* [PATCH] objtool: check: Fix NULL pointer dereference
@ 2020-03-31 0:20 Gustavo A. R. Silva
2020-03-31 22:04 ` Josh Poimboeuf
0 siblings, 1 reply; 3+ messages in thread
From: Gustavo A. R. Silva @ 2020-03-31 0:20 UTC (permalink / raw)
To: Josh Poimboeuf, Peter Zijlstra; +Cc: linux-kernel, Gustavo A. R. Silva
In case func is null, there is a null pointer dereference at 2029:
2029 WARN("%s uses BP as a scratch register",
2030 func->name);
Fix this by null-checking func.
Addresses-Coverity-ID: 1492002 ("Dereference after null check")
Fixes: c705cecc8431 ("objtool: Track original function across branches")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
tools/objtool/check.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e3bb76358148..182cc48fa892 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2025,7 +2025,7 @@ static int validate_return(struct symbol *func, struct instruction *insn, struct
return 1;
}
- if (state->bp_scratch) {
+ if (func && state->bp_scratch) {
WARN("%s uses BP as a scratch register",
func->name);
return 1;
--
2.26.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] objtool: check: Fix NULL pointer dereference
2020-03-31 0:20 [PATCH] objtool: check: Fix NULL pointer dereference Gustavo A. R. Silva
@ 2020-03-31 22:04 ` Josh Poimboeuf
2020-03-31 22:27 ` Gustavo A. R. Silva
0 siblings, 1 reply; 3+ messages in thread
From: Josh Poimboeuf @ 2020-03-31 22:04 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: Peter Zijlstra, linux-kernel
On Mon, Mar 30, 2020 at 07:20:40PM -0500, Gustavo A. R. Silva wrote:
> In case func is null, there is a null pointer dereference at 2029:
>
> 2029 WARN("%s uses BP as a scratch register",
> 2030 func->name);
>
> Fix this by null-checking func.
>
> Addresses-Coverity-ID: 1492002 ("Dereference after null check")
> Fixes: c705cecc8431 ("objtool: Track original function across branches")
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> tools/objtool/check.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index e3bb76358148..182cc48fa892 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -2025,7 +2025,7 @@ static int validate_return(struct symbol *func, struct instruction *insn, struct
> return 1;
> }
>
> - if (state->bp_scratch) {
> + if (func && state->bp_scratch) {
> WARN("%s uses BP as a scratch register",
> func->name);
> return 1;
We should still do the warning even if there's no func. I'll make a
slightly different patch which unconditionally uses WARN_FUNC().
I'll give you Reported-by credit and keep the coverity tag. Thanks!
--
Josh
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] objtool: check: Fix NULL pointer dereference
2020-03-31 22:04 ` Josh Poimboeuf
@ 2020-03-31 22:27 ` Gustavo A. R. Silva
0 siblings, 0 replies; 3+ messages in thread
From: Gustavo A. R. Silva @ 2020-03-31 22:27 UTC (permalink / raw)
To: Josh Poimboeuf; +Cc: Peter Zijlstra, linux-kernel
On 3/31/20 17:04, Josh Poimboeuf wrote:
> On Mon, Mar 30, 2020 at 07:20:40PM -0500, Gustavo A. R. Silva wrote:
>> In case func is null, there is a null pointer dereference at 2029:
>>
>> 2029 WARN("%s uses BP as a scratch register",
>> 2030 func->name);
>>
>> Fix this by null-checking func.
>>
>> Addresses-Coverity-ID: 1492002 ("Dereference after null check")
>> Fixes: c705cecc8431 ("objtool: Track original function across branches")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>> tools/objtool/check.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
>> index e3bb76358148..182cc48fa892 100644
>> --- a/tools/objtool/check.c
>> +++ b/tools/objtool/check.c
>> @@ -2025,7 +2025,7 @@ static int validate_return(struct symbol *func, struct instruction *insn, struct
>> return 1;
>> }
>>
>> - if (state->bp_scratch) {
>> + if (func && state->bp_scratch) {
>> WARN("%s uses BP as a scratch register",
>> func->name);
>> return 1;
>
> We should still do the warning even if there's no func. I'll make a
> slightly different patch which unconditionally uses WARN_FUNC().
>
Awesome. :)
> I'll give you Reported-by credit and keep the coverity tag. Thanks!
>
Great.
Thanks
--
Gustavo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-03-31 0:20 [PATCH] objtool: check: Fix NULL pointer dereference Gustavo A. R. Silva
2020-03-31 22:04 ` Josh Poimboeuf
2020-03-31 22:27 ` Gustavo A. R. Silva
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