1 files changed, 92 insertions, 0 deletions

diff --git a/fs/exec.c b/fs/exec.c
index dcd4ac7d3f1e..9bdf0edf570d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -56,6 +56,7 @@
 #include <linux/pipe_fs_i.h>
 #include <linux/oom.h>
 #include <linux/compat.h>
+#include <linux/vmalloc.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -831,6 +832,97 @@ int kernel_read(struct file *file, loff_t offset,
 
 EXPORT_SYMBOL(kernel_read);
 
+int kernel_read_file(struct file *file, void **buf, loff_t *size,
+                     loff_t max_size, enum kernel_read_file_id id)
+{
+        loff_t i_size, pos;
+        ssize_t bytes = 0;
+        int ret;
+
+        if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
+                return -EINVAL;
+
+        ret = security_kernel_read_file(file, id);
+        if (ret)
+                return ret;
+
+        i_size = i_size_read(file_inode(file));
+        if (max_size > 0 && i_size > max_size)
+                return -EFBIG;
+        if (i_size <= 0)
+                return -EINVAL;
+
+        *buf = vmalloc(i_size);
+        if (!*buf)
+                return -ENOMEM;
+
+        pos = 0;
+        while (pos < i_size) {
+                bytes = kernel_read(file, pos, (char *)(*buf) + pos,
+                                    i_size - pos);
+                if (bytes < 0) {
+                        ret = bytes;
+                        goto out;
+                }
+
+                if (bytes == 0)
+                        break;
+                pos += bytes;
+        }
+
+        if (pos != i_size) {
+                ret = -EIO;
+                goto out;
+        }
+
+        ret = security_kernel_post_read_file(file, *buf, i_size, id);
+        if (!ret)
+                *size = pos;
+
+out:
+        if (ret < 0) {
+                vfree(*buf);
+                *buf = NULL;
+        }
+        return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file);
+
+int kernel_read_file_from_path(char *path, void **buf, loff_t *size,
+                               loff_t max_size, enum kernel_read_file_id id)
+{
+        struct file *file;
+        int ret;
+
+        if (!path || !*path)
+                return -EINVAL;
+
+        file = filp_open(path, O_RDONLY, 0);
+        if (IS_ERR(file))
+                return PTR_ERR(file);
+
+        ret = kernel_read_file(file, buf, size, max_size, id);
+        fput(file);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
+
+int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
+                             enum kernel_read_file_id id)
+{
+        struct fd f = fdget(fd);
+        int ret = -EBADF;
+
+        if (!f.file)
+                goto out;
+
+        ret = kernel_read_file(f.file, buf, size, max_size, id);
+out:
+        fdput(f);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
+
 ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
 {
         ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);