When the receiver cannot pin an entry with a held fd and the kernel has no
*xattrat syscalls (pre-6.13 Linux, the BSDs, Solaris, ...), the hardened ACL
path previously skipped the apply with a warning and reported success -- it
silently left the destination ACL stale, so a changed or revoked source ACL
did not propagate yet rsync exited 0.
Per project policy, prefer the documented --acls functionality over refusing it
on platforms that cannot offer the race-safe primitive (Linux 6.13+ takes the
secure xacl_*_at() path, and an operator who needs the guarantee can move
there). The get / default-ACL-delete / set fallbacks now fall through to the
path-based sys_acl_*file() calls -- the long-standing 3.4.x behaviour -- which
restores correct ACL application at the cost of the parent-symlink race that is
unavoidable on those platforms.
Tests: a new acls-unpinnable test asserts a received ACL updates (and removes a
stale grant from) a no-owner-read (0300) destination directory -- validated on
the path-based fallback via a forced-no-xattrat build and on the xattrat path;
its non-Linux / proto-29 skips are added to the per-platform expect-skip lists.
acl-symlink-race PASSES with a note (rather than skipping) where -VV reports no
race-safe primitive, so its skip set stays kernel-independent -- the same
workflow's RSYNC_EXPECT_SKIPPED is shared by no-xattrat and 6.13+ boxes.
fixes a one byte stack overflow when using RSYNC_PROXY with a
malicious proxy.
Reach: only when RSYNC_PROXY is set and a malicious or MITM'd
proxy returns the pathological response. The byte written is
always '\0' and the attacker doesn't choose the offset, so impact
is corruption of one adjacent stack byte and possible later
misbehaviour or crash -- no information disclosure beyond the
existing rprintf of buffer contents.
Reported by Aisle Research via Michal Ruprich
The test was added in dc34990, it turns out that it's flaky. It failed
once on the Debian build infra, cf. [1].
The problem is that the command `rsync -aH '$fromdir/sym' '$todir'`
updates the mod time of `$todir`, so there might be a diff between the
output of `rsync_ls_lR $fromdir` and `rsync_ls_lR $todir`, if ever rsync
runs 1 second (or more) after the directories were created.
To clarify: it's easy to make the test fails 100% of the times with this
change:
```
makepath "$fromdir/sym" "$todir"
+sleep 5
checkit "$RSYNC -aH '$fromdir/sym' '$todir'" "$fromdir" "$todir"
```
With the fix proposed here, we don't use `checkit` anymore, instead we
just run the rsync command, then a simple `diff` to compare the two
directories. This is exactly what the other `-H` test just above does.
In case there's some doubts, `diff` fails if `sym` is missing:
```
$ mkdir -p foo/sym bar
$ diff foo bar || echo KO!
Only in foo: sym
KO!
```
I tested that, after this commit, the test still catches the `-H`
regression in rsync 3.4.0.
Fixes: https://github.com/RsyncProject/rsync/issues/735
[1]: https://buildd.debian.org/status/fetch.php?pkg=rsync&arch=ppc64el&ver=3.4.1%2Bds1-1&stamp=1741147156&raw=0
On an rsync daemon configured with "daemon chroot", the reverse-DNS
lookup of the connecting client was performed *after* the chroot
had been entered. If the chroot did not contain the files glibc
needs for resolution (/etc/resolv.conf, /etc/nsswitch.conf,
/etc/hosts, NSS service modules), the lookup failed and
client_name() returned "UNKNOWN". Hostname-based deny rules
("hosts deny = *.evil.example") therefore could not match, and
an attacker controlling their PTR record could connect from a
hostname the administrator had intended to deny. IP-based ACLs
were unaffected.
Do the reverse DNS lookup before chroot/setuid; client_name()
caches its result, so the post-chroot call uses the cached value
and hostname-based ACLs work even when DNS is unavailable
post-chroot.
Adds testsuite/daemon-chroot-acl.test as end-to-end regression
coverage. The test sets up an empty chroot directory, configures
"hosts deny = <localhost-resolved-name>" with daemon chroot, and
asserts the connection is refused with @ERROR access denied.
Uses unshare --user --map-root-user for non-root CAP_SYS_CHROOT;
skips cleanly on non-Linux or when user namespaces aren't
available.
Reporter: Joshua Rogers (MegaManSec).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add a daemon-refuse-compress test that builds a module configured with
'refuse options = compress' and asserts that:
1. an attempted -z transfer to that module fails with an error
mentioning --compress, and
2. the same transfer without -z still succeeds.
