From: Mark Langsdorf mlangsdo@redhat.com
mainline inclusion from mainline-v5.13-rc1 commit e483bb9a991bdae29a0caa4b3a6d002c968f94aa category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5LBE7 CVE: NA
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In cm_write(), buf is always freed when reaching the end of the function. If the requested count is less than table.length, the allocated buffer will be freed but subsequent calls to cm_write() will still try to access it.
Remove the unconditional kfree(buf) at the end of the function and set the buf to NULL in the -EINVAL error path to match the rest of function.
Fixes: 03d1571d9513 ("ACPI: custom_method: fix memory leaks") Signed-off-by: Mark Langsdorf mlangsdo@redhat.com Cc: 5.4+ stable@vger.kernel.org # 5.4+ Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Xiongfeng Wang wangxiongfeng2@huawei.com Reviewed-by: Hanjun Guo guohanjun@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- drivers/acpi/custom_method.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index 1ed6d24ae1c9..613041870872 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -52,6 +52,7 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, (*ppos + count < count) || (count > uncopied_bytes)) { kfree(buf); + buf = NULL; return -EINVAL; }
@@ -73,7 +74,6 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE); }
- kfree(buf); return count; }