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Subject[PATCH] [126/139] ima: fix add LSM rule bug
2.6.35-longterm review patch.  If anyone has any objections, please let me know.

From: Mimi Zohar <>

commit 867c20265459d30a01b021a9c1e81fb4c5832aa9 upstream.

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:
dont_measure fsmagic=0x9fa0
dont_measure fsmagic=0x62656572
dont_measure fsmagic=0x64626720
dont_measure fsmagic=0x01021994
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 <>
Signed-off-by: Andi Kleen <>
Cc: James Morris <>
Acked-by: Serge Hallyn <>
Cc: David Safford <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
Signed-off-by: Greg Kroah-Hartman <>

security/integrity/ima/ima_policy.c | 2 ++
1 file changed, 2 insertions(+)

Index: linux-2.6.35.y/security/integrity/ima/ima_policy.c
--- linux-2.6.35.y.orig/security/integrity/ima/ima_policy.c
+++ linux-2.6.35.y/security/integrity/ima/ima_policy.c
@@ -253,6 +253,8 @@ static int ima_lsm_rule_init(struct ima_
result = security_filter_rule_init(entry->lsm[lsm_rule].type,
Audit_equal, args,
+ if (!entry->lsm[lsm_rule].rule)
+ return -EINVAL;
return result;

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