From nobody Wed May 20 19:36:38 2026 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 4gLMHC3k8nz6fJPp for ; Wed, 20 May 2026 19:36:39 +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 "R13" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4gLMHC0Wrkz3Rn8 for ; Wed, 20 May 2026 19:36:39 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1779305799; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=ac//mFIv5+2ycbAfnVTtUVZQ6tiVaBBxgfF1fP5aZ1w=; b=LxCLMVxtdiW7pA9K8wWIztjeqn6LFxmDdnmsWDCZ9l47kLUZftJqVE1dB/g/8dv1qQy5il gzfYTUIg8fhY4LUbWaQZG4QuJwPmdZ4plELU3/py2V306nt7d2iN0NTLZ3hSEjfzRbwZnI f/txhHvVr+upNNOzmzZ/imGUKoshN6hoo4Jipsx+JTMny0zdYC3CneqQP4cgJbgR2duayS /UkWff1TV0lArqMM0rSWhnNWyO6XLaTDn3YMuSrkUfhE0VNbsgD8cxdixDv0Vn1SyAaWGw 9Hx69ygxviwWpva/UN8ExI0pxA2lyybXDQhJOpz9OV2eoxHbSbDA5H2ylo8RXg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1779305799; a=rsa-sha256; cv=none; b=MCwwjiPHdFG3vrGYEVVSeAbFZl7SZiuELIFZSKGt8DERpTpnS0FRBSz6a6qF/7oxQTMgus +sVtOVb20ckB9BiA2pBn8NYnuU0Abrlnt7ooBBjdTq4mQl5ppOhrVRU5iIZvTdr8fBC/RE kM1dXdrt3gchdTID3JqFKzrdH+/YfYM/w9eGmS6tHDcJVyXBkbeH27AhKN5DTZ+t0X3kKe cvluwRQa64/Mrzpg808xJsjhx/9ggcRnMfiIjJYNsIlnwiYYXyg6ZtuxfwSph4GssbSMWe hc7hiQguFxxmG1TpVEj2RawZ5uWKP8JIvR9HqT2GccvxUvHO1+gv3M5426dQTA== 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=1779305799; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=ac//mFIv5+2ycbAfnVTtUVZQ6tiVaBBxgfF1fP5aZ1w=; b=QWcMhkU8DZpZRpax4kCs6i8bpB0SC7Mk8K2bcHmiGU9fs1HAbGiOh4c9UORuLuh/v2Touv FhxYDNtsNfCXTkz3eZMcukosRPkZY48KgMF8rdPIQb42sX9jJex0jPwxWMY8OuqnZvUkuM M1O49BLCmjcc9RcyIHg8FrFzGcA541cZ40i3sSlY/sIp/CfxcUkLAoTSc3MvL1pmHhK41C xHIPe7rwvFvhm2MJ4GtgpPGkaMlScUJvGSBEhaX2zVwKq8KGOnlNPhCdAS3iL7lsm6OQ6P pVJyOeKm8D2LjBDGxjTclmurvgBGxxFOKvzFILpqbCibcRX2zDYhYvhrDmhtlA== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4gLMHC00SHz1Dbt for ; Wed, 20 May 2026 19:36:39 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 38b8f by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Wed, 20 May 2026 19:36:38 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Cc: Alan Somers From: Mark Johnston Subject: git: df3f3fa82775 - stable/15 - fusefs: Handle buggy servers' LISTXATTR response 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 List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list 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/15 X-Git-Reftype: branch X-Git-Commit: df3f3fa82775ad9dc2189df24da0f1dbf5f096cd Auto-Submitted: auto-generated Date: Wed, 20 May 2026 19:36:38 +0000 Message-Id: <6a0e0d46.38b8f.6a2b87eb@gitrepo.freebsd.org> The branch stable/15 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=df3f3fa82775ad9dc2189df24da0f1dbf5f096cd commit df3f3fa82775ad9dc2189df24da0f1dbf5f096cd Author: Alan Somers AuthorDate: 2026-05-04 19:35:11 +0000 Commit: Mark Johnston CommitDate: 2026-05-20 19:36:00 +0000 fusefs: Handle buggy servers' LISTXATTR response The fuse protocol requires server to respond to LISTXATTR with a NUL-terminated string. If they don't, report