* [PATCH][next] ima: ima_modsig: Fix use-after-free bug in ima_read_modsig
@ 2019-08-11 23:55 Gustavo A. R. Silva
2019-08-28 13:50 ` Mimi Zohar
0 siblings, 1 reply; 3+ messages in thread
From: Gustavo A. R. Silva @ 2019-08-11 23:55 UTC (permalink / raw)
To: Mimi Zohar, Dmitry Kasatkin, James Morris, Serge E. Hallyn,
Thiago Jung Bauermann
Cc: linux-integrity, linux-security-module, linux-kernel,
Gustavo A. R. Silva
hdr is being freed and then dereferenced by accessing hdr->pkcs7_msg
Fix this by copying the value returned by PTR_ERR(hdr->pkcs7_msg) into
automatic variable err for its safe use after freeing hdr.
Addresses-Coverity-ID: 1485813 ("Read from pointer after free")
Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
security/integrity/ima/ima_modsig.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
index c412e31d1714..e681d4326145 100644
--- a/security/integrity/ima/ima_modsig.c
+++ b/security/integrity/ima/ima_modsig.c
@@ -91,8 +91,9 @@ int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
hdr->pkcs7_msg = pkcs7_parse_message(buf + buf_len, sig_len);
if (IS_ERR(hdr->pkcs7_msg)) {
+ int err = PTR_ERR(hdr->pkcs7_msg);
kfree(hdr);
- return PTR_ERR(hdr->pkcs7_msg);
+ return err;
}
memcpy(hdr->raw_pkcs7, buf + buf_len, sig_len);
--
2.22.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH][next] ima: ima_modsig: Fix use-after-free bug in ima_read_modsig
2019-08-11 23:55 [PATCH][next] ima: ima_modsig: Fix use-after-free bug in ima_read_modsig Gustavo A. R. Silva
@ 2019-08-28 13:50 ` Mimi Zohar
2019-08-28 18:55 ` Gustavo A. R. Silva
0 siblings, 1 reply; 3+ messages in thread
From: Mimi Zohar @ 2019-08-28 13:50 UTC (permalink / raw)
To: Gustavo A. R. Silva, Dmitry Kasatkin, James Morris,
Serge E. Hallyn, Thiago Jung Bauermann
Cc: linux-integrity, linux-security-module, linux-kernel
Hi Gustavo,
On Sun, 2019-08-11 at 18:55 -0500, Gustavo A. R. Silva wrote:
> hdr is being freed and then dereferenced by accessing hdr->pkcs7_msg
>
> Fix this by copying the value returned by PTR_ERR(hdr->pkcs7_msg) into
> automatic variable err for its safe use after freeing hdr.
>
> Addresses-Coverity-ID: 1485813 ("Read from pointer after free")
> Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures")
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
This bug was reported Julia and addressed by Thiago on 8/7. If you
would like to add your Review/Tested-by, the patch can be found in the
linux-integrity next-queued-testing branch.
thanks,
Mimi
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH][next] ima: ima_modsig: Fix use-after-free bug in ima_read_modsig
2019-08-28 13:50 ` Mimi Zohar
@ 2019-08-28 18:55 ` Gustavo A. R. Silva
0 siblings, 0 replies; 3+ messages in thread
From: Gustavo A. R. Silva @ 2019-08-28 18:55 UTC (permalink / raw)
To: Mimi Zohar, Dmitry Kasatkin, James Morris, Serge E. Hallyn,
Thiago Jung Bauermann
Cc: linux-integrity, linux-security-module, linux-kernel
On 8/28/19 8:50 AM, Mimi Zohar wrote:
> Hi Gustavo,
>
> On Sun, 2019-08-11 at 18:55 -0500, Gustavo A. R. Silva wrote:
>> hdr is being freed and then dereferenced by accessing hdr->pkcs7_msg
>>
>> Fix this by copying the value returned by PTR_ERR(hdr->pkcs7_msg) into
>> automatic variable err for its safe use after freeing hdr.
>>
>> Addresses-Coverity-ID: 1485813 ("Read from pointer after free")
>> Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>
> This bug was reported Julia and addressed by Thiago on 8/7. If you
> would like to add your Review/Tested-by, the patch can be found in the
> linux-integrity next-queued-testing branch.
>
I'm glad this is fixed now. :)
Yeah, you can add my:
Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Thanks
--
Gustavo
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2019-08-11 23:55 [PATCH][next] ima: ima_modsig: Fix use-after-free bug in ima_read_modsig Gustavo A. R. Silva
2019-08-28 13:50 ` Mimi Zohar
2019-08-28 18:55 ` Gustavo A. R. Silva
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