From: Karel Zak <kzak@redhat.com>
Date: Wed, 29 Nov 2023 11:37:52 +0000 (+0100)
Subject: libmount: add missing utab options after helper call
X-Git-Tag: v2.40-rc1~136^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=477401f0de;p=thirdparty%2Futil-linux.git

libmount: add missing utab options after helper call

libmount is able to add missing entry to /run/mount/utab after
external /sbin/mouht.<type> helper execution. This is not enough, it's
possible that the helper write proper entry to the utab, but there is
missing some options expected by libmount (usually because the options
are irrelevant fro the helper.

Reproducer:

 Create a stupid mount.foo which writes x-foo=123 to utab:

   # echo -e '#!/bin/bash\n\n/bin/mount -i "$1" "$2" -o x-foo=123' > /sbin/mount.foo
   # chmod +x /sbin/mount.foo

 Run mount which needs to write x-bar=BAR options to utab and executes
 the helper (due to "-t foo", /dev/sdc1 is ext4):

   # mount -t foo /dev/sdc1 /mnt/test -o x-bar=BAR

 old mount:

   # cat /run/mount/utab
   ID=121 SRC=/dev/sdc1 TARGET=/mnt/test ROOT=/ OPTS=x-foo=123

 fixed mount:

   # cat /run/mount/utab
   ID=121 SRC=/dev/sdc1 TARGET=/mnt/test ROOT=/ OPTS=x-foo=123,x-bar=BAR

Fixes: https://github.com/util-linux/util-linux/issues/2554
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libmount/src/tab_update.c b/libmount/src/tab_update.c
index e938ea4647..3a27937040 100644
--- a/libmount/src/tab_update.c
+++ b/libmount/src/tab_update.c
@@ -35,7 +35,9 @@ struct libmnt_update {
 	struct libmnt_fs *fs;
 	char		*filename;
 	unsigned long	mountflags;
-	int		ready;
+
+	unsigned int	ready : 1,
+			missing_options : 1;
 
 	struct libmnt_table *mountinfo;
 };
@@ -173,7 +175,7 @@ int mnt_update_set_fs(struct libmnt_update *upd, unsigned long mountflags,
 
 	mnt_unref_fs(upd->fs);
 	free(upd->target);
-	upd->ready = FALSE;
+	upd->ready = 0;
 	upd->fs = NULL;
 	upd->target = NULL;
 	upd->mountflags = 0;
@@ -206,7 +208,7 @@ int mnt_update_set_fs(struct libmnt_update *upd, unsigned long mountflags,
 	}
 
 	DBG(UPDATE, ul_debugobj(upd, "ready"));
-	upd->ready = TRUE;
+	upd->ready = 1;
 	return 0;
 }
 
@@ -786,6 +788,7 @@ done:
 	return rc;
 }
 
+/* replaces option in the table entry by new options from @udp */
 static int update_modify_options(struct libmnt_update *upd, struct libmnt_lock *lc)
 {
 	struct libmnt_table *tb = NULL;
@@ -826,6 +829,58 @@ static int update_modify_options(struct libmnt_update *upd, struct libmnt_lock *
 	return rc;
 }
 
+/* add user options missing in the table entry by new options from @udp */
+static int update_add_options(struct libmnt_update *upd, struct libmnt_lock *lc)
+{
+	struct libmnt_table *tb = NULL;
+	int rc = 0;
+	struct libmnt_fs *fs;
+
+	assert(upd);
+	assert(upd->fs);
+
+	if (!upd->fs->user_optstr)
+		return 0;
+
+	DBG(UPDATE, ul_debugobj(upd, "%s: add options", upd->filename));
+
+	fs = upd->fs;
+
+	if (lc)
+		rc = mnt_lock_file(lc);
+	if (rc)
+		return -MNT_ERR_LOCK;
+
+	tb = __mnt_new_table_from_file(upd->filename, MNT_FMT_UTAB, 1);
+	if (tb) {
+		struct libmnt_fs *cur = mnt_table_find_target(tb,
+					mnt_fs_get_target(fs),
+					MNT_ITER_BACKWARD);
+		if (cur) {
+			char *u = NULL;
+
+			rc = mnt_optstr_get_missing(cur->user_optstr, upd->fs->user_optstr, &u);
+			if (!rc && u) {
+				DBG(UPDATE, ul_debugobj(upd, " add missing: %s", u));
+				rc = mnt_optstr_append_option(&cur->user_optstr, u, NULL);
+			}
+			if (!rc && u)
+				rc = update_table(upd, tb);
+
+			if (rc == 1)	/* nothing is missing */
+				rc = 0;
+		} else
+			rc = add_file_entry(tb, upd);	/* not found, add new */
+	}
+
+	if (lc)
+		mnt_unlock_file(lc);
+
+	mnt_unref_table(tb);
+	return rc;
+
+}
+
 /**
  * mnt_update_table:
  * @upd: update
@@ -866,10 +921,12 @@ int mnt_update_table(struct libmnt_update *upd, struct libmnt_lock *lc)
 		rc = update_modify_target(upd, lc);	/* move */
 	else if (upd->mountflags & MS_REMOUNT)
 		rc = update_modify_options(upd, lc);	/* remount */
+	else if (upd->fs && upd->missing_options)
+		rc = update_add_options(upd, lc);	/* mount by externel helper */
 	else if (upd->fs)
-		rc = update_add_entry(upd, lc);	/* mount */
+		rc = update_add_entry(upd, lc);		/* mount */
 
-	upd->ready = FALSE;
+	upd->ready = 1;
 	DBG(UPDATE, ul_debugobj(upd, "%s: update tab: done [rc=%d]",
 				upd->filename, rc));
 	if (lc != lc0)
@@ -909,16 +966,26 @@ int mnt_update_already_done(struct libmnt_update *upd, struct libmnt_lock *lc)
 
 	if (upd->fs) {
 		/* mount */
+		struct libmnt_fs *fs;
 		const char *tgt = mnt_fs_get_target(upd->fs);
 		const char *src = mnt_fs_get_bindsrc(upd->fs) ?
 					mnt_fs_get_bindsrc(upd->fs) :
 					mnt_fs_get_source(upd->fs);
 
-		if (mnt_table_find_pair(tb, src, tgt, MNT_ITER_BACKWARD)) {
+		fs = mnt_table_find_pair(tb, src, tgt, MNT_ITER_BACKWARD);
+		if (fs) {
 			DBG(UPDATE, ul_debugobj(upd, "%s: found %s %s",
 						upd->filename, src, tgt));
+
+			/* Check if utab entry (probably writen by /sbin/mount.<type>
+			 * helper) contains all options expected by this update */
+			if (mnt_optstr_get_missing(fs->user_optstr, upd->fs->user_optstr, NULL) == 0) {
+				upd->missing_options = 1;
+				DBG(UPDATE, ul_debugobj(upd, " missing options detected"));
+			}
+		} else
 			rc = 1;
-		}
+
 	} else if (upd->target) {
 		/* umount */
 		if (!mnt_table_find_target(tb, upd->target, MNT_ITER_BACKWARD)) {