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habanalabs: fix debugfs code 

This fixes multiple things in the habanalabs debugfs code, in particular:

 - mmu_write() was unnecessarily verbose, copying around between multiple
   buffers
 - mmu_write() could write a user-specified, unbounded amount of userspace
   memory into a kernel buffer (out-of-bounds write)
 - multiple debugfs read handlers ignored the user-supplied count,
   potentially corrupting out-of-bounds userspace data
 - hl_device_read() was unnecessarily verbose
 - hl_device_write() could read uninitialized stack memory
 - multiple debugfs read handlers copied terminating null characters to
   userspace

Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Cc: stable@vger.kernel.org
hifive-unleashed-5.2
Jann Horn 2019-05-04 15:56:08 +02:00 committed by Oded Gabbay
parent 2add64ebae
commit 8438846cce
1 changed files with 18 additions and 42 deletions
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60
drivers/misc/habanalabs/debugfs.c
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@ -459,41 +459,31 @@ static ssize_t mmu_write(struct file *file, const char __user *buf,
struct hl_debugfs_entry *entry = s->private;
struct hl_dbg_device_entry *dev_entry = entry->dev_entry;
struct hl_device *hdev = dev_entry->hdev;
char kbuf[MMU_KBUF_SIZE], asid_kbuf[MMU_ASID_BUF_SIZE],
addr_kbuf[MMU_ADDR_BUF_SIZE];
char kbuf[MMU_KBUF_SIZE];
char *c;
ssize_t rc;
if (!hdev->mmu_enable)
return count;
memset(kbuf, 0, sizeof(kbuf));
memset(asid_kbuf, 0, sizeof(asid_kbuf));
memset(addr_kbuf, 0, sizeof(addr_kbuf));
if (count > sizeof(kbuf) - 1)
goto err;
if (copy_from_user(kbuf, buf, count))
goto err;
kbuf[MMU_KBUF_SIZE - 1] = 0;
kbuf[count] = 0;
c = strchr(kbuf, ' ');
if (!c)
goto err;
*c = '\0';
memcpy(asid_kbuf, kbuf, c - kbuf);
rc = kstrtouint(asid_kbuf, 10, &dev_entry->mmu_asid);
rc = kstrtouint(kbuf, 10, &dev_entry->mmu_asid);
if (rc)
goto err;
c = strstr(kbuf, " 0x");
if (!c)
if (strncmp(c+1, "0x", 2))
goto err;
c += 3;
memcpy(addr_kbuf, c, (kbuf + count) - c);
rc = kstrtoull(addr_kbuf, 16, &dev_entry->mmu_addr);
rc = kstrtoull(c+3, 16, &dev_entry->mmu_addr);
if (rc)
goto err;
@ -600,10 +590,8 @@ static ssize_t hl_data_read32(struct file *f, char __user *buf,
}
sprintf(tmp_buf, "0x%08x\n", val);
rc = simple_read_from_buffer(buf, strlen(tmp_buf) + 1, ppos, tmp_buf,
strlen(tmp_buf) + 1);
return rc;
return simple_read_from_buffer(buf, count, ppos, tmp_buf,
strlen(tmp_buf));
}
static ssize_t hl_data_write32(struct file *f, const char __user *buf,
@ -645,7 +633,6 @@ static ssize_t hl_get_power_state(struct file *f, char __user *buf,
struct hl_dbg_device_entry *entry = file_inode(f)->i_private;
struct hl_device *hdev = entry->hdev;
char tmp_buf[200];
ssize_t rc;
int i;
if (*ppos)
@ -660,10 +647,8 @@ static ssize_t hl_get_power_state(struct file *f, char __user *buf,
sprintf(tmp_buf,
"current power state: %d\n1 - D0\n2 - D3hot\n3 - Unknown\n", i);
rc = simple_read_from_buffer(buf, strlen(tmp_buf) + 1, ppos, tmp_buf,
strlen(tmp_buf) + 1);
return rc;
return simple_read_from_buffer(buf, count, ppos, tmp_buf,
strlen(tmp_buf));
}
static ssize_t hl_set_power_state(struct file *f, const char __user *buf,
@ -716,8 +701,8 @@ static ssize_t hl_i2c_data_read(struct file *f, char __user *buf,
}
sprintf(tmp_buf, "0x%02x\n", val);
rc = simple_read_from_buffer(buf, strlen(tmp_buf) + 1, ppos, tmp_buf,
strlen(tmp_buf) + 1);
rc = simple_read_from_buffer(buf, count, ppos, tmp_buf,
strlen(tmp_buf));
return rc;
}
@ -806,18 +791,9 @@ static ssize_t hl_led2_write(struct file *f, const char __user *buf,
static ssize_t hl_device_read(struct file *f, char __user *buf,
size_t count, loff_t *ppos)
{
char tmp_buf[200];
ssize_t rc;
if (*ppos)
return 0;
sprintf(tmp_buf,
"Valid values: disable, enable, suspend, resume, cpu_timeout\n");
rc = simple_read_from_buffer(buf, strlen(tmp_buf) + 1, ppos, tmp_buf,
strlen(tmp_buf) + 1);
return rc;
static const char *help =
"Valid values: disable, enable, suspend, resume, cpu_timeout\n";
return simple_read_from_buffer(buf, count, ppos, help, strlen(help));
}
static ssize_t hl_device_write(struct file *f, const char __user *buf,
@ -825,7 +801,7 @@ static ssize_t hl_device_write(struct file *f, const char __user *buf,
{
struct hl_dbg_device_entry *entry = file_inode(f)->i_private;
struct hl_device *hdev = entry->hdev;
char data[30];
char data[30] = {0};
/* don't allow partial writes */
if (*ppos != 0)