xfs_growfs manpage clearly states that the target path must be
an active xfs mountpoint.
Current behavior allows xfs_growfs to proceed if the target path
resides anywhere on a mounted xfs filesystem. This could lead to
unexpected results. Unless the target path is an active xfs
mountpoint, reject it. Create a new fs table lookup function which
matches only active xfs mount points, not any file residing within
those mountpoints.
Signed-off-by: Bill O'Donnell <billodo@xxxxxxxxxx>
---
v4: improve commit message and subject line. Further improvement
of error message for realpath() prior to table lookup in xfs_growfs.
v3: improve error message for realpath failure. Add comments
to better document the differences between fs_table_lookup()
and fs_table_lookup_mount(). Use realpath() in fs_table_lookup_mount()
prior to directory comparison.
v2: in order to properly handle relative pathnames, symlinks,
and bind-mounts, use realpath to establish canonical path name.
This also requires the introduction of a lookup function based
on the target mountpoint.
growfs/xfs_growfs.c | 10 +++++++++-
include/path.h | 1 +
libxcmd/paths.c | 31 +++++++++++++++++++++++++++++++
3 files changed, 41 insertions(+), 1 deletion(-)
diff --git a/growfs/xfs_growfs.c b/growfs/xfs_growfs.c
index a294e14..366176b 100644
--- a/growfs/xfs_growfs.c
+++ b/growfs/xfs_growfs.c
@@ -133,6 +133,7 @@ main(int argc, char **argv)
int spinodes;
int rmapbt_enabled;
int reflink_enabled;
+ char rpath[PATH_MAX];
progname = basename(argv[0]);
setlocale(LC_ALL, "");
@@ -202,7 +203,14 @@ main(int argc, char **argv)
aflag = 1;
fs_table_initialise(0, NULL, 0, NULL);
- fs = fs_table_lookup(argv[optind], FS_MOUNT_POINT);
+
+ if (!realpath(argv[optind], rpath)) {
+ fprintf(stderr, _("%s: path resolution failed for %s: %s\n"),
+ progname, argv[optind], strerror(errno));
+ return 1;
+ }
+
+ fs = fs_table_lookup_mount(rpath);
if (!fs) {
fprintf(stderr, _("%s: %s is not a mounted XFS filesystem\n"),
progname, argv[optind]);
diff --git a/include/path.h b/include/path.h
index d077bac..1d3a902 100644
--- a/include/path.h
+++ b/include/path.h
@@ -56,6 +56,7 @@ extern void fs_table_insert_project_path(char *__dir, uint __projid);
extern fs_path_t *fs_table_lookup(const char *__dir, uint __flags);
+extern fs_path_t *fs_table_lookup_mount(const char *__dir);
typedef struct fs_cursor {
uint count; /* total count of mount entries */
diff --git a/libxcmd/paths.c b/libxcmd/paths.c
index 816acc2..b767e9d 100644
--- a/libxcmd/paths.c
+++ b/libxcmd/paths.c
@@ -65,6 +65,9 @@ fs_device_number(
* Find the FS table entry for the given path. The "flags" argument
* is a mask containing FS_MOUNT_POINT or FS_PROJECT_PATH (or both)
* to indicate the type of table entry sought.
+ * fs_table_lookup() finds the fs table entry for the filesystem hosting
+ * the file represented in the "dir" argument. To compare against actual
+ * mount point entries, use fs_table_lookup_mount() instead.
*/
struct fs_path *
fs_table_lookup(
@@ -86,6 +89,34 @@ fs_table_lookup(
return NULL;
}
+/*
+ * Find the FS table entry describing an actual mount for the given path.
+ * Unlike fs_table_lookup(), fs_table_lookup_mount() compares the "dir"
+ * argument to actual mount point entries in the table. Accordingly, it
+ * will find matches only if the "dir" argument is indeed mounted.
+ */
+struct fs_path *
+fs_table_lookup_mount(
+ const char *dir)
+{
+ uint i;
+ dev_t dev = 0;
+ char rpath[PATH_MAX];
+
+ if (fs_device_number(dir, &dev))
+ return NULL;
+
+ for (i = 0; i < fs_count; i++) {
+ if (fs_table[i].fs_flags != FS_MOUNT_POINT)
+ continue;
+ if (!realpath(fs_table[i].fs_dir, rpath))
+ continue;
+ if (strcmp(rpath, dir) == 0)
+ return &fs_table[i];
+ }
+ return NULL;
+}
+
static int
fs_table_insert(
char *dir,
--
2.9.3
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