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ima: extend "mask" policy matching support

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The current "mask" policy option matches files opened as MAY_READ,
MAY_WRITE, MAY_APPEND or MAY_EXEC.  This patch extends the "mask"
option to match files opened containing one of these modes.  For
example, "mask=^MAY_READ" would match files opened read-write.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Dr. Greg Wettstein <gw@idfusion.org>
Cc: stable@vger.kernel.org
This commit is contained in:
Mimi Zohar 2014-11-05 07:53:55 -05:00
parent 139069eff7
commit 4351c294b8
2 changed files with 17 additions and 6 deletions
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3
Documentation/ABI/testing/ima_policy
View File

@ -27,7 +27,8 @@ Description:
base: func:= [BPRM_CHECK][MMAP_CHECK][FILE_CHECK][MODULE_CHECK]
[FIRMWARE_CHECK]
mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
[[^]MAY_EXEC]
fsmagic:= hex value
fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
uid:= decimal value

20
security/integrity/ima/ima_policy.c
View File

@ -27,6 +27,7 @@
#define IMA_UID 0x0008
#define IMA_FOWNER 0x0010
#define IMA_FSUUID 0x0020
#define IMA_INMASK 0x0040
#define IMA_EUID 0x0080
#define UNKNOWN 0
@ -187,6 +188,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
if ((rule->flags & IMA_MASK) &&
(rule->mask != mask && func != POST_SETATTR))
return false;
if ((rule->flags & IMA_INMASK) &&
(!(rule->mask & mask) && func != POST_SETATTR))
return false;
if ((rule->flags & IMA_FSMAGIC)
&& rule->fsmagic != inode->i_sb->s_magic)
return false;
@ -448,6 +452,7 @@ static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
{
struct audit_buffer *ab;
char *from;
char *p;
int result = 0;
@ -538,18 +543,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
if (entry->mask)
result = -EINVAL;
if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
from = args[0].from;
if (*from == '^')
from++;
if ((strcmp(from, "MAY_EXEC")) == 0)
entry->mask = MAY_EXEC;
else if (strcmp(args[0].from, "MAY_WRITE") == 0)
else if (strcmp(from, "MAY_WRITE") == 0)
entry->mask = MAY_WRITE;
else if (strcmp(args[0].from, "MAY_READ") == 0)
else if (strcmp(from, "MAY_READ") == 0)
entry->mask = MAY_READ;
else if (strcmp(args[0].from, "MAY_APPEND") == 0)
else if (strcmp(from, "MAY_APPEND") == 0)
entry->mask = MAY_APPEND;
else
result = -EINVAL;
if (!result)
entry->flags |= IMA_MASK;
entry->flags |= (*args[0].from == '^')
? IMA_INMASK : IMA_MASK;
break;
case Opt_fsmagic:
ima_log_string(ab, "fsmagic", args[0].from);