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selinux: fix sel_read_bool() allocation and error handling 

Switch sel_read_bool() from using get_zeroed_page() and free_page()
to a stack-allocated buffer. This also fixes a memory leak in the
error path when security_get_bool_value() returns an error.

Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Stephen Smalley 2025-09-02 09:11:08 -04:00 committed by Paul Moore
parent f20e70a341
commit 59ffc9beeb
1 changed files with 5 additions and 13 deletions
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18
security/selinux/selinuxfs.c
View File

@ -1203,7 +1203,7 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf,
size_t count, loff_t *ppos) size_t count, loff_t *ppos)
{ {
struct selinux_fs_info *fsi = file_inode(filep)->i_sb->s_fs_info; struct selinux_fs_info *fsi = file_inode(filep)->i_sb->s_fs_info;
char *page = NULL; char buffer[4];
ssize_t length; ssize_t length;
ssize_t ret; ssize_t ret;
int cur_enforcing; int cur_enforcing;
@ -1217,27 +1217,19 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf,
fsi->bool_pending_names[index])) fsi->bool_pending_names[index]))
goto out_unlock; goto out_unlock;
ret = -ENOMEM;
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page)
goto out_unlock;
cur_enforcing = security_get_bool_value(index); cur_enforcing = security_get_bool_value(index);
if (cur_enforcing < 0) { if (cur_enforcing < 0) {
ret = cur_enforcing; ret = cur_enforcing;
goto out_unlock; goto out_unlock;
} }
length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing, length = scnprintf(buffer, sizeof(buffer), "%d %d", !!cur_enforcing,
fsi->bool_pending_values[index]); !!fsi->bool_pending_values[index]);
mutex_unlock(&selinux_state.policy_mutex); mutex_unlock(&selinux_state.policy_mutex);
ret = simple_read_from_buffer(buf, count, ppos, page, length); return simple_read_from_buffer(buf, count, ppos, buffer, length);
out_free:
free_page((unsigned long)page);
return ret;
out_unlock: out_unlock:
mutex_unlock(&selinux_state.policy_mutex); mutex_unlock(&selinux_state.policy_mutex);
goto out_free; return ret;
} }
static ssize_t sel_write_bool(struct file *filep, const char __user *buf, static ssize_t sel_write_bool(struct file *filep, const char __user *buf,