linux-kernel - Re: [PATCH v3 04/24] powerpc/secvar: Handle format string in the consumer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <CPVRFKZUFEFE.3IPS9CFR9KPD6@bobo>
Date:   Thu, 19 Jan 2023 11:02:36 +1000
From:   "Nicholas Piggin" <npiggin@...il.com>
To:     "Andrew Donnellan" <ajd@...ux.ibm.com>,
        <linuxppc-dev@...ts.ozlabs.org>, <linux-integrity@...r.kernel.org>
Cc:     <sudhakar@...ux.ibm.com>, <bgray@...ux.ibm.com>,
        <erichte@...ux.ibm.com>, <gregkh@...uxfoundation.org>,
        <nayna@...ux.ibm.com>, <linux-kernel@...r.kernel.org>,
        <zohar@...ux.ibm.com>, <gjoyce@...ux.ibm.com>,
        <gcwilson@...ux.ibm.com>
Subject: Re: [PATCH v3 04/24] powerpc/secvar: Handle format string in the
 consumer

On Wed Jan 18, 2023 at 4:10 PM AEST, Andrew Donnellan wrote:
> From: Russell Currey <ruscur@...sell.cc>
>
> The code that handles the format string in secvar-sysfs.c is entirely
> OPAL specific, so create a new "format" op in secvar_operations to make
> the secvar code more generic.  No functional change.
>
> Signed-off-by: Russell Currey <ruscur@...sell.cc>
> Signed-off-by: Andrew Donnellan <ajd@...ux.ibm.com>
>
> ---
>
> v2: Use sysfs_emit() instead of sprintf() (gregkh)
>
> v3: Enforce format string size limit (ruscur)
> ---
>  arch/powerpc/include/asm/secvar.h            |  3 +++
>  arch/powerpc/kernel/secvar-sysfs.c           | 23 ++++--------------
>  arch/powerpc/platforms/powernv/opal-secvar.c | 25 ++++++++++++++++++++
>  3 files changed, 33 insertions(+), 18 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
> index 07ba36f868a7..8b6475589120 100644
> --- a/arch/powerpc/include/asm/secvar.h
> +++ b/arch/powerpc/include/asm/secvar.h
> @@ -11,12 +11,15 @@
>  #include <linux/types.h>
>  #include <linux/errno.h>
>  
> +#define SECVAR_MAX_FORMAT_LEN	30 // max length of string returned by ->format()
> +
>  extern const struct secvar_operations *secvar_ops;
>  
>  struct secvar_operations {
>  	int (*get)(const char *key, u64 key_len, u8 *data, u64 *data_size);
>  	int (*get_next)(const char *key, u64 *key_len, u64 keybufsize);
>  	int (*set)(const char *key, u64 key_len, u8 *data, u64 data_size);
> +	ssize_t (*format)(char *buf);

Maybe pass the buf size as an argument here? Which is a bit less error
prone and more flexible than finding the right #define for it.

Thanks,
Nick