* [PATCH] ima: fix off-by-one comparison on template name length
@ 2016-09-20 17:25 Colin King
2016-09-21 19:10 ` Mimi Zohar
0 siblings, 1 reply; 2+ messages in thread
From: Colin King @ 2016-09-20 17:25 UTC (permalink / raw)
To: Mimi Zohar, James Morris, Serge E . Hallyn, linux-ima-devel,
linux-ima-user, linux-security-module
Cc: linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The comparison of dr_v1->template_name_len is off-by-one, so
currently if the length is MAX_TEMPLATE_NAME_LEN we end up
with an out-of-bounds write on template_name when the terminating
zero character is written. Fix the comparison.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
security/integrity/ima/ima_template.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index 24775f3..004723c 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -395,7 +395,7 @@ int ima_restore_measurement_list(loff_t size, void *buf)
hdr_v1->template_name_len =
le32_to_cpu(hdr_v1->template_name_len);
- if ((hdr_v1->template_name_len > MAX_TEMPLATE_NAME_LEN) ||
+ if ((hdr_v1->template_name_len >= MAX_TEMPLATE_NAME_LEN) ||
((bufp + hdr_v1->template_name_len) > bufendp)) {
pr_err("attempting to restore a template name \
that is too long\n");
--
2.9.3
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ima: fix off-by-one comparison on template name length
2016-09-20 17:25 [PATCH] ima: fix off-by-one comparison on template name length Colin King
@ 2016-09-21 19:10 ` Mimi Zohar
0 siblings, 0 replies; 2+ messages in thread
From: Mimi Zohar @ 2016-09-21 19:10 UTC (permalink / raw)
To: Colin King
Cc: James Morris, Serge E . Hallyn, linux-ima-devel, linux-ima-user,
linux-security-module, linux-kernel, Andrew Morton
Hi Colin,
On Tue, 2016-09-20 at 18:25 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The comparison of dr_v1->template_name_len is off-by-one, so
> currently if the length is MAX_TEMPLATE_NAME_LEN we end up
> with an out-of-bounds write on template_name when the terminating
> zero character is written. Fix the comparison.
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
Thank you for the bug report. The patch that introduces this bug is in
the -mm tree. The next posting will include this bug fix.
Thanks!
Mimi
> ---
> security/integrity/ima/ima_template.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
> index 24775f3..004723c 100644
> --- a/security/integrity/ima/ima_template.c
> +++ b/security/integrity/ima/ima_template.c
> @@ -395,7 +395,7 @@ int ima_restore_measurement_list(loff_t size, void *buf)
> hdr_v1->template_name_len =
> le32_to_cpu(hdr_v1->template_name_len);
>
> - if ((hdr_v1->template_name_len > MAX_TEMPLATE_NAME_LEN) ||
> + if ((hdr_v1->template_name_len >= MAX_TEMPLATE_NAME_LEN) ||
> ((bufp + hdr_v1->template_name_len) > bufendp)) {
> pr_err("attempting to restore a template name \
> that is too long\n");
^ permalink raw reply [flat|nested] 2+ messages in thread
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