The directory and Rock Ridge / SUSP walk in iso9660_dir() derives several
lengths directly from attacker-controlled on-disk fields without validating
them. libfsimage is used by pygrub, which parses the filesystem of an
untrusted guest disk image from dom0, so these are reachable across a trust
boundary.
Five related problems are addressed:
* The directory record loop advances by
idr = (char *)idr + idr->length.l
and only stops on length.l == 0. A record whose length is smaller than
the fixed part of the on-disk layout cannot hold its own mandatory
fields, yet the body still reads name_len/extent/size and computes the
System Use area length from it. Require length to cover at least the
fixed record (sizeof(*idr) - sizeof(idr->name)) before entering the body.
This is CVE-2026-42494.
* The System Use area length is computed before the inner loop as
rr_len = idr->length.l - idr->name_len.l
- sizeof(struct iso_directory_record) + sizeof(idr->name);
in unsigned arithmetic. If length.l is smaller than name_len.l plus the
fixed record size, rr_len underflows to a huge value and the whole SUSP
walk runs off the directory buffer. Guard the subtraction and treat such
records as having no System Use area.
This is CVE-2026-42495.
* Inside the loop, each entry is consumed with
rr_len -= rr_ptr.rr->len;
rr_ptr.ptr += rr_ptr.rr->len;
with no lower or upper bound on the entry's own len byte. A len of 0
spins forever; a len greater than the remaining rr_len underflows it and
walks past the buffer. Validate 4 <= len <= rr_len at the top of the
loop and stop on violation: a structurally broken entry stream cannot be
advanced reliably, so continuing is not meaningful.
This is CVE-2026-62423.
* The NM handler subtracted the 5-byte SUSP/NM header from len without a
lower-bound check, underflowing name_len (the original report). The
generic check above only guarantees len >= 4; NM has an extra flags byte,
so keep an NM-specific len >= 5 check.
This is CVE-2026-62424.
* The CE continuation resets rr_ptr/rr_len from ce.offset and ce.size, both
image-controlled, into the fixed single-sector RRCONT_BUF with no bounds
check. Reject a window that does not fit in the buffer.
This is CVE-2026-62425.
This is XSA-497.
Signed-off-by: Syed Abdul Khaliq <abdul@bugqore.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit fd11acab3d)
Remove the need for "fs-*" targets by creating a "common.mk" which
have flags that are common to libfsimage/common/ and the other
libfsimages/*/ directories.
In common.mk, make $(PIC_OBJS) a recursively expanded variable so it
doesn't matter where $(LIB_SRCS-y) is defined, and remove the extra
$(PIC_OBJS) from libfsimage/common/Makefile.
Use a $(TARGETS) variable to list things to be built. And $(TARGETS)
can be use in the clean target in common.mk.
iso9660/:
Remove the explicit dependency between fsys_iso9660.c and
iso9660.h, this is handled automaticaly by the .*.d dependency files,
and iso9660.h already exist.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
`fsimage' is rather general. And we do not expect this library to be
very useful out of tree because of its unstable ABI.
So add the word `xen'. This will avoid naming conflicts with anyone
else's fsimage library.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Running "make uninstall" does not remove all installed files, a
situation which might cause link related issues if xen is re-installed
in a different location.
In order to make uninstall correctly remove the files it is best
the process should be done recursively by mirroring each "install"
target with an "uninstall" who removes the installed files.
An exception to this rule is uninstalling the files produced by
"qemu-xen-dir-remote" and "qemu-xen-traditional-dir", which are external
to the project. These projects do not implement an "uninstall" target so
the files have to be removed manually.
Signed-off-by: Petre Pircalabu <ppircalabu@bitdefender.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
As recommended in http://www.gnu.org/licenses/gpl-howto.en.html.
This is the result of:
$ git grep -El Mass\|Temple\|Franklin | xargs ./fsf.pl
Where fsf.pl is:
#!/usr/bin/perl -w -pi.bak -0777
my $repl = 'If not, see <http://www.gnu.org/licenses/>.';
my $br = qr/(?:\s*\n\s*(?:[\*\#]|\/\/|\.\\" )?\s*|\s+)/;
my $inwt = qr/[Ii]f${br}not,${br}write${br}(?:to${br})?the${br}Free${br}Software${br}Foundation,(?:${br}Inc\.,)?/;
my $mass = qr/675${br}Mass${br}Ave,?${br}Cambridge,?${br}MA${br}02139,?${br}USA,?\.?/;
my $franklin = qr/51${br}Franklin${br}St(?:reet)?(?:,${br}| - )Fifth${br}Floor,?${br}Boston,?${br}MA,?${br}02110-1301,?${br}USA,?\.?/;
my $temple = qr/59${br}Temple${br}Place(?:,${br}| - )Suite${br}330,?${br}Boston,?${br}MA,?${br}021110?-1307,?${br}USA,?\.?/;
s|$inwt$br$mass|$repl|m;
s|$inwt$br$franklin|$repl|m;
s|$inwt$br$temple|$repl|m;
The only remaining mentions of these addresses are in COPYING files which I
haven't touched.
Some of the changed files are imports from elsewhere, however
filtering them out is tricky, I think it is tolerable to have these
files be modified here and then perhaps reverted on the next sync,
since it's only 1-2 lines and obvious what is going on.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
tools/libfsimage/Rules.mk relies on having certain variables set already; if
they're not set, the definitions dont' work right. The result was a bunch
of empty files and pygrub failing with an uninformative error message.
It's likely that this didn't cause anyone problems becasue changing the
Makefiles didn't cause a re-build; building from a fresh repo results in
completely empty filesystem plugin binaries.
Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Move the inclusion of Rules.mk up so that things like CFLAGS get initialized
properly. Currently only zfs appends CFLAGS. If CFLAGS get reset by Rules.mk
the private settings are lost and compilation of zfs support fails.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
Otherwise make can search the path relative to certain standard paths
such as /usr/include (e.g., the line '-include $(XEN_ROOT)/.config' in
Config.mk suffers from this).
Signed-off-by: Keir Fraser <keir@xen.org>
Fixes a number of these errors:
cc1: warnings being treated as errors
fsys_fat.c: In function 'fat_dir':
fsys_fat.c:304: warning: array subscript has type 'char'
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
These ugly casts are needed according to the ISO C spec.
Acked-by: Keir Fraser <keir@xensource.com>
Syed Abdul Khaliq
Anthony PERARD
Ian Jackson
Petre Pircalabu
Ian Campbell
George Dunlap
Olaf Hering
Keir Fraser
Keir Fraser
Keir Fraser
kfraser@localhost.localdomain
john.levon@sun.com