| Message ID | 20230131063928.388035-13-ajd@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | pSeries dynamic secure boot secvar interface + platform keyring loading | expand |
On 1/31/23 01:39, Andrew Donnellan wrote: > Due to sysfs constraints, when writing to a variable, we can only handle > writes of up to PAGE_SIZE. > > It's possible that the maximum object size is larger than PAGE_SIZE, in > which case, print a warning on boot so that the user is aware. > > Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> > Signed-off-by: Russell Currey <ruscur@russell.cc> > > --- > > v3: New patch (ajd) > --- > arch/powerpc/kernel/secvar-sysfs.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c > index 2cbc60b37e4e..9b6be63b7b36 100644 > --- a/arch/powerpc/kernel/secvar-sysfs.c > +++ b/arch/powerpc/kernel/secvar-sysfs.c > @@ -223,6 +223,7 @@ static int secvar_sysfs_load_static(void) > > static int secvar_sysfs_init(void) > { > + u64 max_size; > int rc; > > if (!secvar_ops) { > @@ -272,6 +273,14 @@ static int secvar_sysfs_init(void) > goto err; > } > > + // Due to sysfs limitations, we will only ever get a write buffer of > + // up to 1 page in size. Print a warning if this is potentially going > + // to cause problems, so that the user is aware. > + secvar_ops->max_size(&max_size); > + if (max_size > PAGE_SIZE) > + pr_warn_ratelimited("PAGE_SIZE (%lu) is smaller than maximum object size (%llu), writes are limited to PAGE_SIZE\n", > + PAGE_SIZE, max_size); > + > return 0; > err: > kobject_put(secvar_kobj); Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c index 2cbc60b37e4e..9b6be63b7b36 100644 --- a/arch/powerpc/kernel/secvar-sysfs.c +++ b/arch/powerpc/kernel/secvar-sysfs.c @@ -223,6 +223,7 @@ static int secvar_sysfs_load_static(void) static int secvar_sysfs_init(void) { + u64 max_size; int rc; if (!secvar_ops) { @@ -272,6 +273,14 @@ static int secvar_sysfs_init(void) goto err; } + // Due to sysfs limitations, we will only ever get a write buffer of + // up to 1 page in size. Print a warning if this is potentially going + // to cause problems, so that the user is aware. + secvar_ops->max_size(&max_size); + if (max_size > PAGE_SIZE) + pr_warn_ratelimited("PAGE_SIZE (%lu) is smaller than maximum object size (%llu), writes are limited to PAGE_SIZE\n", + PAGE_SIZE, max_size); + return 0; err: kobject_put(secvar_kobj);