GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-27 00:51:35 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

KEYS/DNS: Fix ____call_usermodehelper() to not lose the session keyring

Browse source 
____call_usermodehelper() now erases any credentials set by the
subprocess_inf::init() function.  The problem is that commit
17f60a7da1 ("capabilites: allow the application of capability limits
to usermode helpers") creates and commits new credentials with
prepare_kernel_cred() after the call to the init() function.  This wipes
all keyrings after umh_keys_init() is called.

The best way to deal with this is to put the init() call just prior to
the commit_creds() call, and pass the cred pointer to init().  That
means that umh_keys_init() and suchlike can modify the credentials
_before_ they are published and potentially in use by the rest of the
system.

This prevents request_key() from working as it is prevented from passing
the session keyring it set up with the authorisation token to
/sbin/request-key, and so the latter can't assume the authority to
instantiate the key.  This causes the in-kernel DNS resolver to fail
with ENOKEY unconditionally.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Howells 2011-06-17 11:25:59 +01:00 • committed by Linus Torvalds
parent eb96c92515
commit 879669961b
4 changed files with 15 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

16
kernel/kmod.c
View file

@ -156,12 +156,6 @@ static int ____call_usermodehelper(void *data)
*/
set_user_nice(current, 0);
if (sub_info->init) {
retval = sub_info->init(sub_info);
if (retval)
goto fail;
}
retval = -ENOMEM;
new = prepare_kernel_cred(current);
if (!new)
@ -173,6 +167,14 @@ static int ____call_usermodehelper(void *data)
new->cap_inheritable);
spin_unlock(&umh_sysctl_lock);
if (sub_info->init) {
retval = sub_info->init(sub_info, new);
if (retval) {
abort_creds(new);
goto fail;
}
}
commit_creds(new);
retval = kernel_execve(sub_info->path,
@ -388,7 +390,7 @@ EXPORT_SYMBOL(call_usermodehelper_setup);
* context in which call_usermodehelper_exec is called.
*/
void call_usermodehelper_setfns(struct subprocess_info *info,
int (*init)(struct subprocess_info *info),
int (*init)(struct subprocess_info *info, struct cred *new),
void (*cleanup)(struct subprocess_info *info),
void *data)
{