an error rather than attempt to scan through uninitialized memory for a NUL. Approved by: so Security: FreeBSD-SA-26:20.fusefs Security: CVE-2026-45252 admbugs: 1039 Reported by: Joshua Rogers Sponsored by: ConnectWise --- sys/fs/fuse/fuse_ipc.h | 1 + sys/fs/fuse/fuse_vnops.c | 18 +++++++---- tests/sys/fs/fusefs/xattr.cc | 73 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 86 insertions(+), 6 deletions(-) diff --git a/sys/fs/fuse/fuse_ipc.h b/sys/fs/fuse/fuse_ipc.h index 374d0891617d..69501adf4e64 100644 --- a/sys/fs/fuse/fuse_ipc.h +++ b/sys/fs/fuse/fuse_ipc.h @@ -238,6 +238,7 @@ struct fuse_data { #define FSESS_WARN_READLINK_EMBEDDED_NUL 0x1000000 /* corrupt READLINK output */ #define FSESS_WARN_DOT_LOOKUP 0x2000000 /* Inconsistent . LOOKUP response */ #define FSESS_WARN_INODE_MISMATCH 0x4000000 /* ino != nodeid */ +#define FSESS_WARN_LSEXTATTR_NUL 0x20000000 /* Non nul-terminated xattr list */ #define FSESS_MNTOPTS_MASK ( \ FSESS_DAEMON_CAN_SPY | FSESS_PUSH_SYMLINKS_IN | \ FSESS_DEFAULT_PERMISSIONS | FSESS_INTR) diff --git a/sys/fs/fuse/fuse_vnops.c b/sys/fs/fuse/fuse_vnops.c index 43a0d2de0d1a..1923325bba19 100644 --- a/sys/fs/fuse/fuse_vnops.c +++ b/sys/fs/fuse/fuse_vnops.c @@ -2895,8 +2895,8 @@ out: * bsd_list, bsd_list_len - output list compatible with bsd vfs */ static int -fuse_xattrlist_convert(char *prefix, const char *list, int list_len, - char *bsd_list, int *bsd_list_len) +fuse_xattrlist_convert(struct fuse_data *data, char *prefix, const char *list, + int list_len, char *bsd_list, int *bsd_list_len) { int len, pos, dist_to_next, prefix_len; @@ -2905,7 +2905,14 @@ fuse_xattrlist_convert(char *prefix, const char *list, int list_len, prefix_len = strlen(prefix); while (pos < list_len && list[pos] != '\0') { - dist_to_next = strlen(&list[pos]) + 1; + dist_to_next = strnlen(&list[pos], list_len - pos - 1) + 1; + if (list[pos + dist_to_next - 1] != '\0') { + fuse_warn(data, FSESS_WARN_LSEXTATTR_NUL, + "The FUSE server returned a non nul-terminated " + "LISTXATTR response."); + return (EXTERROR(EIO, + "The FUSE server returned a malformed list")); + } if (bcmp(&list[pos], prefix, prefix_len) == 0 && list[pos + prefix_len] == extattr_namespace_separator) { len = dist_to_next - @@ -2961,6 +2968,7 @@ fuse_vnop_listextattr(struct vop_listextattr_args *ap) struct fuse_listxattr_in *list_xattr_in; struct fuse_listxattr_out *list_xattr_out; struct mount *mp = vnode_mount(vp); + struct fuse_data *data = fuse_get_mpdata(mp); struct thread *td = ap->a_td; struct ucred *cred = ap->a_cred; char *prefix; @@ -3041,8 +3049,6 @@ fuse_vnop_listextattr(struct vop_listextattr_args *ap) linux_list = fdi.answ; /* FUSE doesn't allow the server to return more data than requested */ if (fdi.iosize > linux_list_len) { - struct fuse_data *data = fuse_get_mpdata(mp); - fuse_warn(data, FSESS_WARN_LSEXTATTR_LONG, "server returned " "more extended attribute data than requested; " @@ -3059,7 +3065,7 @@ fuse_vnop_listextattr(struct vop_listextattr_args *ap) * FreeBSD's