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KEYS: Make /proc/keys check to see if a key is possessed before security check

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Make /proc/keys check to see if the calling process possesses each key before
performing the security check.  The possession check can be skipped if the key
doesn't have the possessor-view permission bit set.

This causes the keys a process possesses to show up in /proc/keys, even if they
don't have matching user/group/other view permissions.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
David Howells
2010-06-11 17:31:10 +01:00
committed by James Morris
parent 9156235b34
commit 927942aabb
3 changed files with 66 additions and 23 deletions
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64
security/keys/process_keys.c
View File

@@ -309,22 +309,19 @@ void key_fsgid_changed(struct task_struct *tsk)
/*****************************************************************************/
/*
* search the process keyrings for the first matching key
* search only my process keyrings for the first matching key
* - we use the supplied match function to see if the description (or other
* feature of interest) matches
* - we return -EAGAIN if we didn't find any matching key
* - we return -ENOKEY if we found only negative matching keys
*/
key_ref_t search_process_keyrings(struct key_type *type,
const void *description,
key_match_func_t match,
const struct cred *cred)
key_ref_t search_my_process_keyrings(struct key_type *type,
const void *description,
key_match_func_t match,
const struct cred *cred)
{
struct request_key_auth *rka;
key_ref_t key_ref, ret, err;
might_sleep();
/* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
* searchable, but we failed to find a key or we found a negative key;
* otherwise we want to return a sample error (probably -EACCES) if
@@ -424,6 +421,36 @@ key_ref_t search_process_keyrings(struct key_type *type,
}
}
/* no key - decide on the error we're going to go for */
key_ref = ret ? ret : err;
found:
return key_ref;
}
/*****************************************************************************/
/*
* search the process keyrings for the first matching key
* - we use the supplied match function to see if the description (or other
* feature of interest) matches
* - we return -EAGAIN if we didn't find any matching key
* - we return -ENOKEY if we found only negative matching keys
*/
key_ref_t search_process_keyrings(struct key_type *type,
const void *description,
key_match_func_t match,
const struct cred *cred)
{
struct request_key_auth *rka;
key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
might_sleep();
key_ref = search_my_process_keyrings(type, description, match, cred);
if (!IS_ERR(key_ref))
goto found;
err = key_ref;
/* if this process has an instantiation authorisation key, then we also
* search the keyrings of the process mentioned there
* - we don't permit access to request_key auth keys via this method
@@ -446,24 +473,19 @@ key_ref_t search_process_keyrings(struct key_type *type,
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
ret = key_ref;
} else {
up_read(&cred->request_key_auth->sem);
}
}
/* no key - decide on the error we're going to go for */
key_ref = ret ? ret : err;
if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
key_ref = ERR_PTR(-ENOKEY);
else if (err == ERR_PTR(-EACCES))
key_ref = ret;
else
key_ref = err;
found:
return key_ref;
@@ -474,7 +496,7 @@ found:
/*
* see if the key we're looking at is the target key
*/
static int lookup_user_key_possessed(const struct key *key, const void *target)
int lookup_user_key_possessed(const struct key *key, const void *target)
{
return key == target;