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ACPI / EC: access user space with get_user()/put_user()
User space pointer may not be dereferenced. Use get_user()/put_user() instead and check their return codes. Signed-off-by: Vasiliy Kulikov <[email protected]> Signed-off-by: Thomas Renninger <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]>
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Original file line number | Diff line number | Diff line change |
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@@ -12,6 +12,7 @@ | |
#include <linux/acpi.h> | ||
#include <linux/debugfs.h> | ||
#include <linux/module.h> | ||
#include <linux/uaccess.h> | ||
#include "internal.h" | ||
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MODULE_AUTHOR("Thomas Renninger <[email protected]>"); | ||
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@@ -34,7 +35,6 @@ static ssize_t acpi_ec_read_io(struct file *f, char __user *buf, | |
* struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private; | ||
*/ | ||
unsigned int size = EC_SPACE_SIZE; | ||
u8 *data = (u8 *) buf; | ||
loff_t init_off = *off; | ||
int err = 0; | ||
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@@ -47,9 +47,15 @@ static ssize_t acpi_ec_read_io(struct file *f, char __user *buf, | |
size = count; | ||
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while (size) { | ||
err = ec_read(*off, &data[*off - init_off]); | ||
u8 byte_read; | ||
err = ec_read(*off, &byte_read); | ||
if (err) | ||
return err; | ||
if (put_user(byte_read, buf + *off - init_off)) { | ||
if (*off - init_off) | ||
return *off - init_off; /* partial read */ | ||
return -EFAULT; | ||
} | ||
*off += 1; | ||
size--; | ||
} | ||
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@@ -65,7 +71,6 @@ static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf, | |
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unsigned int size = count; | ||
loff_t init_off = *off; | ||
u8 *data = (u8 *) buf; | ||
int err = 0; | ||
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if (*off >= EC_SPACE_SIZE) | ||
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@@ -76,7 +81,12 @@ static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf, | |
} | ||
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while (size) { | ||
u8 byte_write = data[*off - init_off]; | ||
u8 byte_write; | ||
if (get_user(byte_write, buf + *off - init_off)) { | ||
if (*off - init_off) | ||
return *off - init_off; /* partial write */ | ||
return -EFAULT; | ||
} | ||
err = ec_write(*off, byte_write); | ||
if (err) | ||
return err; | ||
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