From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pl1-x644.google.com ([2607:f8b0:4864:20::644]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jyf7u-0007uK-Lo for kexec@lists.infradead.org; Thu, 23 Jul 2020 17:35:28 +0000 Received: by mail-pl1-x644.google.com with SMTP id m16so2860252pls.5 for ; Thu, 23 Jul 2020 10:35:26 -0700 (PDT) Subject: Re: [PATCH v2 08/18] fs/kernel_read_file: Remove redundant size argument References: <20200722193020.2676422-1-keescook@chromium.org> <20200722193020.2676422-9-keescook@chromium.org> From: Scott Branden Message-ID: <01389997-7d46-b793-a453-e21c3336dbe8@broadcom.com> Date: Thu, 23 Jul 2020 10:35:18 -0700 MIME-Version: 1.0 In-Reply-To: <20200722193020.2676422-9-keescook@chromium.org> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Kees Cook , Greg Kroah-Hartman Cc: linux-efi@vger.kernel.org, "Rafael J. Wysocki" , Peter Zijlstra , linux-fsdevel@vger.kernel.org, Stephen Boyd , SeongJae Park , Mimi Zohar , David Howells , Tushar Sugandhi , Peter Jones , linux-kselftest@vger.kernel.org, "Joel Fernandes (Google)" , Shuah Khan , Ard Biesheuvel , Thomas Cedeno , linux-security-module@vger.kernel.org, Anders Roxell , Paul Moore , Mauro Carvalho Chehab , Michael Ellerman , Nayna Jain , Matthew Garrett , James Morris , Lakshmi Ramasubramanian , Aaron Goidel , "Serge E. Hallyn" , Wenwen Wang , selinux@vger.kernel.org, Hans de Goede , Alexander Viro , Matthieu Baerts , KP Singh , Eric Paris , linux-integrity@vger.kernel.org, Florent Revest , Andrea Righi , Dmitry Kasatkin , Stephen Smalley , Randy Dunlap , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Luis Chamberlain , Eric Biederman , Dave Olsthoorn , Jessica Yu , Casey Schaufler , Joe Perches , Andrew Morton , Thiago Jung Bauermann works On 2020-07-22 12:30 p.m., Kees Cook wrote: > In preparation for refactoring kernel_read_file*(), remove the redundant > "size" argument which is not needed: it can be included in the return > code, with callers adjusted. (VFS reads already cannot be larger than > INT_MAX.) > > Signed-off-by: Kees Cook Acked-by: Scott Branden > --- > drivers/base/firmware_loader/main.c | 10 ++++++---- > fs/kernel_read_file.c | 20 +++++++++----------- > include/linux/kernel_read_file.h | 8 ++++---- > kernel/kexec_file.c | 14 +++++++------- > kernel/module.c | 7 +++---- > security/integrity/digsig.c | 5 +++-- > security/integrity/ima/ima_fs.c | 6 ++++-- > 7 files changed, 36 insertions(+), 34 deletions(-) > > diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c > index d4a413ea48ce..f80c0d102be8 100644 > --- a/drivers/base/firmware_loader/main.c > +++ b/drivers/base/firmware_loader/main.c > @@ -462,7 +462,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, > size_t in_size, > const void *in_buffer)) > { > - loff_t size; > + size_t size; > int i, len; > int rc = -ENOENT; > char *path; > @@ -494,10 +494,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, > fw_priv->size = 0; > > /* load firmware files from the mount namespace of init */ > - rc = kernel_read_file_from_path_initns(path, &buffer, > - &size, msize, > + rc = kernel_read_file_from_path_initns(path, &buffer, msize, > READING_FIRMWARE); > - if (rc) { > + if (rc < 0) { > if (rc != -ENOENT) > dev_warn(device, "loading %s failed with error %d\n", > path, rc); > @@ -506,6 +505,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, > path); > continue; > } > + size = rc; > + rc = 0; > + > dev_dbg(device, "Loading firmware from %s\n", path); > if (decompress) { > dev_dbg(device, "f/w decompressing %s\n", > diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c > index 54d972d4befc..dc28a8def597 100644 > --- a/fs/kernel_read_file.c > +++ b/fs/kernel_read_file.c > @@ -5,7 +5,7 @@ > #include > #include > > -int kernel_read_file(struct file *file, void **buf, loff_t *size, > +int kernel_read_file(struct file *file, void **buf, > loff_t max_size, enum kernel_read_file_id id) > { > loff_t i_size, pos; > @@ -29,7 +29,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > ret = -EINVAL; > goto out; > } > - if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) { > + if (i_size > INT_MAX || (max_size > 0 && i_size > max_size)) { > ret = -EFBIG; > goto out; > } > @@ -59,8 +59,6 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > } > > ret = security_kernel_post_read_file(file, *buf, i_size, id); > - if (!ret) > - *size = pos; > > out_free: > if (ret < 0) { > @@ -72,11 +70,11 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > > out: > allow_write_access(file); > - return ret; > + return ret == 0 ? pos : ret; > } > EXPORT_SYMBOL_GPL(kernel_read_file); > > -int kernel_read_file_from_path(const char *path, void **buf, loff_t *size, > +int kernel_read_file_from_path(const char *path, void **buf, > loff_t max_size, enum kernel_read_file_id id) > { > struct file *file; > @@ -89,14 +87,14 @@ int kernel_read_file_from_path(const char *path, void **buf, loff_t *size, > if (IS_ERR(file)) > return PTR_ERR(file); > > - ret = kernel_read_file(file, buf, size, max_size, id); > + ret = kernel_read_file(file, buf, max_size, id); > fput(file); > return ret; > } > EXPORT_SYMBOL_GPL(kernel_read_file_from_path); > > int kernel_read_file_from_path_initns(const char *path, void **buf, > - loff_t *size, loff_t