From: Amir Goldstein Date: Thu, 10 Jul 2025 10:08:30 +0000 (+0200) Subject: fuse: do not allow mapping a non-regular backing file X-Git-Tag: v6.17-rc6~26^2~2^2~5 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e9c8da670e749f7dedc53e3af54a87b041918092;p=thirdparty%2Flinux.git fuse: do not allow mapping a non-regular backing file We do not support passthrough operations other than read/write on regular file, so allowing non-regular backing files makes no sense. Fixes: efad7153bf93 ("fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN") Cc: stable@vger.kernel.org Signed-off-by: Amir Goldstein Reviewed-by: Bernd Schubert Signed-off-by: Miklos Szeredi --- diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c index 607ef735ad4ab..eb97ac009e75d 100644 --- a/fs/fuse/passthrough.c +++ b/fs/fuse/passthrough.c @@ -237,6 +237,11 @@ int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map) if (!file) goto out; + /* read/write/splice/mmap passthrough only relevant for regular files */ + res = d_is_dir(file->f_path.dentry) ? -EISDIR : -EINVAL; + if (!d_is_reg(file->f_path.dentry)) + goto out_fput; + backing_sb = file_inode(file)->i_sb; res = -ELOOP; if (backing_sb->s_stack_depth >= fc->max_stack_depth)