From c6bf65dc71ba5d1ea6371f2acd2515598f27c15d Mon Sep 17 00:00:00 2001 From: Philipp Eder Date: Mon, 25 Apr 2022 14:11:24 +0200 Subject: [PATCH] FIX: use strlen of previous argv to gain max name --- base/proctitle.c | 36 +++++++++++++++++++++++++++++------- base/pwpolicy.c | 8 ++++---- 2 files changed, 33 insertions(+), 11 deletions(-) diff --git a/base/proctitle.c b/base/proctitle.c index 44e8a6ac6..54e735b2f 100644 --- a/base/proctitle.c +++ b/base/proctitle.c @@ -28,6 +28,7 @@ #include #include /* for strlen, strdup, bzero, strncpy */ #include +#include #undef G_LOG_DOMAIN /** @@ -46,6 +47,7 @@ static char **old_argv; static int old_argc; extern char **environ; void *current_environ = NULL; +static int max_prog_name = 0; /** * @brief Initializes the process setting variables. @@ -56,7 +58,7 @@ void *current_environ = NULL; void proctitle_init (int argc, char **argv) { - int i = 0; + int i; char **envp = environ; #ifndef __FreeBSD__ char *new_progname, *new_progname_full; @@ -67,6 +69,17 @@ proctitle_init (int argc, char **argv) if (argv == NULL) return; + // according to c99 argv is defined as when argc is set it follows program + // parameter. Since we will override on set_proctitle we know that this + // memory is modifiable. + // Everything after that is unsafe and can lead to segmentation faults. + // Therefore we iterate through argv and append strlen to gather the maximum + // safe program name. + for (i = 0; i < argc; i++) + { + max_prog_name += strlen (argv[i]) + 1; + } + i = 0; new_progname = strdup (__progname); #ifndef __FreeBSD__ @@ -103,20 +116,29 @@ static void proctitle_set_args (const char *new_title, va_list args) { char *formatted; + int tmp; if (old_argv == NULL) /* Called setproctitle before initproctitle ? */ return; + if (max_prog_name == 0) + // there may no program name set + return; + // omit previous additional parameter formatted = g_strdup_vprintf (new_title, args); - // _POSIX_PATH_MAX is conservatively defined as 256 so we just assume that - // max size in order to not run into segmentation faults or having to malloc - memset (old_argv[0], 0, 256); - // we omit one to be 0 terminated - memcpy (old_argv[0], formatted, 255); + tmp = strlen (formatted); + if (tmp > max_prog_name) + { + formatted[max_prog_name] = '\0'; + tmp = max_prog_name; + } + + // set display name + memset (old_argv[0], 0, max_prog_name); + memcpy (old_argv[0], formatted, tmp); g_free (formatted); - // omit previous additional parameter if (old_argc > 1) old_argv[1] = NULL; } diff --git a/base/pwpolicy.c b/base/pwpolicy.c index 7782e3992..e8668f41c 100644 --- a/base/pwpolicy.c +++ b/base/pwpolicy.c @@ -145,19 +145,19 @@ is_keyword (char *string, const char *keyword) if (!strncmp (string, keyword, idx)) { tmp = string + idx; - if (tmp - string >= slen) + if (tmp - string > slen) return NULL; // skip optional: if (*tmp == ':') tmp++; + if (tmp - string > slen) + return NULL; for (; tmp - string < slen && g_ascii_isspace (*tmp); tmp++) { // skip whitespace } - // double check - if (tmp - string < slen) - return tmp; + return tmp; } return NULL; }