max_size, > + loff_t max_size, > enum kernel_read_file_id id) > { > struct file *file; > @@ -115,13 +113,13 @@ int kernel_read_file_from_path_initns(const char *path, void **buf, > if (IS_ERR(file)) > return PTR_ERR(file); > > - ret = kernel_read_file(file, buf, size, max_size, id); > + ret = kernel_read_file(file, buf, max_size, id); > fput(file); > return ret; > } > EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); > > -int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, > +int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size, > enum kernel_read_file_id id) > { > struct fd f = fdget(fd); > @@ -130,7 +128,7 @@ int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, > if (!f.file) > goto out; > > - ret = kernel_read_file(f.file, buf, size, max_size, id); > + ret = kernel_read_file(f.file, buf, max_size, id); > out: > fdput(f); > return ret; > diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h > index 78cf3d7dc835..0ca0bdbed1bd 100644 > --- a/include/linux/kernel_read_file.h > +++ b/include/linux/kernel_read_file.h > @@ -36,16 +36,16 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) > } > > int kernel_read_file(struct file *file, > - void **buf, loff_t *size, loff_t max_size, > + void **buf, loff_t max_size, > enum kernel_read_file_id id); > int kernel_read_file_from_path(const char *path, > - void **buf, loff_t *size, loff_t max_size, > + void **buf, loff_t max_size, > enum kernel_read_file_id id); > int kernel_read_file_from_path_initns(const char *path, > - void **buf, loff_t *size, loff_t max_size, > + void **buf, loff_t max_size, > enum kernel_read_file_id id); > int kernel_read_file_from_fd(int fd, > - void **buf, loff_t *size, loff_t max_size, > + void **buf, loff_t max_size, > enum kernel_read_file_id id); > > #endif /* _LINUX_KERNEL_READ_FILE_H */ > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > index 1358069ce9e9..eda19ca256a3 100644 > --- a/kernel/kexec_file.c > +++ b/kernel/kexec_file.c > @@ -220,13 +220,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, > { > int ret; > void *ldata; > - loff_t size; > > ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, > - &size, INT_MAX, READING_KEXEC_IMAGE); > - if (ret) > + INT_MAX, READING_KEXEC_IMAGE); > + if (ret < 0) > return ret; > - image->kernel_buf_len = size; > + image->kernel_buf_len = ret; > > /* Call arch image probe handlers */ > ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, > @@ -243,11 +242,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, > /* It is possible that there no initramfs is being loaded */ > if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { > ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, > - &size, INT_MAX, > + INT_MAX, > READING_KEXEC_INITRAMFS); > - if (ret) > + if (ret < 0) > goto out; > - image->initrd_buf_len = size; > + image->initrd_buf_len = ret; > + ret = 0; > } > > if (cmdline_len) { > diff --git a/kernel/module.c b/kernel/module.c > index e9765803601b..b6fd4f51cc30 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -3988,7 +3988,6 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, > SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) > { > struct load_info info = { }; > - loff_t size; > void *hdr = NULL; > int err; > > @@ -4002,12 +4001,12 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) > |MODULE_INIT_IGNORE_VERMAGIC)) > return -EINVAL; > > - err = kernel_read_file_from_fd(fd, &hdr, &size, INT_MAX, > + err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, > READING_MODULE); > - if (err) > + if (err < 0) > return err; > info.hdr = hdr; > - info.len = size; > + info.len = err; > > return load_module(&info, uargs, flags); > } > diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c > index f8869be45d8f..97661ffabc4e 100644 > --- a/security/integrity/digsig.c > +++ b/security/integrity/digsig.c > @@ -171,16 +171,17 @@ int __init integrity_add_key(const unsigned int id, const void *data, > int __init integrity_load_x509(const unsigned int id, const char *path) > { > void *data = NULL; > - loff_t size; > + size_t size; > int rc; > key_perm_t perm; > > - rc = kernel_read_file_from_path(path, &data, &size, 0, > + rc = kernel_read_file_from_path(path, &data, 0, > READING_X509_CERTIFICATE); > if (rc < 0) { > pr_err("Unable to open file: %s (%d)", path, rc); > return rc; > } > + size = rc; > > perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ; > > diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c > index e13ffece3726..602f52717757 100644 > --- a/security/integrity/ima/ima_fs.c > +++ b/security/integrity/ima/ima_fs.c > @@ -275,7 +275,7 @@ static ssize_t ima_read_policy(char *path) > { > void *data = NULL; > char *datap; > - loff_t size; > + size_t size; > int rc, pathlen = strlen(path); > > char *p; > @@ -284,11 +284,13 @@ static ssize_t ima_read_policy(char *path) > datap = path; > strsep(&datap, "\n"); > > - rc = kernel_read_file_from_path(path, &data, &size, 0, READING_POLICY); > + rc = kernel_read_file_from_path(path, &data, 0, READING_POLICY); > if (rc < 0) { > pr_err("Unable to open file: %s (%d)", path, rc); > return rc; > } > + size = rc; > + rc = 0; > > datap = data; > while (size > 0 && (p = strsep(&datap, "\n"))) { _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec