4:12 a.m.
v2:
audit: fix possible null-pointer dereference in audit_filter_rules
audit: return early if the rule has a lower priority
v1:
audit: return early if the rule has a lower priority
Gaosheng Cui (2):
audit: fix possible null-pointer dereference in audit_filter_rules
audit: return early if the rule has a lower priority
kernel/auditsc.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--
2.30.0
4:12 a.m.
New subject: [PATCH -next, v2 1/2] audit: fix possible null-pointer dereference in audit_filter_rules
Fix this possible null-pointer dereference in audit_filter_rules.
If ctx is null, a null-pointer dereference will occur:
case AUDIT_SADDR_FAM:
if (ctx->sockaddr)
...
break;
audit_filter_rules() error: we previously assumed 'ctx' could be null
Reported-by: kernel test robot <lkp(a)intel.com>
Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1(a)huawei.com>
---
kernel/auditsc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4ba3b8573ff4..42d4a4320526 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -647,7 +647,7 @@ static int audit_filter_rules(struct task_struct *tsk,
result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
break;
case AUDIT_SADDR_FAM:
- if (ctx->sockaddr)
+ if (ctx && ctx->sockaddr)
result = audit_comparator(ctx->sockaddr->ss_family,
f->op, f->val);
break;
--
2.30.0
4:12 p.m.
New subject: [PATCH -next, v2 1/2] audit: fix possible null-pointer dereference in audit_filter_rules
On Wed, Oct 13, 2021 at 5:10 AM Gaosheng Cui <cuigaosheng1(a)huawei.com> wrote:
Fix this possible null-pointer dereference in audit_filter_rules.
Thanks for fixing this, just a couple of small comments:
I think you can drop the description text below here, the code snippet
is just a duplicate of the code and the error message is pretty
obvious.
If ctx is null, a null-pointer dereference will occur:
case AUDIT_SADDR_FAM:
if (ctx->sockaddr)
...
break;
audit_filter_rules() error: we previously assumed 'ctx' could be null
Reported-by: kernel test robot <lkp(a)intel.com>
Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1(a)huawei.com>
I would also add a Fixes tag, for example:
Fixes: bf361231c295 ("audit: add saddr_fam filter field")
---
kernel/auditsc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4ba3b8573ff4..42d4a4320526 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -647,7 +647,7 @@ static int audit_filter_rules(struct task_struct *tsk,
result = audit_comparator(audit_loginuid_set(tsk), f->op,
f->val);
break;
case AUDIT_SADDR_FAM:
- if (ctx->sockaddr)
+ if (ctx && ctx->sockaddr)
result =
audit_comparator(ctx->sockaddr->ss_family,
f->op, f->val);
break;
--
2.30.0
--
paul moore
www.paul-moore.com
2:47 a.m.
New subject: [PATCH -next, v2 1/2] audit: fix possible null-pointer dereference in audit_filter_rules
Thanks for your review, and i have droped the redundant commit message
and add a Fixes tag to the patch.
https://patchwork.kernel.org/project/linux-audit/patch/20211016072351.237...
<https://patchwork.kernel.org/project/linux-audit/patch/20211016072351.237...
Gaosheng.
在 2021/10/14 5:12, Paul Moore 写道:
On Wed, Oct 13, 2021 at 5:10 AM Gaosheng Cui
<cuigaosheng1(a)huawei.com> wrote:
> Fix this possible null-pointer dereference in audit_filter_rules.
Thanks for fixing this, just a couple of small comments:
I think you can drop the description text below here, the code snippet
is just a duplicate of the code and the error message is pretty
obvious.
> If ctx is null, a null-pointer dereference will occur:
> case AUDIT_SADDR_FAM:
> if (ctx->sockaddr)
> ...
> break;
>
> audit_filter_rules() error: we previously assumed 'ctx' could be null
>
> Reported-by: kernel test robot <lkp(a)intel.com>
> Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com>
> Signed-off-by: Gaosheng Cui <cuigaosheng1(a)huawei.com>
I would also add a Fixes tag, for example:
Fixes: bf361231c295 ("audit: add saddr_fam filter field")
> ---
> kernel/auditsc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 4ba3b8573ff4..42d4a4320526 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -647,7 +647,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> result = audit_comparator(audit_loginuid_set(tsk), f->op,
f->val);
> break;
> case AUDIT_SADDR_FAM:
> - if (ctx->sockaddr)
> + if (ctx && ctx->sockaddr)
> result =
audit_comparator(ctx->sockaddr->ss_family,
> f->op, f->val);
> break;
> --
> 2.30.0
4:12 a.m.
