kernel/ima-fix-add-lsm-rule-bug.patch
Chuck Ebbert ce15d645be Security updates
CVE-2010-4346: install_special_mapping skips security_file_mmap check
  CVE-2010-4649: IB/uverbs: Handle large number of entries in poll CQ
  CVE-2011-0006: ima: fix add LSM rule bug
  CVE-2010-4648: orinoco: fix TKIP countermeasure behaviour
  CVE-2010-4650: fuse: verify ioctl retries
2011-01-22 12:25:37 -05:00

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2.1 KiB
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From: Mimi Zohar <zohar@linux.vnet.ibm.com>
Date: Mon, 3 Jan 2011 22:59:10 +0000 (-0800)
Subject: ima: fix add LSM rule bug
X-Git-Tag: v2.6.37~5
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=867c20265459d30a01b021a9c1e81fb4c5832aa9
ima: fix add LSM rule bug
If security_filter_rule_init() doesn't return a rule, then not everything
is as fine as the return code implies.
This bug only occurs when the LSM (eg. SELinux) is disabled at runtime.
Adding an empty LSM rule causes ima_match_rules() to always succeed,
ignoring any remaining rules.
default IMA TCB policy:
# PROC_SUPER_MAGIC
dont_measure fsmagic=0x9fa0
# SYSFS_MAGIC
dont_measure fsmagic=0x62656572
# DEBUGFS_MAGIC
dont_measure fsmagic=0x64626720
# TMPFS_MAGIC
dont_measure fsmagic=0x01021994
# SECURITYFS_MAGIC
dont_measure fsmagic=0x73636673
< LSM specific rule >
dont_measure obj_type=var_log_t
measure func=BPRM_CHECK
measure func=FILE_MMAP mask=MAY_EXEC
measure func=FILE_CHECK mask=MAY_READ uid=0
Thus without the patch, with the boot parameters 'tcb selinux=0', adding
the above 'dont_measure obj_type=var_log_t' rule to the default IMA TCB
measurement policy, would result in nothing being measured. The patch
prevents the default TCB policy from being replaced.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Cc: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: David Safford <safford@watson.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index aef8c0a..d661afb 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -253,6 +253,8 @@ static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry,
result = security_filter_rule_init(entry->lsm[lsm_rule].type,
Audit_equal, args,
&entry->lsm[lsm_rule].rule);
+ if (!entry->lsm[lsm_rule].rule)
+ return -EINVAL;
return result;
}