[03/12] ima: Free the entire rule when deleting a list of rules
diff mbox series

Message ID 20200623003236.830149-4-tyhicks@linux.microsoft.com
State New
Headers show
Series
  • ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support
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Commit Message

Tyler Hicks June 23, 2020, 12:32 a.m. UTC
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@linux.microsoft.com>
---
 security/integrity/ima/ima_policy.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

Comments

Mimi Zohar June 25, 2020, 9:05 p.m. UTC | #1
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@linux.microsoft.com>

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);
>  	}
>  }
>
Mimi Zohar June 25, 2020, 9:07 p.m. UTC | #2
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@linux.microsoft.com>

Your decision, but you might consider squashing this patch with 3/12.
 Everything all together in one 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);
>  	}
>  }
>
Mimi Zohar June 25, 2020, 9:08 p.m. UTC | #3
On Thu, 2020-06-25 at 17:07 -0400, Mimi Zohar wrote:
> 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@linux.microsoft.com>
> 
> Your decision, but you might consider squashing this patch with 3/12.
>  Everything all together in one patch.

Oops, that was the comment for 4/12.

Mimi

Patch
diff mbox series

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);
 	}
 }