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From: Scott Branden <scott.branden@broadcom.com>
To: Luis Chamberlain <mcgrof@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	David Brown <david.brown@linaro.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Shuah Khan <shuah@kernel.org>,
	bjorn.andersson@linaro.org,
	Shuah Khan <skhan@linuxfoundation.org>,
	Arnd Bergmann <arnd@arndb.de>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
	Olof Johansson <olof@lixom.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Colin Ian King <colin.king@canonical.com>,
	Kees Cook <keescook@chromium.org>, Takashi Iwai <tiwai@suse.de>,
	linux-kselftest@vger.kernel.org, Andy Gross <agross@kernel.org>,
	Scott Branden <scott.branden@broadcom.com>
Subject: [PATCH v5 1/7] fs: introduce kernel_pread_file* support
Date: Thu,  7 May 2020 17:27:33 -0700	[thread overview]
Message-ID: <20200508002739.19360-2-scott.branden@broadcom.com> (raw)
In-Reply-To: <20200508002739.19360-1-scott.branden@broadcom.com>

Add kernel_pread_file* support to kernel to allow for partial read
of files with an offset into the file.  Existing kernel_read_file
functions call new kernel_pread_file functions with offset=0 and
flags=KERNEL_PREAD_FLAG_WHOLE.

Signed-off-by: Scott Branden <scott.branden@broadcom.com>
---
 fs/exec.c          | 96 ++++++++++++++++++++++++++++++++++++----------
 include/linux/fs.h | 20 ++++++++++
 2 files changed, 95 insertions(+), 21 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 06b4c550af5d..cfab212fab9d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -896,10 +896,14 @@ struct file *open_exec(const char *name)
 }
 EXPORT_SYMBOL(open_exec);
 
-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;
+int kernel_pread_file(struct file *file, void **buf, loff_t *size,
+		      loff_t pos, loff_t max_size, unsigned int flags,
+		      enum kernel_read_file_id id)
+{
+	loff_t alloc_size;
+	loff_t buf_pos;
+	loff_t read_end;
+	loff_t i_size;
 	ssize_t bytes = 0;
 	int ret;
 
@@ -919,21 +923,31 @@ 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)) {
+
+	/* Default read to end of file */
+	read_end = i_size;
+
+	/* Allow reading partial portion of file */
+	if ((flags & KERNEL_PREAD_FLAG_PART) &&
+	    (i_size > (pos + max_size)))
+		read_end = pos + max_size;
+
+	alloc_size = read_end - pos;
+	if (i_size > SIZE_MAX || (max_size > 0 && alloc_size > max_size)) {
 		ret = -EFBIG;
 		goto out;
 	}
 
 	if (id != READING_FIRMWARE_PREALLOC_BUFFER)
-		*buf = vmalloc(i_size);
+		*buf = vmalloc(alloc_size);
 	if (!*buf) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	pos = 0;
-	while (pos < i_size) {
-		bytes = kernel_read(file, *buf + pos, i_size - pos, &pos);
+	buf_pos = 0;
+	while (pos < read_end) {
+		bytes = kernel_read(file, *buf + buf_pos, read_end - pos, &pos);
 		if (bytes < 0) {
 			ret = bytes;
 			goto out_free;
@@ -941,14 +955,16 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 
 		if (bytes == 0)
 			break;
+
+		buf_pos += bytes;
 	}
 
-	if (pos != i_size) {
+	if (pos != read_end) {
 		ret = -EIO;
 		goto out_free;
 	}
 
-	ret = security_kernel_post_read_file(file, *buf, i_size, id);
+	ret = security_kernel_post_read_file(file, *buf, alloc_size, id);
 	if (!ret)
 		*size = pos;
 
@@ -964,10 +980,20 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 	allow_write_access(file);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(kernel_pread_file);
+
+int kernel_read_file(struct file *file, void **buf, loff_t *size,
+		     loff_t max_size, enum kernel_read_file_id id)
+{
+	return kernel_pread_file(file, buf, size, 0, max_size,
+				 KERNEL_PREAD_FLAG_WHOLE, id);
+}
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
-int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
-			       loff_t max_size, enum kernel_read_file_id id)
+int kernel_pread_file_from_path(const char *path, void **buf,
+				loff_t *size, loff_t pos,
+				loff_t max_size, unsigned int flags,
+				enum kernel_read_file_id id)
 {
 	struct file *file;
 	int ret;
@@ -979,15 +1005,25 @@ 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_pread_file(file, buf, size, pos, max_size, flags, id);
 	fput(file);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(kernel_pread_file_from_path);
+
+int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
+			       loff_t max_size, enum kernel_read_file_id id)
+{
+	return kernel_pread_file_from_path(path, buf, size, 0, max_size,
+					   KERNEL_PREAD_FLAG_WHOLE, id);
+}
 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,
-				      enum kernel_read_file_id id)
+extern int kernel_pread_file_from_path_initns(const char *path, void **buf,
+					      loff_t *size, loff_t pos,
+					      loff_t max_size,
+					      unsigned int flags,
+					      enum kernel_read_file_id id)
 {
 	struct file *file;
 	struct path root;
@@ -1005,14 +1041,24 @@ 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_pread_file(file, buf, size, pos, max_size, flags, id);
 	fput(file);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(kernel_pread_file_from_path_initns);
+
+int kernel_read_file_from_path_initns(const char *path, void **buf,
+				      loff_t *size, loff_t max_size,
+				      enum kernel_read_file_id id)
+{
+	return kernel_pread_file_from_path_initns(path, buf, size, 0, max_size,
+						  KERNEL_PREAD_FLAG_WHOLE, id);
+}
 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,
-			     enum kernel_read_file_id id)
+int kernel_pread_file_from_fd(int fd, void **buf, loff_t *size, loff_t pos,
+			      loff_t max_size, unsigned int flags,
+			      enum kernel_read_file_id id)
 {
 	struct fd f = fdget(fd);
 	int ret = -EBADF;
@@ -1020,11 +1066,19 @@ 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_pread_file(f.file, buf, size, pos, max_size, flags, id);
 out:
 	fdput(f);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(kernel_pread_file_from_fd);
+
+int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
+			     enum kernel_read_file_id id)
+{
+	return kernel_pread_file_from_fd(fd, buf, size, 0, max_size,
+					 KERNEL_PREAD_FLAG_WHOLE, id);
+}
 EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
 
 ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 45cc10cdf6dd..4bba930b77d7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3014,12 +3014,32 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 	return kernel_read_file_str[id];
 }
 
+/* Flags used by kernel_pread_file functions */
+#define KERNEL_PREAD_FLAG_WHOLE	0x0000 /* Only Allow reading of whole file */
+#define KERNEL_PREAD_FLAG_PART	0x0001 /* Allow reading part of file */
+
+extern int kernel_pread_file(struct file *file, void **buf, loff_t *size,
+			     loff_t pos, loff_t max_size, unsigned int flags,
+			     enum kernel_read_file_id id);
 extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
 			    enum kernel_read_file_id);
+extern int kernel_pread_file_from_path(const char *path, void **buf,
+				       loff_t *size, loff_t pos,
+				       loff_t max_size, unsigned int flags,
+				       enum kernel_read_file_id id);
 extern int kernel_read_file_from_path(const char *, void **, loff_t *, loff_t,
 				      enum kernel_read_file_id);
+extern int kernel_pread_file_from_path_initns(const char *path, void **buf,
+					      loff_t *size, loff_t pos,
+					      loff_t max_size,
+					      unsigned int flags,
+					      enum kernel_read_file_id id);
 extern int kernel_read_file_from_path_initns(const char *, void **, loff_t *, loff_t,
 					     enum kernel_read_file_id);
+extern int kernel_pread_file_from_fd(int fd, void **buf, loff_t *size,
+				    loff_t pos, loff_t max_size,
+				    unsigned int flags,
+				    enum kernel_read_file_id id);
 extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
 				    enum kernel_read_file_id);
 extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
-- 
2.17.1


  reply	other threads:[~2020-05-08  0:28 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-08  0:27 [PATCH v5 0/7] firmware: add partial read support in request_firmware_into_buf Scott Branden
2020-05-08  0:27 ` Scott Branden [this message]
2020-05-13  0:27   ` [PATCH v5 1/7] fs: introduce kernel_pread_file* support Luis Chamberlain
2020-05-13  6:23     ` Scott Branden
2020-05-13  6:51       ` Greg Kroah-Hartman
2020-05-13  8:16         ` Scott Branden
2020-05-13 18:39   ` Mimi Zohar
2020-05-13 18:53     ` Scott Branden
2020-05-13 18:57       ` Scott Branden
2020-05-13 19:03       ` Mimi Zohar
2020-05-13 19:18         ` Scott Branden
2020-05-13 19:39           ` Mimi Zohar
2020-05-13 19:41             ` Scott Branden
2020-05-13 21:20               ` Mimi Zohar
2020-05-13 21:28                 ` Luis Chamberlain
2020-05-13 22:12                   ` Mimi Zohar
2020-05-13 22:48                     ` Scott Branden
2020-05-13 23:00                       ` Mimi Zohar
2020-05-13 23:34                         ` Kees Cook
2020-05-13 23:58                           ` Mimi Zohar
2020-05-08  0:27 ` [PATCH v5 2/7] firmware: add offset to request_firmware_into_buf Scott Branden
2020-05-13  0:33   ` Luis Chamberlain
2020-05-13 18:35     ` Scott Branden
2020-05-15 20:44       ` Luis Chamberlain
2020-05-08  0:27 ` [PATCH v5 3/7] test_firmware: add partial read support for request_firmware_into_buf Scott Branden
2020-05-13  0:35   ` Luis Chamberlain
2020-05-08  0:27 ` [PATCH v5 4/7] firmware: test partial file reads of request_firmware_into_buf Scott Branden
2020-05-08  0:27 ` [PATCH v5 5/7] bcm-vk: add bcm_vk UAPI Scott Branden
2020-05-08  0:27 ` [PATCH v5 7/7] MAINTAINERS: bcm-vk: add maintainer for Broadcom VK Driver Scott Branden
     [not found] ` <20200508002739.19360-7-scott.branden@broadcom.com>
2020-05-13  0:38   ` [PATCH v5 6/7] misc: bcm-vk: add Broadcom VK driver Luis Chamberlain
2020-05-13  6:31     ` Scott Branden
2020-05-13  6:50       ` Greg Kroah-Hartman
2020-05-13 12:30         ` Luis Chamberlain
2020-05-13 18:39           ` Scott Branden
2020-05-13 16:23 ` [PATCH v5 0/7] firmware: add partial read support in request_firmware_into_buf Mimi Zohar
2020-05-15 20:47   ` Luis Chamberlain
2020-05-15 23:28     ` Scott Branden
2020-05-16  1:05       ` Luis Chamberlain

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