Add validate_ipc_target()

1 files changed, 46 insertions, 0 deletions

diff --git a/sway/security.c b/sway/security.c
index 96af2b88..8eab6126 100644
--- a/sway/security.c
+++ b/sway/security.c
@@ -1,4 +1,6 @@
 #define _XOPEN_SOURCE 500
+#include <sys/types.h>
+#include <sys/stat.h>
 #include <string.h>
 #include <unistd.h>
 #include <stdio.h>
@@ -6,8 +8,46 @@
 #include "sway/security.h"
 #include "log.h"
 
+static bool validate_ipc_target(const char *program) {
+        struct stat sb;
+
+        sway_log(L_DEBUG, "Validating IPC target '%s'", program);
+
+        if (!strcmp(program, "*")) {
+                return true;
+        }
+        if (lstat(program, &sb) == -1) {
+                return false;
+        }
+        if (!S_ISREG(sb.st_mode)) {
+                sway_log(L_ERROR,
+                                "IPC target '%s' MUST be/point at an existing regular file",
+                                program);
+                return false;
+        }
+        if (sb.st_uid != 0) {
+#ifdef NDEBUG
+                sway_log(L_ERROR, "IPC target '%s' MUST be owned by root", program);
+                return false;
+#else
+                sway_log(L_INFO, "IPC target '%s' MUST be owned by root (waived for debug build)", program);
+                return true;
+#endif
+        }
+        if (sb.st_mode & S_IWOTH) {
+                sway_log(L_ERROR, "IPC target '%s' MUST NOT be world writable", program);
+                return false;
+        }
+
+        return true;
+}
+
 struct feature_policy *alloc_feature_policy(const char *program) {
         uint32_t default_policy = 0;
+
+        if (!validate_ipc_target(program)) {
+                return NULL;
+        }
         for (int i = 0; i < config->feature_policies->length; ++i) {
                 struct feature_policy *policy = config->feature_policies->items[i];
                 if (strcmp(policy->program, "*") == 0) {
@@ -26,11 +66,16 @@ struct feature_policy *alloc_feature_policy(const char *program) {
                 return NULL;
         }
         policy->features = default_policy;
+
         return policy;
 }
 
 struct ipc_policy *alloc_ipc_policy(const char *program) {
         uint32_t default_policy = 0;
+
+        if (!validate_ipc_target(program)) {
+                return NULL;
+        }
         for (int i = 0; i < config->ipc_policies->length; ++i) {
                 struct ipc_policy *policy = config->ipc_policies->items[i];
                 if (strcmp(policy->program, "*") == 0) {
@@ -49,6 +94,7 @@ struct ipc_policy *alloc_ipc_policy(const char *program) {
                 return NULL;
         }
         policy->features = default_policy;
+
         return policy;
 }