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b=H4sIAIG/E2UC/x2NwQrCMBAFf6Xs2YUYKTH+iojY5Gn30DTsllIp/ XeDx4FhZieDCoxu3U6KVUzm0uB86iiNr/IBS25M3vmLiz6wLVpS/XJWWaHGk1hioOo8NXV5XuN YYRsnHlxE7nsXhpCp9ariLdv/dX8cxw+rCT1JewAAAA== X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1695793026; l=2217; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=YmUsybfVQe5zWGf5jAxBKfMLPjPHkISPd1MoaRXDQM0=; b=NnPpHhicfwRq3aw0g0ffOiYeu9GpDcJMkqekY6y7VMB3EAjMVg8b06HE/BZGpYy5L/gyLcJUP aMjUtWcfbOrCSXGxoVEFAkSnAjny2kZpdesatoBbkprjuWZXvxOIMzT X-Mailer: b4 0.12.3 Message-ID: <20230927-strncpy-drivers-misc-eeprom-idt_89hpesx-c-v1-1-08e3d45b8c05@google.com> Subject: [PATCH] eeprom: idt_89hpesx: replace open-coded kmemdup_nul From: Justin Stitt To: Arnd Bergmann , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Kees Cook , Justin Stitt X-Spam-Status: No, score=-8.4 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (morse.vger.email [0.0.0.0]); Tue, 26 Sep 2023 22:48:02 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778172311639645083 X-GMAIL-MSGID: 1778172311639645083 A malloc + strncpy + manual NUL_termination is just kmemdup_nul. Let's use this interface as it is less error-prone and more readable. Also drop `csraddr_len` as it is just used in a single place and we can just do the arithmetic in-line. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Cc: Kees Cook Signed-off-by: Justin Stitt Reviewed-by: Kees Cook --- Note: build-tested only. --- drivers/misc/eeprom/idt_89hpesx.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) --- base-commit: 6465e260f48790807eef06b583b38ca9789b6072 change-id: 20230927-strncpy-drivers-misc-eeprom-idt_89hpesx-c-b09ed5507b7d Best regards, -- Justin Stitt diff --git a/drivers/misc/eeprom/idt_89hpesx.c b/drivers/misc/eeprom/idt_89hpesx.c index 1d1f30b5c426..d807d08e2614 100644 --- a/drivers/misc/eeprom/idt_89hpesx.c +++ b/drivers/misc/eeprom/idt_89hpesx.c @@ -905,7 +905,7 @@ static ssize_t idt_dbgfs_csr_write(struct file *filep, const char __user *ubuf, { struct idt_89hpesx_dev *pdev = filep->private_data; char *colon_ch, *csraddr_str, *csrval_str; - int ret, csraddr_len; + int ret; u32 csraddr, csrval; char *buf; @@ -927,21 +927,16 @@ static ssize_t idt_dbgfs_csr_write(struct file *filep, const char __user *ubuf, * no new CSR value */ if (colon_ch != NULL) { - csraddr_len = colon_ch - buf; - csraddr_str = - kmalloc(csraddr_len + 1, GFP_KERNEL); + /* Copy the register address to the substring buffer */ + csraddr_str = kmemdup_nul(buf, colon_ch - buf, GFP_KERNEL); if (csraddr_str == NULL) { ret = -ENOMEM; goto free_buf; } - /* Copy the register address to the substring buffer */ - strncpy(csraddr_str, buf, csraddr_len); - csraddr_str[csraddr_len] = '\0'; /* Register value must follow the colon */ csrval_str = colon_ch + 1; } else /* if (str_colon == NULL) */ { csraddr_str = (char *)buf; /* Just to shut warning up */ - csraddr_len = strnlen(csraddr_str, count); csrval_str = NULL; }