[PATCH for-4.22] tools/libfsimage: Remove the XEN_FSIMAGE_FSDIR environment variable

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

This was reported to the security team, demonstrating that code execution
could be achieved, but without a demonstration of a priviliege boundary being
bypassed.

Still, it's a high risk path with no obvious evidence of having been used even
for debugging, so remove the environment variable and use the build time
$(libdir)/xenfsimage path only.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
CC: Michal Orzel <michal.orzel@xxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Julien Grall <julien@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>

For 4.22.  This was supposed to be posted earlier but fell through the cracks.
Given it's borderline-security aspect, we don't want to delay it any further.
---
 CHANGELOG.md                             | 1 +
 tools/libfsimage/common/fsimage_plugin.c | 5 +----
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ef4e6ae9c459..0a4e5f013cb1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -63,6 +63,7 @@ The format is based on [Keep a 
Changelog](https://keepachangelog.com/en/1.0.0/)
 
  - Removed xenpm tool on non-x86 platforms as it doesn't actually provide
    anything useful outside of x86.
+ - Removed the XEN_FSIMAGE_FSDIR environment variable.
 
 ## 
[4.21.0](https://xenbits.xenproject.org/gitweb/?p=xen.git;a=shortlog;h=RELEASE-4.21.0)
 - 2025-11-19
 
diff --git a/tools/libfsimage/common/fsimage_plugin.c 
b/tools/libfsimage/common/fsimage_plugin.c
index d0cb9e96a654..539dc247356a 100644
--- a/tools/libfsimage/common/fsimage_plugin.c
+++ b/tools/libfsimage/common/fsimage_plugin.c
@@ -121,7 +121,7 @@ static int init_plugin(const char *lib)
 
 int fsi_init(void)
 {
-       const char *fsdir = getenv("XEN_FSIMAGE_FSDIR");
+       const char *fsdir = FSIMAGE_FSDIR;
        struct dirent *dp = NULL;
        DIR *dir = NULL;
        char *tmp = NULL;
@@ -129,9 +129,6 @@ int fsi_init(void)
        int err;
        int ret = -1;
 
-       if (fsdir == NULL)
-               fsdir = FSIMAGE_FSDIR;
-
        if ((name_max = pathconf(fsdir, _PC_NAME_MAX)) == -1)
                goto fail;
 

base-commit: ad9f564a5d840389cbf1b230086e1dd8257d8820
-- 
2.39.5