| Message ID | 20230118061049.1006141-5-ajd@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | pSeries dynamic secure boot secvar interface + platform keyring loading | expand |
On Wed Jan 18, 2023 at 4:10 PM AEST, Andrew Donnellan wrote: > From: Russell Currey <ruscur@russell.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@russell.cc> > Signed-off-by: Andrew Donnellan <ajd@linux.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
On Wed Jan 18, 2023 at 4:10 PM AEST, Andrew Donnellan wrote: > From: Russell Currey <ruscur@russell.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@russell.cc> > Signed-off-by: Andrew Donnellan <ajd@linux.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); > }; > > #ifdef CONFIG_PPC_SECURE_BOOT > diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c > index 462cacc0ca60..d3858eedd72c 100644 > --- a/arch/powerpc/kernel/secvar-sysfs.c > +++ b/arch/powerpc/kernel/secvar-sysfs.c > @@ -21,26 +21,13 @@ static struct kset *secvar_kset; > static ssize_t format_show(struct kobject *kobj, struct kobj_attribute *attr, > char *buf) > { > - ssize_t rc = 0; > - struct device_node *node; > - const char *format; > - > - node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend"); > - if (!of_device_is_available(node)) { > - rc = -ENODEV; > - goto out; > - } > + char tmp[SECVAR_MAX_FORMAT_LEN]; > + ssize_t len = secvar_ops->format(tmp); > > - rc = of_property_read_string(node, "format", &format); > - if (rc) > - goto out; > + if (len <= 0) > + return -EIO; AFAIKS this does have a functional change, it loses the return value. Why not return len if it is < 0, and -EIO if len == 0? Thanks, Nick
On Thu, 2023-01-19 at 11:17 +1000, Nicholas Piggin wrote: > On Wed Jan 18, 2023 at 4:10 PM AEST, Andrew Donnellan wrote: > > From: Russell Currey <ruscur@russell.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@russell.cc> > > Signed-off-by: Andrew Donnellan <ajd@linux.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); > > }; > > > > #ifdef CONFIG_PPC_SECURE_BOOT > > diff --git a/arch/powerpc/kernel/secvar-sysfs.c > > b/arch/powerpc/kernel/secvar-sysfs.c > > index 462cacc0ca60..d3858eedd72c 100644 > > --- a/arch/powerpc/kernel/secvar-sysfs.c > > +++ b/arch/powerpc/kernel/secvar-sysfs.c > > @@ -21,26 +21,13 @@ static struct kset *secvar_kset; > > static ssize_t format_show(struct kobject *kobj, struct > > kobj_attribute *attr, > > char *buf) > > { > > - ssize_t rc = 0; > > - struct device_node *node; > > - const char *format; > > - > > - node = of_find_compatible_node(NULL, NULL, "ibm,secvar- > > backend"); > > - if (!of_device_is_available(node)) { > > - rc = -ENODEV; > > - goto out; > > - } > > + char tmp[SECVAR_MAX_FORMAT_LEN]; > > + ssize_t len = secvar_ops->format(tmp); > > > > - rc = of_property_read_string(node, "format", &format); > > - if (rc) > > - goto out; > > + if (len <= 0) > > + return -EIO; > > AFAIKS this does have a functional change, it loses the return value. > Why not return len if it is < 0, and -EIO if len == 0? In v2 mpe suggested the following: I'm not sure you should pass that raw error back to sysfs. Some of the values could be confusing, eg. if you return -EINVAL it looks like a parameter to the read() syscall was invalid. Might be better to just return -EIO. Following that advice, I don't think we should return something other than -EIO, but we should at least pr_err() to document the error - this isn't something that should ever fail. > > Thanks, > Nick
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); }; #ifdef CONFIG_PPC_SECURE_BOOT diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c index 462cacc0ca60..d3858eedd72c 100644 --- a/arch/powerpc/kernel/secvar-sysfs.c +++ b/arch/powerpc/kernel/secvar-sysfs.c @@ -21,26 +21,13 @@ static struct kset *secvar_kset; static ssize_t format_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { - ssize_t rc = 0; - struct device_node *node; - const char *format; - - node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend"); - if (!of_device_is_available(node)) { - rc = -ENODEV; - goto out; - } + char tmp[SECVAR_MAX_FORMAT_LEN]; + ssize_t len = secvar_ops->format(tmp); - rc = of_property_read_string(node, "format", &format); - if (rc) - goto out; + if (len <= 0) + return -EIO; - rc = sysfs_emit(buf, "%s\n", format); - -out: - of_node_put(node); - - return rc; + return sysfs_emit(buf, "%s\n", tmp); } diff --git a/arch/powerpc/platforms/powernv/opal-secvar.c b/arch/powerpc/platforms/powernv/opal-secvar.c index ef89861569e0..623c6839e66c 100644 --- a/arch/powerpc/platforms/powernv/opal-secvar.c +++ b/arch/powerpc/platforms/powernv/opal-secvar.c @@ -98,10 +98,35 @@ static int opal_set_variable(const char *key, u64 ksize, u8 *data, u64 dsize) return opal_status_to_err(rc); } +static ssize_t opal_secvar_format(char *buf) +{ + ssize_t rc = 0; + struct device_node *node; + const char *format; + + node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend"); + if (!of_device_is_available(node)) { + rc = -ENODEV; + goto out; + } + + rc = of_property_read_string(node, "format", &format); + if (rc) + goto out; + + rc = snprintf(buf, SECVAR_MAX_FORMAT_LEN, "%s", format); + +out: + of_node_put(node); + + return rc; +} + static const struct secvar_operations opal_secvar_ops = { .get = opal_get_variable, .get_next = opal_get_next_variable, .set = opal_set_variable, + .format = opal_secvar_format, }; static int opal_secvar_probe(struct platform_device *pdev)