Implement ->proc_read_buf() so procfs copies what is read to userspace after it unpinned the entry, and read the config space into procfs' buffer with put_unaligned_le16() and put_unaligned_le32() instead of put_user(). A read into a buffer that can't be written used to report success. It fails with -EFAULT now. A page holds all of the config space, so a single read of it still works, libpci treats a short read as an error.
Signed-off-by: Christian Brauner (Amutable) <[email protected]> --- drivers/pci/proc.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c index d420353ee2b3..a8d7469f222b 100644 --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -29,8 +29,8 @@ static loff_t proc_bus_pci_lseek(struct file *file, loff_t off, int whence) return fixed_size_llseek(file, off, whence, dev->cfg_size); } -static ssize_t proc_bus_pci_read(struct file *file, char __user *buf, - size_t nbytes, loff_t *ppos) +static ssize_t proc_bus_pci_read(struct file *file, char *buf, size_t nbytes, + loff_t *ppos) { struct pci_dev *dev = pde_data(file_inode(file)); unsigned int pos, cnt, size; @@ -60,15 +60,12 @@ static ssize_t proc_bus_pci_read(struct file *file, char __user *buf, nbytes = size - pos; cnt = nbytes; - if (!access_ok(buf, cnt)) - return -EINVAL; - pci_config_pm_runtime_get(dev); if ((pos & 1) && cnt) { unsigned char val; pci_user_read_config_byte(dev, pos, &val); - put_user(val, buf); + *buf = val; buf++; pos++; cnt--; @@ -77,7 +74,7 @@ static ssize_t proc_bus_pci_read(struct file *file, char __user *buf, if ((pos & 3) && cnt > 2) { unsigned short val; pci_user_read_config_word(dev, pos, &val); - put_user(cpu_to_le16(val), (__le16 __user *) buf); + put_unaligned_le16(val, buf); buf += 2; pos += 2; cnt -= 2; @@ -86,7 +83,7 @@ static ssize_t proc_bus_pci_read(struct file *file, char __user *buf, while (cnt >= 4) { unsigned int val; pci_user_read_config_dword(dev, pos, &val); - put_user(cpu_to_le32(val), (__le32 __user *) buf); + put_unaligned_le32(val, buf); buf += 4; pos += 4; cnt -= 4; @@ -96,7 +93,7 @@ static ssize_t proc_bus_pci_read(struct file *file, char __user *buf, if (cnt >= 2) { unsigned short val; pci_user_read_config_word(dev, pos, &val); - put_user(cpu_to_le16(val), (__le16 __user *) buf); + put_unaligned_le16(val, buf); buf += 2; pos += 2; cnt -= 2; @@ -105,7 +102,7 @@ static ssize_t proc_bus_pci_read(struct file *file, char __user *buf, if (cnt) { unsigned char val; pci_user_read_config_byte(dev, pos, &val); - put_user(val, buf); + *buf = val; pos++; } @@ -327,7 +324,7 @@ static int proc_bus_pci_release(struct inode *inode, struct file *file) static const struct proc_ops proc_bus_pci_ops = { .proc_flags = PROC_ENTRY_SHORT_WRITES, .proc_lseek = proc_bus_pci_lseek, - .proc_read = proc_bus_pci_read, + .proc_read_buf = proc_bus_pci_read, .proc_write_buf = proc_bus_pci_write, .proc_write_size = PCI_CFG_SPACE_EXP_SIZE, .proc_ioctl = proc_bus_pci_ioctl, -- 2.53.0
