From nobody Wed May 20 19:35:46 2026 X-Original-To: dev-commits-src-main@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 4gLMGC2BG5z6fHs3 for ; Wed, 20 May 2026 19:35:47 +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 4gLMGC0S6tz3QTL for ; Wed, 20 May 2026 19:35:46 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1779305747; 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=Z8pfblwBi7cLW2Lqd37+7gNFzF8hpUoTFHu0h2SZQOc=; b=Lm8v1EqTpQutANWjOZf7ibuXhVAERbrTwXj+7zb5scYl2e8NKEcRKl2sKX2a9LGlAifmHX J+z2jm2OfPIhHfH+3t/rAUKT+Rqg/sQFxOtlgAHo4mMsOSmlh5tutMG73BqgiH53Ahox7Q JtJ2RTEtd+ZtGUNCvsZ1agwbC9b4CPw4i4uUXzArRHS6CnkJhUFbLWAQPg0MzH/X9r1Kzm 5nJGYlVHNO282dgJgqupAzfHviyTJUKS78GtVgOkA4QMHmCrX7WxB4Xxp/wYehtELAmnIT gCQVVahs7AJo2eXnouPw3n7GL6ZiIf/HxmGEyoi51GIMOYmKyfFWVImr4QE40Q== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1779305747; a=rsa-sha256; cv=none; b=X+MbClhskWTXTQJH2p2waZpLLohONznCiIZOAaRhE8nKpCKv443i79XZXk4ixgA8KXWdWG ShR/Mp6wp4wmpL2kCoMygvQkwgzPrCI6MD46Id7tGHgWBtatESO1T4FotChsXJYQneWZbU Dy7/fh5W37LraNCLTG9hJxfTnTj4VOEdeHCDaZTGZl+43eL0HBTEe57Om8wJAcCAo4m62X KK40KpcNH1H8FblbMFwZYt04EQFAMZ5JlysUaxBF+sYeEObFiUcEivFDmpg4pHPqelXogL 6q52dTgXI0oeJocSZk5lM/3GOG8ksh5EQ0vHfkJTzvmzckV0yDXIkZKad3w46g== 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=1779305747; 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=Z8pfblwBi7cLW2Lqd37+7gNFzF8hpUoTFHu0h2SZQOc=; b=fz85b91ox7inH1maA6UYR8i0Q9h1dbZ5Id0kCbEmyxn4c1sxWFHvxPXn2CaCoEEa2DQDr/ 7YYOzA5hVlSk4ArEZux8BHWsKXD6sVsPNk82dxr8tYNwu2+d+ipNYFaNbO5mPiJRoLBc6f T0BpO2RuCABp2oCUtrRsvY13vSnd3gdvLhTBRjtHEVfV0sOqdbRvaCaJIp41M/k92btqtW JE9G0EulTvU2d3seUS/PSxE5P8CXDhtwVe2XyBwdcMK25tziDvkmKdu7pO4dWecVshH86a 8kY5WrcFQrXlcbhJs+tKfR0qU7k5eMnLKaOWvZBSUZW6lfqRvcFwWTESLA4N0A== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4gLMGB5cpNz1F3Q for ; Wed, 20 May 2026 19:35:46 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 3840e by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Wed, 20 May 2026 19:35:46 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Cc: Alan Somers From: Mark Johnston Subject: git: d91c459a93e5 - main - fusefs: Handle buggy servers' LISTXATTR response List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@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/main X-Git-Reftype: branch X-Git-Commit: d91c459a93e5f70c1d3ad3d504bcf64babed8600 Auto-Submitted: auto-generated Date: Wed, 20 May 2026 19:35:46 +0000 Message-Id: <6a0e0d12.3840e.69e17f68@gitrepo.freebsd.org> The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=d91c459a93e5f70c1d3ad3d504bcf64babed8600 commit d91c459a93e5f70c1d3ad3d504bcf64babed8600 Author: Alan Somers AuthorDate: 2026-05-04 19:35:11 +0000 Commit: Mark Johnston CommitDate: 2026-05-20 19:34:50 +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 8ceb6bb1fb1a..7091296bb453 100644 --- a/sys/fs/fuse/fuse_ipc.h +++ b/sys/fs/fuse/fuse_ipc.h @@ -240,6 +240,7 @@ struct fuse_data { #define FSESS_WARN_INODE_MISMATCH 0x4000000 /* ino != nodeid */ #define FSESS_SETXATTR_EXT 0x8000000 /* extended fuse_setxattr_in */ #define FSESS_AUTO_UNMOUNT 0x10000000 /* perform unmount when server dies */ +#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 | FSESS_AUTO_UNMOUNT) diff --git a/sys/fs/fuse/fuse_vnops.c b/sys/fs/fuse/fuse_vnops.c index dd3cc5f16092..d1badd0700f8 100644 --- a/sys/fs/fuse/fuse_vnops.c +++ b/sys/fs/fuse/fuse_vnops.c @@ -2978,8 +2978,8 @@ 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; @@ -2988,7 +2988,14 @@ 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 - @@ -3044,6 +3051,7 @@ 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; @@ -3124,8 +3132,6 @@ 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; " @@ -3142,7 +3148,7 @@ 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 */