[PATCH] sanitize handling of shared descriptor tables in failing execve()
* unshare_files() can fail; doing it after irreversible actions is wrong
and de_thread() is certainly irreversible.
* since we do it unconditionally anyway, we might as well do it in do_execve()
and save ourselves the PITA in binfmt handlers, etc.
* while we are at it, binfmt_som actually leaked files_struct on failure.
As a side benefit, unshare_files(), put_files_struct() and reset_files_struct()
become unexported.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index b53c7e5..dbf0ac0 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -110,7 +110,6 @@
char *iname_addr = iname;
int retval;
int fd_binary = -1;
- struct files_struct *files = NULL;
retval = -ENOEXEC;
if (!enabled)
@@ -133,21 +132,13 @@
if (fmt->flags & MISC_FMT_OPEN_BINARY) {
- files = current->files;
- retval = unshare_files();
- if (retval < 0)
- goto _ret;
- if (files == current->files) {
- put_files_struct(files);
- files = NULL;
- }
/* if the binary should be opened on behalf of the
* interpreter than keep it open and assign descriptor
* to it */
fd_binary = get_unused_fd();
if (fd_binary < 0) {
retval = fd_binary;
- goto _unshare;
+ goto _ret;
}
fd_install(fd_binary, bprm->file);
@@ -205,10 +196,6 @@
if (retval < 0)
goto _error;
- if (files) {
- put_files_struct(files);
- files = NULL;
- }
_ret:
return retval;
_error:
@@ -216,9 +203,6 @@
sys_close(fd_binary);
bprm->interp_flags = 0;
bprm->interp_data = 0;
-_unshare:
- if (files)
- reset_files_struct(current, files);
goto _ret;
}