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SubjectRe: [PATCH v2 2/2] crypto: ccp - Fail the PSP initialization when writing psp data file failed
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On 8/16/22 14:32, Jacky Li wrote:
> Currently the OS continues the PSP initialization when there is a write
> failure to the init_ex_file. Therefore, the userspace would be told that
> SEV is properly INIT'd even though the psp data file is not updated.
> This is problematic because later when asked for the SEV data, the OS
> won't be able to provide it.
>
> Fixes: 3d725965f836 ("crypto: ccp - Add SEV_INIT_EX support")
> Reported-by: Peter Gonda <pgonda@google.com>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Jacky Li <jackyli@google.com>

Acked-by: Tom Lendacky <thomas.lendacky@amd.com>

> ---
> Changelog since v1:
> - Add a blank line after the variable declaration.
> - Fix the string format of the error code.
>
> drivers/crypto/ccp/sev-dev.c | 26 +++++++++++++++-----------
> 1 file changed, 15 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index fb7ca45a2f0d..ab1f76549ef8 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -237,7 +237,7 @@ static int sev_read_init_ex_file(void)
> return 0;
> }
>
> -static void sev_write_init_ex_file(void)
> +static int sev_write_init_ex_file(void)
> {
> struct sev_device *sev = psp_master->sev_data;
> struct file *fp;
> @@ -247,14 +247,16 @@ static void sev_write_init_ex_file(void)
> lockdep_assert_held(&sev_cmd_mutex);
>
> if (!sev_init_ex_buffer)
> - return;
> + return 0;
>
> fp = open_file_as_root(init_ex_path, O_CREAT | O_WRONLY, 0600);
> if (IS_ERR(fp)) {
> + int ret = PTR_ERR(fp);
> +
> dev_err(sev->dev,
> - "SEV: could not open file for write, error %ld\n",
> - PTR_ERR(fp));
> - return;
> + "SEV: could not open file for write, error %d\n",
> + ret);
> + return ret;
> }
>
> nwrite = kernel_write(fp, sev_init_ex_buffer, NV_LENGTH, &offset);
> @@ -265,18 +267,20 @@ static void sev_write_init_ex_file(void)
> dev_err(sev->dev,
> "SEV: failed to write %u bytes to non volatile memory area, ret %ld\n",
> NV_LENGTH, nwrite);
> - return;
> + return -EIO;
> }
>
> dev_dbg(sev->dev, "SEV: write successful to NV file\n");
> +
> + return 0;
> }
>
> -static void sev_write_init_ex_file_if_required(int cmd_id)
> +static int sev_write_init_ex_file_if_required(int cmd_id)
> {
> lockdep_assert_held(&sev_cmd_mutex);
>
> if (!sev_init_ex_buffer)
> - return;
> + return 0;
>
> /*
> * Only a few platform commands modify the SPI/NV area, but none of the
> @@ -291,10 +295,10 @@ static void sev_write_init_ex_file_if_required(int cmd_id)
> case SEV_CMD_PEK_GEN:
> break;
> default:
> - return;
> + return 0;
> }
>
> - sev_write_init_ex_file();
> + return sev_write_init_ex_file();
> }
>
> static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
> @@ -367,7 +371,7 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
> cmd, reg & PSP_CMDRESP_ERR_MASK);
> ret = -EIO;
> } else {
> - sev_write_init_ex_file_if_required(cmd);
> + ret = sev_write_init_ex_file_if_required(cmd);
> }
>
> print_hex_dump_debug("(out): ", DUMP_PREFIX_OFFSET, 16, 2, data,

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