fuse: handle large user and group ID

If the number in "user_id=N" or "group_id=N" mount options was larger than
INT_MAX then fuse returned EINVAL.

Fix this to handle all valid uid/gid values.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org

1 files changed, 16 insertions, 4 deletions

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 7b8fc7d33def..8474028d7848 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -478,6 +478,17 @@ static const match_table_t tokens = {
         {OPT_ERR,                       NULL}
 };
 
+static int fuse_match_uint(substring_t *s, unsigned int *res)
+{
+        int err = -ENOMEM;
+        char *buf = match_strdup(s);
+        if (buf) {
+                err = kstrtouint(buf, 10, res);
+                kfree(buf);
+        }
+        return err;
+}
+
 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
 {
         char *p;
@@ -488,6 +499,7 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
         while ((p = strsep(&opt, ",")) != NULL) {
                 int token;
                 int value;
+                unsigned uv;
                 substring_t args[MAX_OPT_ARGS];
                 if (!*p)
                         continue;
@@ -511,18 +523,18 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
                         break;
 
                 case OPT_USER_ID:
-                        if (match_int(&args[0], &value))
+                        if (fuse_match_uint(&args[0], &uv))
                                 return 0;
-                        d->user_id = make_kuid(current_user_ns(), value);
+                        d->user_id = make_kuid(current_user_ns(), uv);
                         if (!uid_valid(d->user_id))
                                 return 0;
                         d->user_id_present = 1;
                         break;
 
                 case OPT_GROUP_ID:
-                        if (match_int(&args[0], &value))
+                        if (fuse_match_uint(&args[0], &uv))
                                 return 0;
-                        d->group_id = make_kgid(current_user_ns(), value);
+                        d->group_id = make_kgid(current_user_ns(), uv);
                         if (!gid_valid(d->group_id))
                                 return 0;
                         d->group_id_present = 1;