2023-01-18 07:32:53

by Andrew Donnellan

Subject: [PATCH v3 13/24] powerpc/pseries: Fix handling of PLPKS object flushing timeout

plpks_confirm_object_flushed() uses the H_PKS_CONFIRM_OBJECT_FLUSHED hcall
to check whether changes to an object in the Platform KeyStore have been
flushed to non-volatile storage.

The hcall returns two output values, the return code and the flush status.
plpks_confirm_object_flushed() polls the hcall until either the flush
status has updated, the return code is an error, or a timeout has been
exceeded.

While we're still polling, the hcall is returning H_SUCCESS (0) as the
return code. In the timeout case, this means that upon exiting the polling
loop, rc is 0, and therefore 0 is returned to the user.

Handle the timeout case separately and return ETIMEDOUT if triggered.

Fixes: 2454a7af0f2a ("powerpc/pseries: define driver for Platform KeyStore")
Reported-by: Benjamin Gray <[email protected]>
Signed-off-by: Andrew Donnellan <[email protected]>
Tested-by: Russell Currey <[email protected]>
Reviewed-by: Russell Currey <[email protected]>
Signed-off-by: Russell Currey <[email protected]>

---

v3: Merge plpks fixes and signed update series with secvar series

Neaten how we return at the end of the function (ruscur)
---
arch/powerpc/platforms/pseries/plpks.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c
index 5bdc093de6fb..6d1303e4862d 100644
--- a/arch/powerpc/platforms/pseries/plpks.c
+++ b/arch/powerpc/platforms/pseries/plpks.c
@@ -234,6 +234,7 @@ static int plpks_confirm_object_flushed(struct label *label,
struct plpks_auth *auth)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
+ bool timed_out = true;
u64 timeout = 0;
u8 status;
int rc;
@@ -245,22 +246,26 @@ static int plpks_confirm_object_flushed(struct label *label,

status = retbuf[0];
if (rc) {
+ timed_out = false;
if (rc == H_NOT_FOUND && status == 1)
rc = 0;
break;
}

- if (!rc && status == 1)
+ if (!rc && status == 1) {
+ timed_out = false;
break;
+ }

usleep_range(PLPKS_FLUSH_SLEEP,
PLPKS_FLUSH_SLEEP + PLPKS_FLUSH_SLEEP_RANGE);
timeout = timeout + PLPKS_FLUSH_SLEEP;
} while (timeout < PLPKS_MAX_TIMEOUT);

- rc = pseries_status_to_err(rc);
+ if (timed_out)
+ return -ETIMEDOUT;

- return rc;
+ return pseries_status_to_err(rc);
}

int plpks_write_var(struct plpks_var var)
--
2.39.0

2023-01-19 01:24:29

by Nicholas Piggin

Subject: Re: [PATCH v3 13/24] powerpc/pseries: Fix handling of PLPKS object flushing timeout

On Wed Jan 18, 2023 at 4:10 PM AEST, Andrew Donnellan wrote:
> plpks_confirm_object_flushed() uses the H_PKS_CONFIRM_OBJECT_FLUSHED hcall
> to check whether changes to an object in the Platform KeyStore have been
> flushed to non-volatile storage.
>
> The hcall returns two output values, the return code and the flush status.
> plpks_confirm_object_flushed() polls the hcall until either the flush
> status has updated, the return code is an error, or a timeout has been
> exceeded.
>
> While we're still polling, the hcall is returning H_SUCCESS (0) as the
> return code. In the timeout case, this means that upon exiting the polling
> loop, rc is 0, and therefore 0 is returned to the user.
>
> Handle the timeout case separately and return ETIMEDOUT if triggered.
>
> Fixes: 2454a7af0f2a ("powerpc/pseries: define driver for Platform KeyStore")

Can fixes go to the start of the series?

Thanks,
Nick