren't character devices). Reported by: syzkaller Reviewed by: kevans, kib MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D49673 (cherry picked from commit 82d8c609cfb7c6d8a9da8e30efa54240f293359e) --- sys/kern/uipc_shm.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c index e159c802795b..c8d5521c5ab1 100644 --- a/sys/kern/uipc_shm.c +++ b/sys/kern/uipc_shm.c @@ -481,7 +481,10 @@ shm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, struct shmfd *shmfd; void *rl_cookie; int error; - off_t size; + off_t newsize; + + KASSERT((flags & FOF_OFFSET) == 0 || uio->uio_offset >= 0, + ("%s: negative offset", __func__)); shmfd = fp->f_data; #ifdef MAC @@ -503,21 +506,23 @@ shm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, return (EFBIG); } - size = shmfd->shm_size; + newsize = atomic_load_64(&shmfd->shm_size); } else { - size = uio->uio_offset + uio->uio_resid; + newsize = uio->uio_offset + uio->uio_resid; } if ((flags & FOF_OFFSET) == 0) rl_cookie = shm_rangelock_wlock(shmfd, 0, OFF_MAX); else - rl_cookie = shm_rangelock_wlock(shmfd, uio->uio_offset, size); + rl_cookie = shm_rangelock_wlock(shmfd, uio->uio_offset, + MAX(newsize, uio->uio_offset)); if ((shmfd->shm_seals & F_SEAL_WRITE) != 0) { error = EPERM; } else { error = 0; if ((shmfd->shm_flags & SHM_GROW_ON_WRITE) != 0 && - size > shmfd->shm_size) { - error = shm_dotruncate_cookie(shmfd, size, rl_cookie); + newsize > shmfd->shm_size) { + error = shm_dotruncate_cookie(shmfd, newsize, + rl_cookie); } if (error == 0) error = uiomove_object(shmfd->shm_object,