diff options
author | Jann Horn <jannh@google.com> | 2019-04-10 09:55:48 -0700 |
---|---|---|
committer | Micah Morton <mortonm@chromium.org> | 2019-07-15 08:07:09 -0700 |
commit | 78ae7df96d647627ceae0b65eea9e4f83a0a4b66 (patch) | |
tree | 1f7f4fb2c97ee93390fe7527e4d026ee87214422 /security | |
parent | 8068866c4af124345e2a129be921278aada7830f (diff) |
LSM: SafeSetID: refactor policy parsing
In preparation for changing the policy parsing logic, refactor the line
parsing logic to be less verbose and move it into a separate function.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
Diffstat (limited to 'security')
-rw-r--r-- | security/safesetid/securityfs.c | 84 |
1 files changed, 33 insertions, 51 deletions
diff --git a/security/safesetid/securityfs.c b/security/safesetid/securityfs.c index 2c6c829be044..90784a8d950a 100644 --- a/security/safesetid/securityfs.c +++ b/security/safesetid/securityfs.c @@ -33,68 +33,50 @@ static struct safesetid_file_entry safesetid_files[] = { /* * In the case the input buffer contains one or more invalid UIDs, the kuid_t - * variables pointed to by 'parent' and 'child' will get updated but this + * variables pointed to by @parent and @child will get updated but this * function will return an error. + * Contents of @buf may be modified. */ -static int parse_safesetid_whitelist_policy(const char __user *buf, - size_t len, - kuid_t *parent, - kuid_t *child) +static int parse_policy_line( + struct file *file, char *buf, kuid_t *parent, kuid_t *child) { - char *kern_buf; - char *parent_buf; - char *child_buf; - const char separator[] = ":"; + char *child_str; int ret; - size_t first_substring_length; - long parsed_parent; - long parsed_child; + u32 parsed_parent, parsed_child; - /* Duplicate string from user memory and NULL-terminate */ - kern_buf = memdup_user_nul(buf, len); - if (IS_ERR(kern_buf)) - return PTR_ERR(kern_buf); - - /* - * Format of |buf| string should be <UID>:<UID>. - * Find location of ":" in kern_buf (copied from |buf|). - */ - first_substring_length = strcspn(kern_buf, separator); - if (first_substring_length == 0 || first_substring_length == len) { - ret = -EINVAL; - goto free_kern; - } - - parent_buf = kmemdup_nul(kern_buf, first_substring_length, GFP_KERNEL); - if (!parent_buf) { - ret = -ENOMEM; - goto free_kern; - } + /* Format of |buf| string should be <UID>:<UID>. */ + child_str = strchr(buf, ':'); + if (child_str == NULL) + return -EINVAL; + *child_str = '\0'; + child_str++; - ret = kstrtol(parent_buf, 0, &parsed_parent); + ret = kstrtou32(buf, 0, &parsed_parent); if (ret) - goto free_both; + return ret; - child_buf = kern_buf + first_substring_length + 1; - ret = kstrtol(child_buf, 0, &parsed_child); + ret = kstrtou32(child_str, 0, &parsed_child); if (ret) - goto free_both; + return ret; *parent = make_kuid(current_user_ns(), parsed_parent); - if (!uid_valid(*parent)) { - ret = -EINVAL; - goto free_both; - } - *child = make_kuid(current_user_ns(), parsed_child); - if (!uid_valid(*child)) { - ret = -EINVAL; - goto free_both; - } + if (!uid_valid(*parent) || !uid_valid(*child)) + return -EINVAL; -free_both: - kfree(parent_buf); -free_kern: + return 0; +} + +static int parse_safesetid_whitelist_policy( + struct file *file, const char __user *buf, size_t len, + kuid_t *parent, kuid_t *child) +{ + char *kern_buf = memdup_user_nul(buf, len); + int ret; + + if (IS_ERR(kern_buf)) + return PTR_ERR(kern_buf); + ret = parse_policy_line(file, kern_buf, parent, child); kfree(kern_buf); return ret; } @@ -121,8 +103,8 @@ static ssize_t safesetid_file_write(struct file *file, flush_safesetid_whitelist_entries(); break; case SAFESETID_WHITELIST_ADD: - ret = parse_safesetid_whitelist_policy(buf, len, &parent, - &child); + ret = parse_safesetid_whitelist_policy(file, buf, len, + &parent, &child); if (ret) return ret; |