New subject: [PATCH -next, v2 2/2] audit: return early if the rule has a lower priority
It is not necessary for audit_filter_rules() functions to check
audit fileds of the rule with a lower priority, and if we did,
there might be some unintended effects, such as the ctx->ppid
may be changed unexpectedly, so return early if the rule has
a lower priority.
Signed-off-by: Gaosheng Cui <cuigaosheng1(a)huawei.com>
---
kernel/auditsc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 42d4a4320526..b517947bfa48 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -470,6 +470,9 @@ static int audit_filter_rules(struct task_struct *tsk,
u32 sid;
unsigned int sessionid;
+ if (ctx && rule->prio <= ctx->prio)
+ return 0;
+
cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
for (i = 0; i < rule->field_count; i++) {
@@ -737,8 +740,6 @@ static int audit_filter_rules(struct task_struct *tsk,
}
if (ctx) {
- if (rule->prio <= ctx->prio)
- return 0;
if (rule->filterkey) {
kfree(ctx->filterkey);
ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
--
2.30.0
4:15 p.m.
New subject: [PATCH -next, v2 2/2] audit: return early if the rule has a lower priority
On Wed, Oct 13, 2021 at 5:10 AM Gaosheng Cui <cuigaosheng1(a)huawei.com> wrote:
It is not necessary for audit_filter_rules() functions to check
audit fileds of the rule with a lower priority, and if we did,
there might be some unintended effects, such as the ctx->ppid
may be changed unexpectedly, so return early if the rule has
a lower priority.
Signed-off-by: Gaosheng Cui <cuigaosheng1(a)huawei.com>
---
kernel/auditsc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
Thanks for this patch, it looks reasonable to me but have you done any
testing with this patch? If so, what have you done?
As a FYI, the audit-testsuite project lives here:
* https://github.com/linux-audit/audit-testsuite
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 42d4a4320526..b517947bfa48 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -470,6 +470,9 @@ static int audit_filter_rules(struct task_struct *tsk,
u32 sid;
unsigned int sessionid;
+ if (ctx && rule->prio <= ctx->prio)
+ return 0;
+
cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
for (i = 0; i < rule->field_count; i++) {
@@ -737,8 +740,6 @@ static int audit_filter_rules(struct task_struct *tsk,
}
if (ctx) {
- if (rule->prio <= ctx->prio)
- return 0;
if (rule->filterkey) {
kfree(ctx->filterkey);
ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
--
2.30.0
--
paul moore
www.paul-moore.com
3:02 a.m.
New subject: [PATCH -next, v2 2/2] audit: return early if the rule has a lower priority
I have done some testing with this patch, we have some testsuites to
verify the
function of audit, and i will test it with the audit-testsuite.
Thanks.
Gaosheng
在 2021/10/14 5:15, Paul Moore 写道:
On Wed, Oct 13, 2021 at 5:10 AM Gaosheng Cui
<cuigaosheng1(a)huawei.com> wrote:
> It is not necessary for audit_filter_rules() functions to check
> audit fileds of the rule with a lower priority, and if we did,
> there might be some unintended effects, such as the ctx->ppid
> may be changed unexpectedly, so return early if the rule has
> a lower priority.
>
> Signed-off-by: Gaosheng Cui <cuigaosheng1(a)huawei.com>
> ---
> kernel/auditsc.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
Thanks for this patch, it looks reasonable to me but have you done any
testing with this patch? If so, what have you done?
As a FYI, the audit-testsuite project lives here:
* https://github.com/linux-audit/audit-testsuite
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 42d4a4320526..b517947bfa48 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -470,6 +470,9 @@ static int audit_filter_rules(struct task_struct *tsk,
> u32 sid;
> unsigned int sessionid;
>
> + if (ctx && rule->prio <= ctx->prio)
> + return 0;
> +
> cred = rcu_dereference_check(tsk->cred, tsk == current ||
task_creation);
>
> for (i = 0; i < rule->field_count; i++) {
> @@ -737,8 +740,6 @@ static int audit_filter_rules(struct task_struct *tsk,
> }
>
> if (ctx) {
> - if (rule->prio <= ctx->prio)
> - return 0;
> if (rule->filterkey) {
> kfree(ctx->filterkey);
> ctx->filterkey = kstrdup(rule->filterkey,
GFP_ATOMIC);
> --
> 2.30.0
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