Messages in this thread | | | From | Oded Gabbay <> | Date | Mon, 6 May 2019 13:15:36 +0300 | Subject | Re: [PATCH] habanalabs: fix debugfs code |
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On Sat, May 4, 2019 at 4:56 PM Jann Horn <jannh@google.com> wrote: > > 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> > --- > compile-tested only, so you might want to test this before applying the > patch > > drivers/misc/habanalabs/debugfs.c | 60 ++++++++++--------------------- > 1 file changed, 18 insertions(+), 42 deletions(-) > > diff --git a/drivers/misc/habanalabs/debugfs.c b/drivers/misc/habanalabs/debugfs.c > index 974a87789bd86..17ba26422b297 100644 > --- a/drivers/misc/habanalabs/debugfs.c > +++ b/drivers/misc/habanalabs/debugfs.c > @@ -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; > > @@ -525,10 +515,8 @@ 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, > @@ -559,7 +547,6 @@ 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) > @@ -574,10 +561,8 @@ 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, > @@ -630,8 +615,8 @@ 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; > } > @@ -720,18 +705,9 @@ 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, > @@ -739,7 +715,7 @@ 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) > -- > 2.21.0.1020.gf2820cf01a-goog >
Thanks! Will be applied to my -next branch
This patch is: Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
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