fs/kernel_read_file: Add file_size output argument

In preparation for adding partial read support, add an optional output
argument to kernel_read_file*() that reports the file size so callers
can reason more easily about their reading progress.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-8-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 6df1bdc..d9a1801 100644 (file)
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -500,6 +500,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 
                /* load firmware files from the mount namespace of init */
                rc = kernel_read_file_from_path_initns(path, &buffer, msize,
+                                                      NULL,
                                                       READING_FIRMWARE);
                if (rc < 0) {
                        if (rc != -ENOENT)

diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index e21a760..2e29c38 100644 (file)
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -14,6 +14,8 @@
  *             @buf_size will be ignored)
  * @buf_size   size of buf, if already allocated. If @buf not
  *             allocated, this is the largest size to allocate.
+ * @file_size  if non-NULL, the full size of @file will be
+ *             written here.
  * @id         the kernel_read_file_id identifying the type of
  *             file contents being read (for LSMs to examine)
  *
@@ -22,7 +24,8 @@
  *
  */
 int kernel_read_file(struct file *file, void **buf,
-                    size_t buf_size, enum kernel_read_file_id id)
+                    size_t buf_size, size_t *file_size,
+                    enum kernel_read_file_id id)
 {
        loff_t i_size, pos;
        ssize_t bytes = 0;
@@ -49,6 +52,8 @@ int kernel_read_file(struct file *file, void **buf,
                ret = -EFBIG;
                goto out;
        }
+       if (file_size)
+               *file_size = i_size;
 
        if (!*buf)
                *buf = allocated = vmalloc(i_size);
@@ -91,7 +96,8 @@ out:
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
 int kernel_read_file_from_path(const char *path, void **buf,
-                              size_t buf_size, enum kernel_read_file_id id)
+                              size_t buf_size, size_t *file_size,
+                              enum kernel_read_file_id id)
 {
        struct file *file;
        int ret;
@@ -103,14 +109,14 @@ int kernel_read_file_from_path(const char *path, void **buf,
        if (IS_ERR(file))
                return PTR_ERR(file);
 
-       ret = kernel_read_file(file, buf, buf_size, id);
+       ret = kernel_read_file(file, buf, buf_size, file_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,
-                                     size_t buf_size,
+                                     size_t buf_size, size_t *file_size,
                                      enum kernel_read_file_id id)
 {
        struct file *file;
@@ -129,13 +135,14 @@ 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, buf_size, id);
+       ret = kernel_read_file(file, buf, buf_size, file_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, size_t buf_size,
+                            size_t *file_size,
                             enum kernel_read_file_id id)
 {
        struct fd f = fdget(fd);
@@ -144,7 +151,7 @@ int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size,
        if (!f.file)
                goto out;
 
-       ret = kernel_read_file(f.file, buf, buf_size, id);
+       ret = kernel_read_file(f.file, buf, buf_size, file_size, id);
 out:
        fdput(f);
        return ret;

diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h
index 910039e..023293e 100644 (file)
--- a/include/linux/kernel_read_file.h
+++ b/include/linux/kernel_read_file.h
@@ -37,15 +37,19 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 
 int kernel_read_file(struct file *file,
                     void **buf, size_t buf_size,
+                    size_t *file_size,
                     enum kernel_read_file_id id);
 int kernel_read_file_from_path(const char *path,
                               void **buf, size_t buf_size,
+                              size_t *file_size,
                               enum kernel_read_file_id id);
 int kernel_read_file_from_path_initns(const char *path,
                                      void **buf, size_t buf_size,
+                                     size_t *file_size,
                                      enum kernel_read_file_id id);
 int kernel_read_file_from_fd(int fd,
                             void **buf, size_t buf_size,
+                            size_t *file_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 b20cfde..ee51c10 100644 (file)
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -222,7 +222,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
        void *ldata;
 
        ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
-                                      INT_MAX, READING_KEXEC_IMAGE);
+                                      INT_MAX, NULL, READING_KEXEC_IMAGE);
        if (ret < 0)
                return ret;
        image->kernel_buf_len = ret;
@@ -242,7 +242,7 @@ 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,
-                                              INT_MAX,
+                                              INT_MAX, NULL,
                                               READING_KEXEC_INITRAMFS);
                if (ret < 0)
                        goto out;

diff --git a/kernel/module.c b/kernel/module.c
index 9faa632..0f11eae 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4048,7 +4048,7 @@ 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, INT_MAX,
+       err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, NULL,
                                       READING_MODULE);
        if (err < 0)
                return err;

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 04f779c..8a523df 100644 (file)
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -175,7 +175,7 @@ int __init integrity_load_x509(const unsigned int id, const char *path)
        int rc;
        key_perm_t perm;
 
-       rc = kernel_read_file_from_path(path, &data, INT_MAX,
+       rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL,
                                        READING_X509_CERTIFICATE);
        if (rc < 0) {
                pr_err("Unable to open file: %s (%d)", path, rc);

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 692b83e..5fc56cc 100644 (file)
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -284,7 +284,7 @@ static ssize_t ima_read_policy(char *path)
        datap = path;
        strsep(&datap, "\n");
 
-       rc = kernel_read_file_from_path(path, &data, INT_MAX, READING_POLICY);
+       rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL, READING_POLICY);
        if (rc < 0) {
                pr_err("Unable to open file: %s (%d)", path, rc);
                return rc;