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From 22d779d5982dc82d629710d41973ed6545707bd9 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <>
Date: Tue, 28 Jun 2022 13:54:16 +0200
Subject: [PATCH] docs/guestfs-security: document CVE-2022-2211
Short log for the common submodule, commit range
Laszlo Ersek (2):
mlcustomize: factor out pkg install/update/uninstall from guestfs-tools
options: fix buffer overflow in get_keys() [CVE-2022-2211]
Signed-off-by: Laszlo Ersek <>
Message-Id: <>
Reviewed-by: Richard W.M. Jones <>
Cherry picked from commit 99844660b48ed809e37378262c65d63df6ce4a53.
For the cherry pick I only added one submodule commit:
options: fix buffer overflow in get_keys() [CVE-2022-2211]
common | 2 +-
docs/guestfs-security.pod | 28 ++++++++++++++++++++++++++++
2 files changed, 29 insertions(+), 1 deletion(-)
Submodule common be09523d6..1174b443a:
diff --git a/common/options/keys.c b/common/options/keys.c
index 798315c..d27a712 100644
--- a/common/options/keys.c
+++ b/common/options/keys.c
@@ -128,17 +128,23 @@ read_first_line_from_file (const char *filename)
char **
get_keys (struct key_store *ks, const char *device, const char *uuid)
- size_t i, j, len;
+ size_t i, j, nmemb;
char **r;
char *s;
/* We know the returned list must have at least one element and not
* more than ks->nr_keys.
- len = 1;
- if (ks)
- len = MIN (1, ks->nr_keys);
- r = calloc (len+1, sizeof (char *));
+ nmemb = 1;
+ if (ks && ks->nr_keys > nmemb)
+ nmemb = ks->nr_keys;
+ /* make room for the terminating NULL */
+ if (nmemb == (size_t)-1)
+ error (EXIT_FAILURE, 0, _("size_t overflow"));
+ nmemb++;
+ r = calloc (nmemb, sizeof (char *));
if (r == NULL)
error (EXIT_FAILURE, errno, "calloc");
diff --git a/docs/guestfs-security.pod b/docs/guestfs-security.pod
index 9ceef5623..efa35b29d 100644
--- a/docs/guestfs-security.pod
+++ b/docs/guestfs-security.pod
@@ -406,6 +406,34 @@ The libvirt backend is not affected.
The solution is to update qemu to a version containing the fix (see
+=head2 CVE-2022-2211
+The C<get_keys> function in F<libguestfs-common/options/keys.c> collects
+those I<--key> options from the command line into a new array that match
+a particular block device that's being decrypted for inspection. The
+function intends to size the result array such that potentially all
+I<--key> options, plus a terminating C<NULL> element, fit into it. The
+code mistakenly uses the C<MIN> macro instead of C<MAX>, and therefore
+only one element is allocated before the C<NULL> terminator.
+Passing precisely two I<--key ID:...> options on the command line for
+the encrypted block device C<ID> causes C<get_keys> to overwrite the
+terminating C<NULL>, leading to an out-of-bounds read in
+C<decrypt_mountables>, file F<libguestfs-common/options/decrypt.c>.
+Passing more than two I<--key ID:...> options on the command line for
+the encrypted block device C<ID> causes C<get_keys> itself to perform
+out-of-bounds writes. The most common symptom is a crash with C<SIGSEGV>
+later on.
+This issue affects -- broadly speaking -- all libguestfs-based utilities
+that accept I<--key>, namely: C<guestfish>, C<guestmount>, C<virt-cat>,
+C<virt-customize>, C<virt-diff>, C<virt-edit>, C<virt-get-kernel>,
+C<virt-inspector>, C<virt-log>, C<virt-ls>, C<virt-sparsify>,
+C<virt-sysprep>, C<virt-tail>, C<virt-v2v>.
=head1 SEE ALSO