[PATCH] pstore/ram: Return directly after a failed kasprintf() call in ramoops_init_prz()

[PATCH] pstore/ram: Return directly after a failed kasprintf() call in ramoops_init_prz()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Wed, 17 Jan 2024 21:09:22 +0100

The result from a call of the function “kasprintf” was passed to
a subsequent function call without checking for a null pointer before
(according to a memory allocation failure).
This issue was detected by using the Coccinelle software.

Thus return directly after a failed kasprintf() call.

Fixes: 1227daa43bce1 ("pstore/ram: Clarify resource reservation labels")
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 fs/pstore/ram.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 88b34fdbf759..1a673a4af17c 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -595,6 +595,9 @@ static int ramoops_init_prz(const char *name,
 	}

 	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
+	if (!label)
+		return -ENOMEM;
+
 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
 				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
 	kfree(label);
--
2.43.0

Re: [PATCH] pstore/ram: Return directly after a failed kasprintf() call in ramoops_init_prz()

[Kunwu Chan]

Hi Markus,
Thanks for your patch.

On 2024/1/18 04:24, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Wed, 17 Jan 2024 21:09:22 +0100
> 
> The result from a call of the function “kasprintf” was passed to
> a subsequent function call without checking for a null pointer before
> (according to a memory allocation failure).
> This issue was detected by using the Coccinelle software.
> 
> Thus return directly after a failed kasprintf() call.
> 
> Fixes: 1227daa43bce1 ("pstore/ram: Clarify resource reservation labels")
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>   fs/pstore/ram.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index 88b34fdbf759..1a673a4af17c 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -595,6 +595,9 @@ static int ramoops_init_prz(const char *name,
>   	}
> 
>   	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
> +	if (!label)
> +		return -ENOMEM;
> +

This part looks good to me.

Commit 1227daa43bce1 ("pstore/ram: Clarify resource reservation labels")
introduce another two more kasprintf in the ramoops_init_przs.

Could you fix it together?
>   	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
>   				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
>   	kfree(label);
> --
> 2.43.0
> 
-- 
Thanks,
   Kunwu

Re: [PATCH] pstore/ram: Return directly after a failed kasprintf() call in ramoops_init_prz()

[Dan Carpenter]

On Wed, Jan 17, 2024 at 09:24:12PM +0100, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Wed, 17 Jan 2024 21:09:22 +0100
> 
> The result from a call of the function “kasprintf” was passed to
> a subsequent function call without checking for a null pointer before
> (according to a memory allocation failure).
> This issue was detected by using the Coccinelle software.
> 
> Thus return directly after a failed kasprintf() call.
> 
> Fixes: 1227daa43bce1 ("pstore/ram: Clarify resource reservation labels")
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  fs/pstore/ram.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index 88b34fdbf759..1a673a4af17c 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -595,6 +595,9 @@ static int ramoops_init_prz(const char *name,
>  	}
> 
>  	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
> +	if (!label)
> +		return -ENOMEM;
> +
>  	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
>  				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
>  	kfree(label);

This patch is fine as a clean up, but I think it's useful to say that
if you pass a NULL label to persistent_ram_new() then it will return
an error.  It won't crash.  So this patch is a nice cleanup but it's not
a bug fix.

regards,
dan carpenter

Re: [PATCH] pstore/ram: Return directly after a failed kasprintf() call in ramoops_init_prz()

[Markus Elfring]

>> The result from a call of the function “kasprintf” was passed to
>> a subsequent function call without checking for a null pointer before
>> (according to a memory allocation failure).
>> This issue was detected by using the Coccinelle software.
…
>> +++ b/fs/pstore/ram.c
>> @@ -595,6 +595,9 @@ static int ramoops_init_prz(const char *name,
>>  	}
>>
>>  	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
>> +	if (!label)
>> +		return -ENOMEM;
>> +
>>  	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
>>  				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
>>  	kfree(label);
>
> This patch is fine as a clean up, but I think it's useful to say that
> if you pass a NULL label to persistent_ram_new() then it will return
> an error.
…

Will it become helpful to annotate the corresponding function input parameter
for null pointer tolerance anyhow?

Regards,
Markus