From 8365a71946bb1075f5e0e6357fe0f0b92404d966 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 24 Dec 2015 00:08:06 -0500 Subject: selinuxfs: switch to memdup_user_nul() Nothing in there gives a damn about the buffer alignment - it just parses its contents. So the use of get_zeroed_page() doesn't buy us anything - might as well had been kmalloc(), which makes that code equivalent to open-coded memdup_user_nul() Signed-off-by: Al Viro --- security/selinux/selinuxfs.c | 114 ++++++++++++++++--------------------------- 1 file changed, 41 insertions(+), 73 deletions(-) (limited to 'security') diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index c02da25d7b63..73c60baa90a4 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -147,23 +147,16 @@ static ssize_t sel_write_enforce(struct file *file, const char __user *buf, ssize_t length; int new_value; - length = -ENOMEM; if (count >= PAGE_SIZE) - goto out; + return -ENOMEM; /* No partial writes. */ - length = -EINVAL; if (*ppos != 0) - goto out; - - length = -ENOMEM; - page = (char *)get_zeroed_page(GFP_KERNEL); - if (!page) - goto out; + return -EINVAL; - length = -EFAULT; - if (copy_from_user(page, buf, count)) - goto out; + page = memdup_user_nul(buf, count); + if (IS_ERR(page)) + return PTR_ERR(page); length = -EINVAL; if (sscanf(page, "%d", &new_value) != 1) @@ -186,7 +179,7 @@ static ssize_t sel_write_enforce(struct file *file, const char __user *buf, } length = count; out: - free_page((unsigned long) page); + kfree(page); return length; } #else @@ -275,27 +268,20 @@ static ssize_t sel_write_disable(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - char *page = NULL; + char *page; ssize_t length; int new_value; - length = -ENOMEM; if (count >= PAGE_SIZE) - goto out; + return -ENOMEM; /* No partial writes. */ - length = -EINVAL; if (*ppos != 0) - goto out; - - length = -ENOMEM; - page = (char *)get_zeroed_page(GFP_KERNEL); - if (!page) - goto out; + return -EINVAL; - length = -EFAULT; - if (copy_from_user(page, buf, count)) - goto out; + page = memdup_user_nul(buf, count); + if (IS_ERR(page)) + return PTR_ERR(page); length = -EINVAL; if (sscanf(page, "%d", &new_value) != 1) @@ -313,7 +299,7 @@ static ssize_t sel_write_disable(struct file *file, const char __user *buf, length = count; out: - free_page((unsigned long) page); + kfree(page); return length; } #else @@ -611,31 +597,24 @@ static ssize_t sel_read_checkreqprot(struct file *filp, char __user *buf, static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - char *page = NULL; + char *page; ssize_t length; unsigned int new_value; length = task_has_security(current, SECURITY__SETCHECKREQPROT); if (length) - goto out; + return length; - length = -ENOMEM; if (count >= PAGE_SIZE) - goto out; + return -ENOMEM; /* No partial writes. */ - length = -EINVAL; if (*ppos != 0) - goto out; - - length = -ENOMEM; - page = (char *)get_zeroed_page(GFP_KERNEL); - if (!page) - goto out; + return -EINVAL; - length = -EFAULT; - if (copy_from_user(page, buf, count)) - goto out; + page = memdup_user_nul(buf, count); + if (IS_ERR(page)) + return PTR_ERR(page); length = -EINVAL; if (sscanf(page, "%u", &new_value) != 1) @@ -644,7 +623,7 @@ static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf, selinux_checkreqprot = new_value ? 1 : 0; length = count; out: - free_page((unsigned long) page); + kfree(page); return length; } static const struct file_operations sel_checkreqprot_ops = { @@ -1100,14 +1079,12 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf, if (*ppos != 0) goto out; - length = -ENOMEM; - page = (char *)get_zeroed_page(GFP_KERNEL); - if (!page) - goto out; - - length = -EFAULT; - if (copy_from_user(page, buf, count)) + page = memdup_user_nul(buf, count); + if (IS_ERR(page)) { + length = PTR_ERR(page); + page = NULL; goto out; + } length = -EINVAL; if (sscanf(page, "%d", &new_value) != 1) @@ -1121,7 +1098,7 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf, out: mutex_unlock(&sel_mutex); - free_page((unsigned long) page); + kfree(page); return length; } @@ -1154,14 +1131,12 @@ static ssize_t sel_commit_bools_write(struct file *filep, if (*ppos != 0) goto out; - length = -ENOMEM; - page = (char *)get_zeroed_page(GFP_KERNEL); - if (!page) - goto out; - - length = -EFAULT; - if (copy_from_user(page, buf, count)) + page = memdup_user_nul(buf, count); + if (IS_ERR(page)) { + length = PTR_ERR(page); + page = NULL; goto out; + } length = -EINVAL; if (sscanf(page, "%d", &new_value) != 1) @@ -1176,7 +1151,7 @@ static ssize_t sel_commit_bools_write(struct file *filep, out: mutex_unlock(&sel_mutex); - free_page((unsigned long) page); + kfree(page); return length; } @@ -1292,31 +1267,24 @@ static ssize_t sel_write_avc_cache_threshold(struct file *file, size_t count, loff_t *ppos) { - char *page = NULL; + char *page; ssize_t ret; int new_value; ret = task_has_security(current, SECURITY__SETSECPARAM); if (ret) - goto out; + return ret; - ret = -ENOMEM; if (count >= PAGE_SIZE) - goto out; + return -ENOMEM; /* No partial writes. */ - ret = -EINVAL; if (*ppos != 0) - goto out; - - ret = -ENOMEM; - page = (char *)get_zeroed_page(GFP_KERNEL); - if (!page) - goto out; + return -EINVAL; - ret = -EFAULT; - if (copy_from_user(page, buf, count)) - goto out; + page = memdup_user_nul(buf, count); + if (IS_ERR(page)) + return PTR_ERR(page); ret = -EINVAL; if (sscanf(page, "%u", &new_value) != 1) @@ -1326,7 +1294,7 @@ static ssize_t sel_write_avc_cache_threshold(struct file *file, ret = count; out: - free_page((unsigned long)page); + kfree(page); return ret; } -- cgit v1.2.3