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From: Tyler Hicks <tyhicks@linux.microsoft.com>
To: Mimi Zohar <zohar@linux.ibm.com>,
	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
	Prakhar Srivastava <prsriva02@gmail.com>,
	linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: [PATCH v3 03/12] ima: Free the entire rule if it fails to parse
Date: Thu,  9 Jul 2020 01:19:02 -0500	[thread overview]
Message-ID: <20200709061911.954326-4-tyhicks@linux.microsoft.com> (raw)
In-Reply-To: <20200709061911.954326-1-tyhicks@linux.microsoft.com>

Use ima_free_rule() to fix memory leaks of allocated ima_rule_entry
members, such as .fsname and .keyrings, when an error is encountered
during rule parsing.

Set the args_p pointer to NULL after freeing it in the error path of
ima_lsm_rule_init() so that it isn't freed twice.

This fixes a memory leak seen when loading an rule that contains an
additional piece of allocated memory, such as an fsname, followed by an
invalid conditional:

 # echo "measure fsname=tmpfs bad=cond" > /sys/kernel/security/ima/policy
 -bash: echo: write error: Invalid argument
 # echo scan > /sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
 unreferenced object 0xffff98e7e4ece6c0 (size 8):
   comm "bash", pid 672, jiffies 4294791843 (age 21.855s)
   hex dump (first 8 bytes):
     74 6d 70 66 73 00 6b a5                          tmpfs.k.
   backtrace:
     [<00000000abab7413>] kstrdup+0x2e/0x60
     [<00000000f11ede32>] ima_parse_add_rule+0x7d4/0x1020
     [<00000000f883dd7a>] ima_write_policy+0xab/0x1d0
     [<00000000b17cf753>] vfs_write+0xde/0x1d0
     [<00000000b8ddfdea>] ksys_write+0x68/0xe0
     [<00000000b8e21e87>] do_syscall_64+0x56/0xa0
     [<0000000089ea7b98>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: f1b08bbcbdaf ("ima: define a new policy condition based on the filesystem name")
Fixes: 2b60c0ecedf8 ("IMA: Read keyrings= option from the IMA policy")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
---

* v3
  - No change
* v2
  - No change

 security/integrity/ima/ima_policy.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index bf00b966e87f..e458cd47c099 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -913,6 +913,7 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 
 		if (ima_rules == &ima_default_rules) {
 			kfree(entry->lsm[lsm_rule].args_p);
+			entry->lsm[lsm_rule].args_p = NULL;
 			result = -EINVAL;
 		} else
 			result = 0;
@@ -1404,7 +1405,7 @@ ssize_t ima_parse_add_rule(char *rule)
 
 	result = ima_parse_rule(p, entry);
 	if (result) {
-		kfree(entry);
+		ima_free_rule(entry);
 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 				    NULL, op, "invalid-policy", result,
 				    audit_info);
-- 
2.25.1


  parent reply	other threads:[~2020-07-09  6:20 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09  6:18 [PATCH v3 00/12] ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support Tyler Hicks
2020-07-09  6:18 ` Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 01/12] ima: Have the LSM free its audit rule Tyler Hicks
2020-07-17 19:20   ` Nayna
2020-07-17 19:24     ` Tyler Hicks
2020-07-19 11:02       ` Mimi Zohar
2020-07-09  6:19 ` [PATCH v3 02/12] ima: Free the entire rule when deleting a list of rules Tyler Hicks
2020-07-09  6:19 ` Tyler Hicks [this message]
2020-07-09  6:19 ` [PATCH v3 04/12] ima: Fail rule parsing when buffer hook functions have an invalid action Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 05/12] ima: Fail rule parsing when the KEXEC_CMDLINE hook is combined with an invalid cond Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 06/12] ima: Fail rule parsing when the KEY_CHECK " Tyler Hicks
2020-07-17 18:56   ` Nayna
2020-07-17 19:18     ` Tyler Hicks
2020-07-17 23:39       ` Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 07/12] ima: Fail rule parsing when appraise_flag=blacklist is unsupportable Tyler Hicks
2020-07-16 18:14   ` Mimi Zohar
2020-07-16 18:20     ` Tyler Hicks
     [not found]   ` <76d2b27b-3b59-1852-046a-b1718c62b167@linux.vnet.ibm.com>
2020-07-17 18:11     ` Tyler Hicks
2020-07-20 17:02       ` Nayna
2020-07-09  6:19 ` [PATCH v3 08/12] ima: Shallow copy the args_p member of ima_rule_entry.lsm elements Tyler Hicks
2020-07-17 15:35   ` Konsta Karsisto
2020-07-17 16:51     ` Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 09/12] ima: Use correct type for " Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 10/12] ima: Move comprehensive rule validation checks out of the token parser Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 11/12] ima: Use the common function to detect LSM conditionals in a rule Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 12/12] ima: Support additional conditionals in the KEXEC_CMDLINE hook function Tyler Hicks
2020-07-09  6:19   ` Tyler Hicks
2020-07-17  4:31 ` [PATCH v3 00/12] ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support Mimi Zohar
2020-07-17  4:34   ` Tyler Hicks
2020-07-17  4:34     ` Tyler Hicks
2020-07-20 21:38 ` Mimi Zohar
2020-07-20 21:38   ` Mimi Zohar

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