From 9449d21eeae81d4283e74d7cdccf776e695783f0 Mon Sep 17 00:00:00 2001

From: Laszlo Ersek <lersek@redhat.com>

Date: Wed, 5 Apr 2023 17:08:29 +0200

Subject: [PATCH] detect_kernels: deal with RHEL's kernel-core /

 kernel-modules-core split

In "kernel-5.14.0-269.el9", the "kernel-modules-core" subpackage got split

from the "kernel-core" subpackage. Therefore, a single binary RPM

containing *both* the "/boot/vmlinuz-5.14.0-269.el9.x86_64" file *and* the

"/lib/modules/5.14.0-269.el9.x86_64" directory no longer exists. The file

now belongs to "kernel-core", and the directory to "kernel-modules-core".

As a result, when we investigate the file list of "kernel-core" (based on

"kernel-core" providing "/boot/vmlinuz-5.14.0-269.el9.x86_64"), the first

match against "/lib/modules/" is not the actual module root directory

"/lib/modules/5.14.0-269.el9.x86_64", but the nonsensical

"/lib/modules/5.14.0-269.el9.x86_64/.vmlinuz.hmac" regular file. This

latter file is never a directory, therefore we rule out "kernel-core" as a

kernel package.

We also rule out "kernel-modules-core" (even earlier) because it does not

contain "/boot/vmlinuz-5.14.0-269.el9.x86_64".

Now, the code already deals with the case if the prospective kernel

package *does not provide a match* for the "/lib/modules/" prefix: in that

case, we construct the modpath manually, from said prefix, and the version

number found in "/boot/vmlinuz-<version>". This fallback is good, but it's

unreachable if *there is* a candidate, it's just wrong (i.e., not a

directory).

Perform the "is_dir" check on the candidate modpath earlier, so that we

can fall back to the manual modpath construction if the modpath candidate

exists, but is wrong.

With this, the original "is_dir" check becomes superfluous (duplicated)

*except* when the "Not_found" branch is taken. Therefore, hoist the

original "is_dir" check into that branch.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2175703

Reported-by: Vera Wu <vwu@redhat.com>

Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Tested-by: Vera Wu <vwu@redhat.com>

(ported from libguestfs-common commit 70c10a079a30ff3a84f38596d725a6c5d46e2470)

Message-Id: <20230405150829.171720-3-lersek@redhat.com>

Reviewed-by: Richard W.M. Jones <rjones@redhat.com>

---

 convert/linux_kernels.ml | 24 ++++++++++++++++++------

 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/convert/linux_kernels.ml b/convert/linux_kernels.ml

index 75ab94c4..d0b31643 100644

--- a/convert/linux_kernels.ml

+++ b/convert/linux_kernels.ml

@@ -124,7 +124,7 @@ let detect_kernels (g : G.guestfs) inspect family bootloader =

              let prefix = "/lib/modules/" in

              let prefix_len = String.length prefix in

              try

-               List.find_map (

+               let modpath, version = List.find_map (

                  fun filename ->

                    let filename_len = String.length filename in

                    if filename_len > prefix_len &&

@@ -134,17 +134,29 @@ let detect_kernels (g : G.guestfs) inspect family bootloader =

                      Some (filename, version)

                    ) else

                      None

-               ) files

+               ) files in

+               (* Fall back to the version in the vmlinuz file name not only if

+                * a candidate pathname couldn't be found under /lib/modules/,

+                * but also in case the candidate pathname doesn't reference a

+                * directory. See RHBZ#2175703.

+                *

+                * Note that this "is_dir" check is deliberately kept outside of

+                * the "find_map"'s mapper function above: we want the first

+                * candidate *to be* a directory, and not the first candidate

+                * *that is* a directory.

+                *)

+               if not (g#is_dir ~followsymlinks:true modpath) then

+                 raise Not_found;

+               modpath, version

              with Not_found ->

                let version =

                  String.sub vmlinuz 14 (String.length vmlinuz - 14) in

                let modpath = prefix ^ version in

+               (* Check that the modpath exists. *)

+               if not (g#is_dir ~followsymlinks:true modpath) then

+                 raise Not_found;

                modpath, version in

-           (* Check that the modpath exists. *)

-           if not (g#is_dir ~followsymlinks:true modpath) then

-             raise Not_found;

-

            (* Find the initramfs which corresponds to the kernel.

             * Since the initramfs is built at runtime, and doesn't have

             * to be covered by the RPM file list, this is basically