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[PATCH] keys: restrict contents of /proc/keys to Viewable keys

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Restrict /proc/keys such that only those keys to which the current task is
granted View permission are presented.

The documentation is also updated to reflect these changes.

Signed-off-by: Michael LeMay <mdlemay@epoch.ncsc.mil>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Michael LeMay 2006-06-26 00:24:56 -07:00 committed by Linus Torvalds
parent e51f6d3437
commit 06ec7be557
3 changed files with 32 additions and 11 deletions
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16
Documentation/keys.txt
View file

@ -270,9 +270,17 @@ about the status of the key service:
(*) /proc/keys
This lists all the keys on the system, giving information about their
type, description and permissions. The payload of the key is not available
this way:
This lists the keys that are currently viewable by the task reading the
file, giving information about their type, description and permissions.
It is not possible to view the payload of the key this way, though some
information about it may be given.
The only keys included in the list are those that grant View permission to
the reading process whether or not it possesses them. Note that LSM
security checks are still performed, and may further filter out keys that
the current process is not authorised to view.
The contents of the file look like this:
SERIAL FLAGS USAGE EXPY PERM UID GID TYPE DESCRIPTION: SUMMARY
00000001 I----- 39 perm 1f3f0000 0 0 keyring _uid_ses.0: 1/4
@ -300,7 +308,7 @@ about the status of the key service:
(*) /proc/key-users
This file lists the tracking data for each user that has at least one key
on the system. Such data includes quota information and statistics:
on the system. Such data includes quota information and statistics:
[root@andromeda root]# cat /proc/key-users
0: 46 45/45 1/100 13/10000

20
security/Kconfig
View file

@ -22,16 +22,22 @@ config KEYS
If you are unsure as to whether this is required, answer N.
config KEYS_DEBUG_PROC_KEYS
bool "Enable the /proc/keys file by which all keys may be viewed"
bool "Enable the /proc/keys file by which keys may be viewed"
depends on KEYS
help
This option turns on support for the /proc/keys file through which
all the keys on the system can be listed.
This option turns on support for the /proc/keys file - through which
can be listed all the keys on the system that are viewable by the
reading process.
This option is a slight security risk in that it makes it possible
for anyone to see all the keys on the system. Normally the manager
pretends keys that are inaccessible to a process don't exist as far
as that process is concerned.
The only keys included in the list are those that grant View
permission to the reading process whether or not it possesses them.
Note that LSM security checks are still performed, and may further
filter out keys that the current process is not authorised to view.
Only key attributes are listed here; key payloads are not included in
the resulting table.
If you are unsure as to whether this is required, answer N.
config SECURITY
bool "Enable different security models"

7
security/keys/proc.c
View file

@ -137,6 +137,13 @@ static int proc_keys_show(struct seq_file *m, void *v)
struct timespec now;
unsigned long timo;
char xbuf[12];
int rc;
/* check whether the current task is allowed to view the key (assuming
* non-possession) */
rc = key_task_permission(make_key_ref(key, 0), current, KEY_VIEW);
if (rc < 0)
return 0;
now = current_kernel_time();