format before giving it to the user. */ bsd_list = malloc(linux_list_len, M_TEMP, M_WAITOK); - err = fuse_xattrlist_convert(prefix, linux_list, linux_list_len, + err = fuse_xattrlist_convert(data, prefix, linux_list, linux_list_len, bsd_list, &bsd_list_len); if (err != 0) goto out; diff --git a/tests/sys/fs/fusefs/xattr.cc b/tests/sys/fs/fusefs/xattr.cc index afeacd4a249e..6dfda55079eb 100644 --- a/tests/sys/fs/fusefs/xattr.cc +++ b/tests/sys/fs/fusefs/xattr.cc @@ -492,6 +492,79 @@ TEST_F(ListxattrSig, erange_forever) ASSERT_TRUE(WIFSIGNALED(status)); } +/* + * A buggy or malicious server returns a list that isn't nul-terminated. The + * kernel should handle it gracefully. + */ +TEST_F(Listxattr, not_nul_terminated) +{ + uint64_t ino = 42; + int ns = EXTATTR_NAMESPACE_USER; + char *data; + const char expected[4] = {3, 'f', 'o', 'o'}; + const char first[255] = "user.foo\0system.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"; + const uint8_t badlist[9] = {'u', 's', 'e', 'r', '.', 'f', 'o', 'o', 'd'}; + Sequence seq; + + EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH) + .WillRepeatedly(Invoke( + ReturnImmediate([=](auto in __unused, auto& out) { + SET_OUT_HEADER_LEN(out, entry); + out.body.entry.attr.mode = S_IFREG | 0644; + out.body.entry.nodeid = ino; + out.body.entry.attr.nlink = 1; + out.body.entry.attr_valid = UINT64_MAX; + out.body.entry.entry_valid = UINT64_MAX; + }))); + + /* + * On the first LISTXATTRS call, return a big attribute just to fill + * the heap with non-NUL data. + */ + expect_listxattr(ino, 0, + ReturnImmediate([&](auto in __unused, auto& out) { + out.body.listxattr.size = sizeof(first); + SET_OUT_HEADER_LEN(out, listxattr); + }), &seq + ); + expect_listxattr(ino, sizeof(first), + ReturnImmediate([&](auto in __unused, auto& out) { + memcpy((void*)out.body.bytes, first, sizeof(first)); + out.header.len = sizeof(fuse_out_header) + sizeof(first); + }), &seq + ); + /* + * On the second LISTXATTRS call, return a malformed list with no NUL + * termination. The heap might still be full of the data from the + * first call. + */ + expect_listxattr(ino, 0, + ReturnImmediate([&](auto in __unused, auto& out) { + out.body.listxattr.size = sizeof(badlist); + SET_OUT_HEADER_LEN(out, listxattr); + }), &seq + ); + expect_listxattr(ino, sizeof(badlist), + ReturnImmediate([&](auto in __unused, auto& out) { + memset((void*)out.body.bytes, 'x', sizeof(first)); + memcpy((void*)out.body.bytes, badlist, sizeof(badlist)); + out.header.len = sizeof(fuse_out_header) + sizeof(badlist); + }), &seq + ); + + data = new char[1024]; + + ASSERT_EQ(static_cast(sizeof(expected)), + extattr_list_file(FULLPATH, ns, data, sizeof(data))) + << strerror(errno); + /* + * Receiving this malformed list, the kernel should log it to dmesg and + * report an IO error to the caller. + */ + ASSERT_EQ(-1, extattr_list_file(FULLPATH, ns, data, sizeof(data))); + EXPECT_EQ(EIO, errno); +} + /* * Get the size of the list that it would take to list no extended attributes */