On Mon, 2020-06-22 at 19:32 -0500, Tyler Hicks wrote:
> Use ima_free_rule() to fix memory leaks of allocated ima_rule_entry
> members, such as .fsname and .keyrings, when deleting a list of rules.
>
> This fixes a memory leak seen when loading by a valid rule that contains
> an additional piece of allocated memory, such as an fsname, followed by
> an invalid rule that triggers a policy load failure:
>
> # echo -e "dont_measure fsname=securityfs\nbad syntax" > \
> /sys/kernel/security/ima/policy
> -bash: echo: write error: Invalid argument
> # echo scan > /sys/kernel/debug/kmemleak
> # cat /sys/kernel/debug/kmemleak
> unreferenced object 0xffff9bab67ca12c0 (size 16):
> comm "tee", pid 684, jiffies 4295212803 (age 252.344s)
> hex dump (first 16 bytes):
> 73 65 63 75 72 69 74 79 66 73 00 6b 6b 6b 6b a5 securityfs.kkkk.
> backtrace:
> [<00000000adc80b1b>] kstrdup+0x2e/0x60
> [<00000000d504cb0d>] ima_parse_add_rule+0x7d4/0x1020
> [<00000000444825ac>] ima_write_policy+0xab/0x1d0
> [<000000002b7f0d6c>] vfs_write+0xde/0x1d0
> [<0000000096feedcf>] ksys_write+0x68/0xe0
> [<0000000052b544a2>] do_syscall_64+0x56/0xa0
> [<000000007ead1ba7>] 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@xxxxxxxxxxxxxxxxxxx>
Thanks! Thinking about it some more. It makes more sense to define
ima_free_rule() here in this patch.
Mimi
> ---
> security/integrity/ima/ima_policy.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 1320333201c6..94ca3b8abb69 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -1431,15 +1431,11 @@ ssize_t ima_parse_add_rule(char *rule)
> void ima_delete_rules(void)
> {
> struct ima_rule_entry *entry, *tmp;
> - int i;
>
> temp_ima_appraise = 0;
> list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
> - for (i = 0; i < MAX_LSM_RULES; i++)
> - kfree(entry->lsm[i].args_p);
> -
> list_del(&entry->list);
> - kfree(entry);
> + ima_free_rule(entry);
> }
> }
>
