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main: Fix file owner retrieval for chmod

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do_fchmod () and do_chmod () used to call override_mode () directly to
retrieve the owner information, but the usage of override_mode () was
wrong; override_mode () expects struct stat is already populated by
the information provided by the underlying filesystem, but do_fchmod ()
and do_chmod () only zeroed st_uid and st_gid. override_mode () does not
update the owner information when st_mode is not S_IFDIR nor S_IFREG so
this caused chmod to change the file owner to root at random.

Use the logic rpl_stat () employs to file owner retrieval for chmod
functions to ensure they provide the owner information consistent with
rpl_stat ().

Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
This commit is contained in:
Akihiko Odaki 2024-05-29 16:11:00 +09:00
parent a13a9e71dc
commit 136aefd2f6
1 changed files with 25 additions and 28 deletions
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53
main.c
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@ -622,22 +622,32 @@ do_fchownat (struct ovl_data *lo, int dfd, const char *path, uid_t uid, gid_t gi
#define fchownat ERROR #define fchownat ERROR
static int static int
do_fchmod (struct ovl_data *lo, int fd, mode_t mode) do_stat (struct ovl_node *node, int fd, const char *path, struct stat *st)
{
struct ovl_layer *l = node->layer;
if (fd >= 0)
return l->ds->fstat (l, fd, path, STATX_BASIC_STATS, st);
if (path != NULL)
return stat (path, st);
if (node->hidden)
return fstatat (node_dirfd (node), node->path, st, AT_SYMLINK_NOFOLLOW);
return l->ds->statat (l, node->path, st, AT_SYMLINK_NOFOLLOW, STATX_BASIC_STATS);
}
static int
do_fchmod (struct ovl_data *lo, struct ovl_node *node, int fd, mode_t mode)
{ {
if (lo->xattr_permissions) if (lo->xattr_permissions)
{ {
struct ovl_layer *upper = get_upper_layer (lo);
struct stat st; struct stat st;
if (upper == NULL)
{
errno = EROFS;
return -1;
}
st.st_uid = 0; st.st_uid = 0;
st.st_gid = 0; st.st_gid = 0;
if (override_mode (upper, fd, NULL, NULL, &st) < 0 && errno != ENODATA) if (do_stat (node, fd, NULL, &st) < 0)
return -1; return -1;
return write_permission_xattr (lo, fd, NULL, st.st_uid, st.st_gid, mode); return write_permission_xattr (lo, fd, NULL, st.st_uid, st.st_gid, mode);
@ -648,22 +658,15 @@ do_fchmod (struct ovl_data *lo, int fd, mode_t mode)
#define fchmod ERROR #define fchmod ERROR
static int static int
do_chmod (struct ovl_data *lo, const char *path, mode_t mode) do_chmod (struct ovl_data *lo, struct ovl_node *node, const char *path, mode_t mode)
{ {
if (lo->xattr_permissions) if (lo->xattr_permissions)
{ {
struct ovl_layer *upper = get_upper_layer (lo);
struct stat st; struct stat st;
if (upper == NULL)
{
errno = EROFS;
return -1;
}
st.st_uid = 0; st.st_uid = 0;
st.st_gid = 0; st.st_gid = 0;
if (override_mode (upper, -1, path, NULL, &st) < 0 && errno != ENODATA) if (do_stat (node, -1, path, &st) < 0)
return -1; return -1;
return write_permission_xattr (lo, -1, path, st.st_uid, st.st_gid, mode); return write_permission_xattr (lo, -1, path, st.st_uid, st.st_gid, mode);
@ -921,14 +924,8 @@ rpl_stat (fuse_req_t req, struct ovl_node *node, int fd, const char *path, struc
if (st_in) if (st_in)
memcpy (st, st_in, sizeof (*st)); memcpy (st, st_in, sizeof (*st));
else if (fd >= 0)
ret = l->ds->fstat (l, fd, path, STATX_BASIC_STATS, st);
else if (path != NULL)
ret = stat (path, st);
else if (node->hidden)
ret = fstatat (node_dirfd (node), node->path, st, AT_SYMLINK_NOFOLLOW);
else else
ret = l->ds->statat (l, node->path, st, AT_SYMLINK_NOFOLLOW, STATX_BASIC_STATS); ret = do_stat (node, fd, path, st);
if (ret < 0) if (ret < 0)
return ret; return ret;
@ -3823,7 +3820,7 @@ ovl_write_buf (fuse_req_t req, fuse_ino_t ino,
/* if it is a writepage request, make sure to restore the setuid bit. */ /* if it is a writepage request, make sure to restore the setuid bit. */
if (fi->writepage && (inode->mode & (S_ISUID | S_ISGID))) if (fi->writepage && (inode->mode & (S_ISUID | S_ISGID)))
{ {
if (do_fchmod (lo, fi->fh, inode->mode) < 0) if (do_fchmod (lo, inode->node, fi->fh, inode->mode) < 0)
{ {
fuse_reply_err (req, errno); fuse_reply_err (req, errno);
return; return;
@ -4135,9 +4132,9 @@ ovl_setattr (fuse_req_t req, fuse_ino_t ino, struct stat *attr, int to_set, stru
if (to_set & FUSE_SET_ATTR_MODE) if (to_set & FUSE_SET_ATTR_MODE)
{ {
if (fd >= 0) if (fd >= 0)
ret = do_fchmod (lo, fd, attr->st_mode); ret = do_fchmod (lo, node, fd, attr->st_mode);
else else
ret = do_chmod (lo, path, attr->st_mode); ret = do_chmod (lo, node, path, attr->st_mode);
if (ret < 0) if (ret < 0)
{ {
fuse_reply_err (req, errno); fuse_reply_err (req, errno);