[PATCH v6 07/26] powerpc/secvar: Handle format string in the consumer
From: Andrew Donnellan <hidden>
Date: 2023-02-10 08:04:51
Also in:
linux-integrity, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: Russell Currey <redacted>
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 <redacted>
Signed-off-by: Andrew Donnellan <redacted>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
v2: Use sysfs_emit() instead of sprintf() (gregkh)
v3: Enforce format string size limit (ruscur)
v4: Pass the buffer size as an argument, not using a macro (stefanb,
npiggin)
Fix error reporting (npiggin)
---
arch/powerpc/include/asm/secvar.h | 1 +
arch/powerpc/kernel/secvar-sysfs.c | 27 +++++++-------------
arch/powerpc/platforms/powernv/opal-secvar.c | 25 ++++++++++++++++++
3 files changed, 35 insertions(+), 18 deletions(-)
diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
index a2b5f2203dc5..1a2c696a48ad 100644
--- a/arch/powerpc/include/asm/secvar.h
+++ b/arch/powerpc/include/asm/secvar.h@@ -17,6 +17,7 @@ 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, size_t bufsize); }; #ifdef CONFIG_PPC_SECURE_BOOT
diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c
index b786d1005027..e4661559c855 100644
--- a/arch/powerpc/kernel/secvar-sysfs.c
+++ b/arch/powerpc/kernel/secvar-sysfs.c@@ -21,26 +21,17 @@ 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[32]; + ssize_t len = secvar_ops->format(tmp, sizeof(tmp)); - rc = of_property_read_string(node, "format", &format); - if (rc) - goto out; + if (len > 0) + return sysfs_emit(buf, "%s\n", tmp); + else if (len < 0) + pr_err("Error %zd reading format string\n", len); + else + pr_err("Got empty format string from backend\n"); - rc = sysfs_emit(buf, "%s\n", format); - -out: - of_node_put(node); - - return rc; + return -EIO; }
diff --git a/arch/powerpc/platforms/powernv/opal-secvar.c b/arch/powerpc/platforms/powernv/opal-secvar.c
index 4c0a3b030fe0..e33bb703ecbc 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, size_t bufsize) +{ + 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, bufsize, "%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)
--
2.39.1