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Although this might help (or hurt) performance, the main
motivation is to make it easier in future commits
to prevent tarballs from escaping the extraction directory.
* src/common.h: (BADFD): New constant.
(struct fdbase): New type.
* src/create.c (dump_file0): Use parent->fd instead of caching
it into a local, as the latter approach is now awkward.
* src/extract.c (extract_link): Don’t save errno unless needed.
* src/misc.c (safer_rmdir): New arg F.  All callers changed.
(maybe_backup_file): Construct full after_backup_name, now
that find_backup_file_name no longer does that for us.
(chdir_fd): Now static not extern, as other modules now use fdbase.
(fdbase_cache): New static var.
(fdbase_clear): New function.  Call it whenever removing
or renaming directories or symlinks to directories.
(fdbase_opendir): New static function.
(fdbase, fdbase1): New functions.  Call them whenever the
code formerly passed chdir_fd to a syscall.
This commit is contained in:
Paul Eggert
2025-11-15 15:10:48 -08:00
parent 382a47f2fd
commit bdd773d028
9 changed files with 372 additions and 130 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/create.c
+54 -36
View File
@@ -815,12 +815,15 @@ start_header (struct tar_stat_info *st)
break;
case COMMAND_MTIME:
if (!sys_exec_setmtime_script (set_mtime_command,
chdir_fd,
st->orig_file_name,
set_mtime_format,
&mtime))
mtime = st->mtime;
{
struct fdbase f = fdbase (st->orig_file_name);
if (f.fd == BADFD
|| !sys_exec_setmtime_script (set_mtime_command,
f.fd, f.base,
set_mtime_format,
&mtime))
mtime = st->mtime;
}
break;
}
@@ -1338,8 +1341,10 @@ create_archive (void)
{
if (! st.orig_file_name)
{
int fd = openat (chdir_fd, p->name,
open_searchdir_flags);
struct fdbase f = fdbase (p->name);
int fd = (f.fd == BADFD ? -1
: openat (f.fd, f.base,
open_searchdir_flags));
if (fd < 0)
{
file_removed_diag (p->name, !p->parent,
@@ -1539,9 +1544,18 @@ subfile_open (struct tar_stat_info const *dir, char const *file, int flags)
gettext ("");
}
while ((fd = openat (dir ? dir->fd : chdir_fd, file, flags)) < 0
&& open_failure_recover (dir))
continue;
do
{
if (dir)
fd = openat (dir->fd, file, flags);
else
{
struct fdbase f = fdbase (file);
fd = f.fd == BADFD ? -1 : openat (f.fd, f.base, flags);
}
}
while (fd < 0 && open_failure_recover (dir));
return fd;
}
@@ -1569,8 +1583,9 @@ restore_parent_fd (struct tar_stat_info const *st)
if (parentfd < 0)
{
int origfd = openat (chdir_fd, parent->orig_file_name,
open_searchdir_flags);
struct fdbase f = fdbase (parent->orig_file_name);
int origfd = (f.fd == BADFD ? -1
: openat (f.fd, f.base, open_searchdir_flags));
if (0 <= origfd)
{
if (fstat (parentfd, &parentstat) < 0
@@ -1605,7 +1620,6 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
bool is_dir;
struct tar_stat_info const *parent = st->parent;
bool top_level = ! parent;
int parentfd = top_level ? chdir_fd : parent->fd;
void (*diag) (char const *) = 0;
if (interactive_option && !confirm ("add", p))
@@ -1618,12 +1632,15 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
if (!transform_name (&st->file_name, XFORM_REGFILE))
return NULL;
if (parentfd < 0 && ! top_level)
struct fdbase f = (top_level ? fdbase (name)
