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[PATCH v2 046/109] virtiofsd: prevent ".." escape in lo_do_readdir()
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PATCH v2 046/109] virtiofsd: prevent ".." escape in lo_do_readdir() |
Date: |
Tue, 21 Jan 2020 12:23:30 +0000 |
From: Stefan Hajnoczi <address@hidden>
Construct a fake dirent for the root directory's ".." entry. This hides
the parent directory from the FUSE client.
Signed-off-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Sergio Lopez <address@hidden>
---
tools/virtiofsd/passthrough_ll.c | 36 +++++++++++++++++++-------------
1 file changed, 22 insertions(+), 14 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 6975417949..7a16e6b4d6 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -1148,19 +1148,25 @@ out_err:
static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
off_t offset, struct fuse_file_info *fi, int plus)
{
+ struct lo_data *lo = lo_data(req);
struct lo_dirp *d;
+ struct lo_inode *dinode;
char *buf = NULL;
char *p;
size_t rem = size;
- int err = ENOMEM;
+ int err = EBADF;
- (void)ino;
+ dinode = lo_inode(req, ino);
+ if (!dinode) {
+ goto error;
+ }
d = lo_dirp(req, fi);
if (!d) {
goto error;
}
+ err = ENOMEM;
buf = calloc(1, size);
if (!buf) {
goto error;
@@ -1191,15 +1197,21 @@ static void lo_do_readdir(fuse_req_t req, fuse_ino_t
ino, size_t size,
}
nextoff = d->entry->d_off;
name = d->entry->d_name;
+
fuse_ino_t entry_ino = 0;
+ struct fuse_entry_param e = (struct fuse_entry_param){
+ .attr.st_ino = d->entry->d_ino,
+ .attr.st_mode = d->entry->d_type << 12,
+ };
+
+ /* Hide root's parent directory */
+ if (dinode == &lo->root && strcmp(name, "..") == 0) {
+ e.attr.st_ino = lo->root.ino;
+ e.attr.st_mode = DT_DIR << 12;
+ }
+
if (plus) {
- struct fuse_entry_param e;
- if (is_dot_or_dotdot(name)) {
- e = (struct fuse_entry_param){
- .attr.st_ino = d->entry->d_ino,
- .attr.st_mode = d->entry->d_type << 12,
- };
- } else {
+ if (!is_dot_or_dotdot(name)) {
err = lo_do_lookup(req, ino, name, &e);
if (err) {
goto error;
@@ -1209,11 +1221,7 @@ static void lo_do_readdir(fuse_req_t req, fuse_ino_t
ino, size_t size,
entsize = fuse_add_direntry_plus(req, p, rem, name, &e, nextoff);
} else {
- struct stat st = {
- .st_ino = d->entry->d_ino,
- .st_mode = d->entry->d_type << 12,
- };
- entsize = fuse_add_direntry(req, p, rem, name, &st, nextoff);
+ entsize = fuse_add_direntry(req, p, rem, name, &e.attr, nextoff);
}
if (entsize > rem) {
if (entry_ino != 0) {
--
2.24.1
- [PATCH v2 036/109] virtiofsd: passthrough_ll: add dirp_map to hide lo_dirp pointers, (continued)
- [PATCH v2 036/109] virtiofsd: passthrough_ll: add dirp_map to hide lo_dirp pointers, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 037/109] virtiofsd: passthrough_ll: add fd_map to hide file descriptors, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 038/109] virtiofsd: passthrough_ll: add fallback for racy ops, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 039/109] virtiofsd: validate path components, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 040/109] virtiofsd: Plumb fuse_bufvec through to do_write_buf, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 041/109] virtiofsd: Pass write iov's all the way through, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 042/109] virtiofsd: add fuse_mbuf_iter API, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 043/109] virtiofsd: validate input buffer sizes in do_write_buf(), Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 045/109] virtiofsd: prevent ".." escape in lo_do_lookup(), Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 044/109] virtiofsd: check input buffer size in fuse_lowlevel.c ops, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 046/109] virtiofsd: prevent ".." escape in lo_do_readdir(),
Dr. David Alan Gilbert (git) <=
- [PATCH v2 047/109] virtiofsd: use /proc/self/fd/ O_PATH file descriptor, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 048/109] virtiofsd: sandbox mount namespace, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 049/109] virtiofsd: move to an empty network namespace, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 051/109] virtiofsd: add seccomp whitelist, Dr. David Alan Gilbert (git), 2020/01/21
- Re: [PATCH v2 051/109] virtiofsd: add seccomp whitelist, Florian Weimer, 2020/01/24