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Commit 4c9ec219 authored by Kees Cook's avatar Kees Cook
Browse files

pstore: Remove write_buf() callback 



Now that write() and write_buf() are functionally identical, this removes
write_buf(), and renames write_buf_user() to write_user(). Additionally
adds sanity-checks for pstore_info's declared functions and flags at
registration time.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent fdd03118

fs/pstore/ftrace.c

+2 −2
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ static void notrace pstore_ftrace_call(unsigned long ip, 
	rec.parent_ip = parent_ip;

	pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);

	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());

	psinfo->write_buf(&record);

	psinfo->write(&record);



	local_irq_restore(flags);

}
@@ -122,7 +122,7 @@ void pstore_register_ftrace(void) 
{

	struct dentry *file;



	if (!psinfo->write_buf)

	if (!psinfo->write)

		return;



	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);

fs/pstore/platform.c

+20 −15
Original line number Diff line number Diff line
@@ -604,7 +604,7 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c) 
		}

		record.buf = (char *)s;

		record.size = c;

		psinfo->write_buf(&record);

		psinfo->write(&record);

		spin_unlock_irqrestore(&psinfo->buf_lock, flags);

		s += c;

		c = e - s;
@@ -632,14 +632,7 @@ static void pstore_register_console(void) {} 
static void pstore_unregister_console(void) {}

#endif



static int pstore_write_compat(struct pstore_record *record)

{

	record->buf = psinfo->buf;



	return record->psi->write_buf(record);

}



static int pstore_write_buf_user_compat(struct pstore_record *record,

static int pstore_write_user_compat(struct pstore_record *record,

				    const char __user *buf)

{

	unsigned long flags = 0;
@@ -662,7 +655,7 @@ static int pstore_write_buf_user_compat(struct pstore_record *record, 
			break;

		}

		record->size = c;

		ret = record->psi->write_buf(record);

		ret = record->psi->write(record);

		if (unlikely(ret < 0))

			break;

		i += c;
@@ -687,6 +680,20 @@ int pstore_register(struct pstore_info *psi) 
		return -EPERM;

	}



	/* Sanity check flags. */

	if (!psi->flags) {

		pr_warn("backend '%s' must support at least one frontend\n",

			psi->name);

		return -EINVAL;

	}



	/* Check for required functions. */

	if (!psi->read || !psi->write) {

		pr_warn("backend '%s' must implement read() and write()\n",

			psi->name);

		return -EINVAL;

	}



	spin_lock(&pstore_lock);

	if (psinfo) {

		pr_warn("backend '%s' already loaded: ignoring '%s'\n",
@@ -695,10 +702,8 @@ int pstore_register(struct pstore_info *psi) 
		return -EBUSY;

	}



	if (!psi->write)

		psi->write = pstore_write_compat;

	if (!psi->write_buf_user)

		psi->write_buf_user = pstore_write_buf_user_compat;

	if (!psi->write_user)

		psi->write_user = pstore_write_user_compat;

	psinfo = psi;

	mutex_init(&psinfo->read_mutex);

	spin_unlock(&pstore_lock);

fs/pstore/pmsg.c

+2 −2
Original line number Diff line number Diff line
@@ -33,12 +33,12 @@ static ssize_t write_pmsg(struct file *file, const char __user *buf, 
	if (!count)

		return 0;



	/* check outside lock, page in any data. write_buf_user also checks */

	/* check outside lock, page in any data. write_user also checks */

	if (!access_ok(VERIFY_READ, buf, count))

		return -EFAULT;



	mutex_lock(&pmsg_lock);

	ret = psinfo->write_buf_user(&record, buf);

	ret = psinfo->write_user(&record, buf);

	mutex_unlock(&pmsg_lock);

	return ret ? ret : count;

}

fs/pstore/ram.c

+5 −5
Original line number Diff line number Diff line
@@ -378,7 +378,7 @@ static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz, 
	return len;

}



static int notrace ramoops_pstore_write_buf(struct pstore_record *record)

static int notrace ramoops_pstore_write(struct pstore_record *record)

{

	struct ramoops_context *cxt = record->psi->data;

	struct persistent_ram_zone *prz;
@@ -451,7 +451,7 @@ static int notrace ramoops_pstore_write_buf(struct pstore_record *record) 
	return 0;

}



static int notrace ramoops_pstore_write_buf_user(struct pstore_record *record,

static int notrace ramoops_pstore_write_user(struct pstore_record *record,

					     const char __user *buf)

{

	if (record->type == PSTORE_TYPE_PMSG) {
@@ -503,8 +503,8 @@ static struct ramoops_context oops_cxt = { 
		.name	= "ramoops",

		.open	= ramoops_pstore_open,

		.read	= ramoops_pstore_read,

		.write_buf	= ramoops_pstore_write_buf,

		.write_buf_user	= ramoops_pstore_write_buf_user,

		.write	= ramoops_pstore_write,

		.write_user	= ramoops_pstore_write_user,

		.erase	= ramoops_pstore_erase,

	},

};

include/linux/pstore.h

+10 −19
Original line number Diff line number Diff line
@@ -130,27 +130,19 @@ struct pstore_record { 
 *	available, or negative on error.

 *

 * @write:

 *	Perform a frontend notification of a write to a backend record. The

 *	data to be stored has already been written to the registered @buf

 *	of the @psi structure.

 *	A newly generated record needs to be written to backend storage.

 *

 *	@record:

 *		pointer to record metadata. Note that @buf is NULL, since

 *		the @buf registered with @psi is what has been written. The

 *		backend is expected to update @id.

 *		pointer to record metadata. When @type is PSTORE_TYPE_DMESG,

 *		@buf will be pointing to the preallocated @psi.buf, since

 *		memory allocation may be broken during an Oops. Regardless,

 *		@buf must be proccesed or copied before returning. The

 *		backend is also expected to write @id with something that

 8		can help identify this record to a future @erase callback.

 *

 *	Returns 0 on success, and non-zero on error.

 *

 * @write_buf:

 *	Perform a frontend write to a backend record. The record contains

 *	all metadata and the buffer to write to backend storage. (Unlike

 *	@write, this does not use the @psi @buf.)

 *

 *	@record:	pointer to record metadata.

 *

 *	Returns 0 on success, and non-zero on error.

 *

 * @write_buf_user:

 * @write_user:

 *	Perform a frontend write to a backend record, using a specified

 *	buffer that is coming directly from userspace, instead of the

 *	@record @buf.
@@ -188,8 +180,7 @@ struct pstore_info { 
	int		(*close)(struct pstore_info *psi);

	ssize_t		(*read)(struct pstore_record *record);

	int		(*write)(struct pstore_record *record);

	int		(*write_buf)(struct pstore_record *record);

	int		(*write_buf_user)(struct pstore_record *record,

	int		(*write_user)(struct pstore_record *record,

				      const char __user *buf);

	int		(*erase)(struct pstore_record *record);

};