This pins down the documented way to disable all compression on a
daemon, which previously had no automated coverage.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
testsuite/chdir-symlink-race.test runs an actual rsync daemon
(via RSYNC_CONNECT_PROG to avoid the network) configured with
"use chroot = no", plants a symlink at module/subdir -> ../outside,
and runs four flavours of attacker-shaped transfer (single-file
poc_chmod, -r push into the symlinked subdir with --size-only and
without, -r push into the module root). All four must leave the
outside-the-module sentinel file's mode AND content unchanged.
Portability:
- file_mode() helper falls back to BSD stat -f %Lp when GNU
stat -c %a is unavailable (macOS, FreeBSD).
- Pre-saved pristine copy + cmp(1) replaces sha1sum, which
differs across platforms (sha1sum / shasum / sha1).
Tests are kept running as root in the user-namespace re-exec
wrapper used by symlink-race tests so the daemon's setuid path
doesn't drop into the test user's identity (which on Linux
would mean the chmod-escape code path can't trigger because
the test user doesn't have CAP_FOWNER over the outside file).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three related codex audit findings:
Finding 3a: copy_file()'s source open in util1.c used
do_open_nofollow(), which only rejects a final-component
symlink. A parent-component symlink (e.g. --copy-dest=cd where
cd -> /outside) follows freely and reads outside the module.
Route through secure_relative_open() with O_NOFOLLOW.
Finding 3b: generator.c's in-place backup-file create still
used a bare do_open with O_CREAT, leaving a tiny but reachable
parent-symlink window between the secure unlink (already
through do_unlink_at) and the create. Add do_open_at() that
goes through a secure parent dirfd, and route the call site
through it.
Finding 3c: copy_file()'s destination open in
unlink_and_reopen() had the same bare-do_open pattern; route
through do_open_at as well.
Adds testsuite/copy-dest-source-symlink.test and
testsuite/bare-do-open-symlink-race.test as regression coverage
for both attack shapes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add the rest of the path-based syscall wrappers and migrate every
receiver-side caller:
- do_lchown_at, do_rename_at, do_mkdir_at, do_symlink_at,
do_mknod_at, do_link_at, do_unlink_at, do_rmdir_at,
do_utimensat_at, do_stat_at, do_lstat_at
Same shape as do_chmod_at: open each parent under
secure_relative_open(), call the *at() variant against the dirfd,
fall through to the bare path-based syscall in non-daemon /
chrooted / absolute-path / no-parent cases. macOS's
setattrlist-based set_times tier is also routed through the
utimensat_at path on daemon-no-chroot.
Hardenings to secure_relative_open() itself:
- confine basedir resolution under the same kernel mechanism
used for relpath (basedirs from --copy-dest / --link-dest are
sender-controllable in daemon mode)
- reject any '..' component (bare '..', 'foo/..', 'subdir/..')
so the per-component O_NOFOLLOW fallback can't escape
- return the dirfd we built up from the per-component fallback
when the caller passed O_DIRECTORY (otherwise every do_*_at
failed with EINVAL on platforms without RESOLVE_BENEATH)
Adds testsuite/alt-dest-symlink-race.test and
testsuite/secure-relpath-validation.test (with t_secure_relpath
helper) as regression coverage for the new hardenings.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The receiver's chdir(2) into a destination subdirectory followed
attacker-planted symlinks at every path component. Once CWD
escaped the module, every subsequent path-relative syscall (open,
chmod, lchown, ...) inherited the escape -- defeating
secure_relative_open's RESOLVE_BENEATH anchor against AT_FDCWD,
since the anchor itself was now outside the module.
Route change_dir's relative target through secure_relative_open()
and fchdir() to the resulting dirfd in am_daemon && !am_chrooted
mode, so the chdir step itself can no longer follow a parent-
symlink. Same treatment applied to the CD_SKIP_CHDIR /
set_path_only path so it also can't follow attacker symlinks
during path tracking.
Adds testsuite/sender-flist-symlink-leak.test covering the
sender-side flist resolution variant of the same primitive.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
CVE-2026-29518's fix routed the receiver's open() through
secure_relative_open(), but every other path-based syscall the
receiver runs on sender-controllable paths is vulnerable to the
same TOCTOU primitive. This commit closes the chmod variant.
Add do_chmod_at() that opens the parent of fname under
secure_relative_open() and uses fchmodat() against the resulting
dirfd. Gate the secure path on am_daemon && !am_chrooted (the same
gate use_secure_symlinks already uses for the receiver basis-file
open), so non-daemon callers and chrooted daemons keep the original
do_chmod() fast path.
Migrate the receiver-side do_chmod() call sites in delete.c,
generator.c, rsync.c, and xattrs.c.
Adds testsuite/chmod-symlink-race.test (with t_chmod_secure helper)
as regression coverage.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
secure_relative_open() has a kernel-enforced "stay below dirfd" path
on Linux 5.6+ (openat2 RESOLVE_BENEATH) and FreeBSD 13+ (openat
O_RESOLVE_BENEATH). On Solaris, OpenBSD, NetBSD, and Cygwin the code
falls back to the per-component O_NOFOLLOW walk, which by design
rejects every directory symlink in the path -- the very case this
test exercises. Mark the test skipped there rather than have it
fail with a known regression that's tracked separately.
macOS is intentionally not in the skip list: although it does not
have O_RESOLVE_BENEATH either, the test passes there in practice;
investigation of the underlying reason is left as follow-up.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The CVE fix in commit c35e283 made secure_relative_open() walk every
component of relpath with O_NOFOLLOW. That blocks every symlink in the
path, which is stricter than the threat model required: legitimate
directory symlinks within the destination tree (e.g. when using -K /
--copy-dirlinks) are also rejected, breaking delta transfers with
"failed verification -- update discarded". See issue #715.
On Linux 5.6+, openat2(RESOLVE_BENEATH | RESOLVE_NO_MAGICLINKS) gives
us exactly what we want: the kernel rejects any resolution that would
escape the starting directory (via "..", absolute paths, or symlinks
pointing outside dirfd) while still following symlinks that resolve
within it. /proc magic-links are blocked too.
Use openat2 first; fall back to the existing per-component O_NOFOLLOW
walk on ENOSYS (kernel < 5.6). The lexical "../" checks at the head
of the function are kept as defense in depth. The Linux gate is
plain #ifdef __linux__: the runtime ENOSYS fallback covers the only
case that actually matters (header present + old kernel), and any
Linux build environment without linux/openat2.h will fail with a
clear "no such file" error rather than silently disabling the
protection.
Verified manually that openat2(RESOLVE_BENEATH) blocks all four
escape patterns (absolute symlink, ../ symlink, lexical .., absolute
path) while allowing direct and within-tree symlinks. The new
testsuite/symlink-dirlink-basis.test (taken from PR #864 by Samuel
Henrique) exercises the issue #715 regression and passes; full
make check passes 47/47.
Test: testsuite/symlink-dirlink-basis.test (8 scenarios)
Fixes: https://github.com/RsyncProject/rsync/issues/715
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The Solaris xls() function listed every entry in the file's xattr
directory, which on Solaris includes OS-managed SUNWattr_ro and
SUNWattr_rw pseudo-attributes. SUNWattr_rw embeds the file creation
time, so its bytes naturally differ between the source and destination
files, making the xattrs and xattrs-hlink tests fail with diffs that
have nothing to do with rsync.
Rsync's own listxattr wrapper already filters these out
(lib/sysxattrs.c), so the right fix is to filter them in the test
display too. Other platforms are unaffected because each has its own
xls() branch in the case statement.
With the test now actually passing on Solaris, drop the CI hack that
overwrote testsuite/xattrs.test with a skip stub.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The AVX2 get_checksum1_avx2_64() read mul_one before initializing it,
which is undefined behavior. Replace the cmpeq/abs trick with
_mm256_set1_epi8(1) to match the SSSE3 and SSE2 versions.
Add a TEST_SIMD_CHECKSUM1 test mode that verifies all SIMD paths
(SSE2, SSSE3, AVX2, and the full dispatch chain) produce identical
results to the C reference, across multiple buffer sizes with both
aligned and unaligned buffers.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The exclude.test file continues to run local copies (which are a special
kind of "push") while the exclude-lsh.test symlink runs a a "pull" using
the lsh.sh script as the "remote" shell.
* add tests to exercise copy_file
* Extract new function unlink_and_reopen from copy_file
The argument `ofd` to copy_file is always set to -1 unless
`open_tmpfile()` is called at generator.c:909
This change
* removes assignment to a function argument
* renames argument `ofd` to `tmpfilefd` in line with existing uses
* extracts a new function `unlink_and_reopen` which is static to util1.c
* rewrites header comments for copy_file
The Linux fs.protected_regular sysctl setting could cause rsync to fail to write a file in-place with the O_CREAT flag set, so the code now tries an open without O_CREAT when it might help to avoid an EACCES error. A testsuite script is included (and slightly improved by Wayne to ensure that it outputs a SKIP when fs.protected_regular is turned off).
- use `grep -E` and `grep -F` (`egrep` and `fgrep` are non-standard)
- use same hashbang style for all test scripts
- use explicit comparisons in test scripts
- remove redundant ; from test scripts
- make test script not executable, just like all the other scripts
- unify codestyle across all test scripts
- make openssl license exception clearer by having it at the top
- use modern links in COPYING. The text now matches:
https://www.gnu.org/licenses/gpl-3.0.txt
- fix typo
Andrew Tridgell