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Fri, 20 Jan 2023 18:43:29 +1100 (AEDT) From: Andrew Donnellan To: linuxppc-dev@lists.ozlabs.org, linux-integrity@vger.kernel.org Cc: gregkh@linuxfoundation.org, gcwilson@linux.ibm.com, linux-kernel@vger.kernel.org, nayna@linux.ibm.com, ruscur@russell.cc, zohar@linux.ibm.com, mpe@ellerman.id.au, gjoyce@linux.ibm.com, sudhakar@linux.ibm.com, bgray@linux.ibm.com, erichte@linux.ibm.com, joel@jms.id.au Subject: [PATCH v4 06/24] powerpc/secvar: Handle format string in the consumer Date: Fri, 20 Jan 2023 18:42:48 +1100 Message-Id: <20230120074306.1326298-7-ajd@linux.ibm.com> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230120074306.1326298-1-ajd@linux.ibm.com> References: <20230120074306.1326298-1-ajd@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: mCmBB8A1PhQR84L8b4peojLVVGSZ7w-z X-Proofpoint-ORIG-GUID: mCmBB8A1PhQR84L8b4peojLVVGSZ7w-z X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.122.1 definitions=2023-01-20_04,2023-01-19_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 mlxlogscore=999 bulkscore=0 suspectscore=0 malwarescore=0 priorityscore=1501 spamscore=0 impostorscore=0 clxscore=1015 adultscore=0 phishscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301200070 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Russell Currey 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 Signed-off-by: Andrew Donnellan --- 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 4ce3f12c5613..2d9816dff128 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 462cacc0ca60..4beec935f5e7 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)