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authordec05eba <dec05eba@protonmail.com>2024-10-06 22:26:47 +0200
committerdec05eba <dec05eba@protonmail.com>2024-10-06 22:26:47 +0200
commit28ba2e8f3eeee6bd81e5af431d79a612f85e11bf (patch)
tree88aac71c60a641a08336c8b0ecef735bf53a16b2 /kms/client
parent29a21ffff0c1447284957ed3b12a73e12bcdc3fb (diff)
gsr-kms-server 'security': only allow gpu-screen-recorder to get framebuffer
Diffstat (limited to 'kms/client')
-rw-r--r--kms/client/kms_client.c83
1 files changed, 45 insertions, 38 deletions
diff --git a/kms/client/kms_client.c b/kms/client/kms_client.c
index 468e3a6..b72c64b 100644
--- a/kms/client/kms_client.c
+++ b/kms/client/kms_client.c
@@ -146,47 +146,41 @@ static bool create_socket_path(char *output_path, size_t output_path_size) {
return true;
}
-static void string_copy(char *dst, const char *src, int len) {
- int src_len = strlen(src);
- int min_len = src_len;
- if(len - 1 < min_len)
- min_len = len - 1;
- memcpy(dst, src, min_len);
- dst[min_len] = '\0';
-}
-
-static bool find_program_in_path(const char *program_name, char *filepath, int filepath_len) {
- const char *path = getenv("PATH");
- if(!path)
+static bool readlink_realpath(const char *filepath, char *buffer) {
+ char symlinked_path[PATH_MAX];
+ ssize_t bytes_written = readlink(filepath, symlinked_path, sizeof(symlinked_path) - 1);
+ if(bytes_written == -1 && errno == EINVAL) {
+ /* Not a symlink */
+ snprintf(symlinked_path, sizeof(symlinked_path), "%s", filepath);
+ } else if(bytes_written == -1) {
return false;
+ } else {
+ symlinked_path[bytes_written] = '\0';
+ }
- int program_name_len = strlen(program_name);
- const char *end = path + strlen(path);
- while(path != end) {
- const char *part_end = strchr(path, ':');
- const char *next = part_end;
- if(part_end) {
- next = part_end + 1;
- } else {
- part_end = end;
- next = end;
- }
+ if(!realpath(symlinked_path, buffer))
+ return false;
- int len = part_end - path;
- if(len + 1 + program_name_len < filepath_len) {
- memcpy(filepath, path, len);
- filepath[len] = '/';
- memcpy(filepath + len + 1, program_name, program_name_len);
- filepath[len + 1 + program_name_len] = '\0';
+ return true;
+}
- if(access(filepath, F_OK) == 0)
- return true;
- }
+static bool strcat_safe(char *str, int size, const char *str_to_add) {
+ const int str_len = strlen(str);
+ const int str_to_add_len = strlen(str_to_add);
+ if(str_len + str_to_add_len + 1 >= size)
+ return false;
- path = next;
- }
+ memcpy(str + str_len, str_to_add, str_to_add_len);
+ str[str_len + str_to_add_len] = '\0';
+ return true;
+}
- return false;
+static void file_get_directory(char *filepath) {
+ char *end = strrchr(filepath, '/');
+ if(end == NULL)
+ filepath[0] = '\0';
+ else
+ *end = '\0';
}
int gsr_kms_client_init(gsr_kms_client *self, const char *card_path) {
@@ -206,11 +200,24 @@ int gsr_kms_client_init(gsr_kms_client *self, const char *card_path) {
}
char server_filepath[PATH_MAX];
- if(!find_program_in_path("gsr-kms-server", server_filepath, sizeof(server_filepath))) {
- fprintf(stderr, "gsr error: gsr_kms_client_init: gsr-kms-server is not installed\n");
+ if(!readlink_realpath("/proc/self/exe", server_filepath)) {
+ fprintf(stderr, "gsr error: gsr_kms_client_init: failed to resolve /proc/self/exe\n");
+ return -1;
+ }
+ file_get_directory(server_filepath);
+
+ if(!strcat_safe(server_filepath, sizeof(server_filepath), "/gsr-kms-server")) {
+ fprintf(stderr, "gsr error: gsr_kms_client_init: gsr-kms-server path too long\n");
return -1;
}
+ if(access(server_filepath, F_OK) != 0) {
+ fprintf(stderr, "gsr error: gsr_kms_client_init: gsr-kms-server is not installed (%s not found)\n", server_filepath);
+ return -1;
+ }
+
+ fprintf(stderr, "gsr info: gsr_kms_client_init: setting up connection to %s\n", server_filepath);
+
const bool inside_flatpak = getenv("FLATPAK_ID") != NULL;
const char *home = getenv("HOME");
if(!home)
@@ -251,7 +258,7 @@ int gsr_kms_client_init(gsr_kms_client *self, const char *card_path) {
}
local_addr.sun_family = AF_UNIX;
- string_copy(local_addr.sun_path, self->initial_socket_path, sizeof(local_addr.sun_path));
+ snprintf(local_addr.sun_path, sizeof(local_addr.sun_path), "%s", (const char*)self->initial_socket_path);
const mode_t prev_mask = umask(0000);
const int bind_res = bind(self->initial_socket_fd, (struct sockaddr*)&local_addr, sizeof(local_addr.sun_family) + strlen(local_addr.sun_path));