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: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2017-03-05 22:41:10 -08:00
parent fdd0311863
commit 4c9ec21976
5 changed files with 39 additions and 43 deletions

View File

@ -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);

View File

@ -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;
@ -632,15 +632,8 @@ 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,
const char __user *buf)
static int pstore_write_user_compat(struct pstore_record *record,
const char __user *buf)
{
unsigned long flags = 0;
size_t i, bufsize, total_size = record->size;
@ -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);

View File

@ -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;
}

View File

@ -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;
@ -451,8 +451,8 @@ 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,
const char __user *buf)
static int notrace ramoops_pstore_write_user(struct pstore_record *record,
const char __user *buf)
{
if (record->type == PSTORE_TYPE_PMSG) {
struct ramoops_context *cxt = record->psi->data;
@ -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,
},
};

View File

@ -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.
@ -188,9 +180,8 @@ 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,
const char __user *buf);
int (*write_user)(struct pstore_record *record,
const char __user *buf);
int (*erase)(struct pstore_record *record);
};