Linux-ARM-MSM Archive on lore.kernel.org
 help / color / Atom feed
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,
	Scott Branden <scott.branden@broadcom.com>
Subject: [PATCH 1/7] fs: introduce kernel_pread_file* support
Date: Thu, 22 Aug 2019 12:24:45 -0700
Message-ID: <20190822192451.5983-2-scott.branden@broadcom.com> (raw)
In-Reply-To: <20190822192451.5983-1-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          | 77 ++++++++++++++++++++++++++++++++++++----------
 include/linux/fs.h | 15 +++++++++
 2 files changed, 75 insertions(+), 17 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index f7f6a140856a..21da8683e2c2 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -893,10 +893,14 @@ 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;
 
@@ -916,21 +920,31 @@ 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;
@@ -938,14 +952,16 @@ 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;
 
@@ -961,10 +977,20 @@ 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;
@@ -976,14 +1002,23 @@ 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_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;
@@ -991,11 +1026,19 @@ 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 997a530ff4e9..a257e98acc89 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2933,10 +2933,25 @@ 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_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 index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-22 19:24 [PATCH 0/7] firmware: add partial read support in request_firmware_into_buf Scott Branden
2019-08-22 19:24 ` Scott Branden [this message]
2019-08-23 12:29   ` [PATCH 1/7] fs: introduce kernel_pread_file* support Takashi Iwai
2019-08-23 19:55     ` Scott Branden
2019-08-23 21:29       ` Luis Chamberlain
2019-08-22 19:24 ` [PATCH 2/7] firmware: add offset to request_firmware_into_buf Scott Branden
2019-08-22 19:47   ` Luis Chamberlain
2019-08-22 20:07     ` Scott Branden
2019-08-22 21:12       ` Luis Chamberlain
2019-08-22 23:30         ` Scott Branden
2019-08-23 15:47           ` Luis Chamberlain
2019-08-23 20:16             ` Scott Branden
2019-08-23 10:05   ` Takashi Iwai
2019-08-23 19:44     ` Scott Branden
2019-08-26 15:20       ` Takashi Iwai
2019-08-26 15:41         ` Scott Branden
2019-08-26 15:57           ` Takashi Iwai
2019-08-26 17:12           ` Takashi Iwai
2019-08-26 17:24             ` Scott Branden
2019-08-27 10:40               ` Takashi Iwai
2019-10-11 13:31                 ` Luis Chamberlain
2019-08-22 19:24 ` [PATCH 3/7] test_firmware: add partial read support for request_firmware_into_buf Scott Branden
2019-08-22 19:24 ` [PATCH 4/7] selftests: firmware: Test partial file reads of request_firmware_into_buf Scott Branden
2019-08-22 19:24 ` [PATCH 5/7] bcm-vk: add bcm_vk UAPI Scott Branden
2019-08-27 13:54   ` Arnd Bergmann
2019-08-27 14:49   ` Kieran Bingham
2019-10-08 15:59     ` Olof Johansson
2019-08-22 19:24 ` [PATCH 6/7] misc: bcm-vk: add Broadcom Valkyrie driver Scott Branden
2019-08-27 14:14   ` Arnd Bergmann
2019-08-27 15:25     ` Nicolas Dufresne
2019-08-22 19:24 ` [PATCH 7/7] MAINTAINERS: bcm-vk: Add maintainer for Broadcom Valkyrie Driver Scott Branden

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190822192451.5983-2-scott.branden@broadcom.com \
    --to=scott.branden@broadcom.com \
    --cc=akpm@linux-foundation.org \
    --cc=arnd@arndb.de \
    --cc=bcm-kernel-feedback-list@broadcom.com \
    --cc=bjorn.andersson@linaro.org \
    --cc=colin.king@canonical.com \
    --cc=dan.carpenter@oracle.com \
    --cc=david.brown@linaro.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=keescook@chromium.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=mcgrof@kernel.org \
    --cc=olof@lixom.net \
    --cc=rafael@kernel.org \
    --cc=shuah@kernel.org \
    --cc=skhan@linuxfoundation.org \
    --cc=tiwai@suse.de \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ARM-MSM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-msm/0 linux-arm-msm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-msm linux-arm-msm/ https://lore.kernel.org/linux-arm-msm \
		linux-arm-msm@vger.kernel.org
	public-inbox-index linux-arm-msm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-arm-msm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git