: (struct fdbase) { .fd = parent->fd, .base = name });
if (!top_level && parent->fd < 0)
{
errno = - parentfd;
errno = - parent->fd;
diag = open_diag;
}
else if (fstatat (parentfd, name, &st->stat, fstatat_flags) < 0)
else if (f.fd == BADFD
|| fstatat (f.fd, f.base, &st->stat, fstatat_flags) < 0)
diag = stat_diag;
else if (file_dumpable_p (&st->stat))
{
@@ -1695,9 +1712,9 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
bool ok;
struct stat st2;
xattrs_acls_get (parentfd, name, st, !is_dir);
xattrs_selinux_get (parentfd, name, st, fd);
xattrs_xattrs_get (parentfd, name, st, fd);
xattrs_acls_get (f.fd, f.base, st, !is_dir);
xattrs_selinux_get (f.fd, f.base, st, fd);
xattrs_xattrs_get (f.fd, f.base, st, fd);
if (is_dir)
{
@@ -1715,7 +1732,8 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
ok = dump_dir (st);
fd = st->fd;
parentfd = top_level ? chdir_fd : parent->fd;
f = (top_level ? fdbase (name)
: (struct fdbase) { .fd = parent->fd, .base = name });
}
else
{
@@ -1756,9 +1774,9 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
}
else if (fd == 0)
{
if (parentfd < 0 && ! top_level)
if (!top_level && parent->fd < 0)
{
errno = - parentfd;
errno = - parent->fd;
ok = false;
}
}
@@ -1809,7 +1827,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
}
else if (atime_preserve_option == replace_atime_preserve
&& timespec_cmp (st->atime, get_stat_atime (&st2)) != 0
&& set_file_atime (fd, parentfd, name, st->atime) < 0)
&& set_file_atime (fd, f.fd, f.base, st->atime) < 0)
utime_error (p);
}
@@ -1821,7 +1839,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
}
else if (S_ISLNK (st->stat.st_mode))
{
st->link_name = areadlinkat_with_size (parentfd, name, st->stat.st_size);
st->link_name = areadlinkat_with_size (f.fd, f.base, st->stat.st_size);
if (!st->link_name)
{
if (errno == ENOMEM)
@@ -1835,8 +1853,8 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
< strlen (st->link_name))
write_long_link (st);
xattrs_selinux_get (parentfd, name, st, 0);
xattrs_xattrs_get (parentfd, name, st, 0);
xattrs_selinux_get (f.fd, f.base, st, 0);
xattrs_xattrs_get (f.fd, f.base, st, 0);
block_ordinal = current_block_ordinal ();
st->stat.st_size = 0; /* force 0 size on symlink */
@@ -1857,23 +1875,23 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
else if (S_ISCHR (st->stat.st_mode))
{
type = CHRTYPE;
xattrs_acls_get (parentfd, name, st, true);
xattrs_selinux_get (parentfd, name, st, 0);
xattrs_xattrs_get (parentfd, name, st, 0);
xattrs_acls_get (f.fd, f.base, st, true);
xattrs_selinux_get (f.fd, f.base, st, 0);
xattrs_xattrs_get (f.fd, f.base, st, 0);
}
else if (S_ISBLK (st->stat.st_mode))
{
type = BLKTYPE;
xattrs_acls_get (parentfd, name, st, true);
xattrs_selinux_get (parentfd, name, st, 0);
xattrs_xattrs_get (parentfd, name, st, 0);
xattrs_acls_get (f.fd, f.base, st, true);
xattrs_selinux_get (f.fd, f.base, st, 0);
xattrs_xattrs_get (f.fd, f.base, st, 0);
}
else if (S_ISFIFO (st->stat.st_mode))
{
type = FIFOTYPE;
xattrs_acls_get (parentfd, name, st, true);
xattrs_selinux_get (parentfd, name, st, 0);
xattrs_xattrs_get (parentfd, name, st, 0);
xattrs_acls_get (f.fd, f.base, st, true);
xattrs_selinux_get (f.fd, f.base, st, 0);
xattrs_xattrs_get (f.fd, f.base, st, 0);
}
else if (S_ISSOCK (st->stat.st_mode))
{