From: Ross Zwisler Date: Thu, 7 Dec 2017 21:35:03 +0000 (-0700) Subject: build: fix Wlog_Error_String overflow issues X-Git-Tag: v2022.05.01~1741 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d79448aefec98fbc32b1ec0bcf30a2dd3c122be1;p=users%2Fhch%2Fxfstests-dev.git build: fix Wlog_Error_String overflow issues The 'Wlog_Error_String' string is defined to be 256 bytes in length, but in two places we write into it with a format that contains a string (wfile->w_file) that has length 1024. This can overflow Wlog_Error_String, as we see in the new compiler warnings from gcc 7.2.1: write_log.c:124:37: warning: ‘%s’ directive writing up to 1023 bytes into a region of size 224 [-Wformat-overflow=] "Could not open write_log - open(%s, %#o, %#o) failed: %s\n", ^~ Fix this by increasing the length of Wlog_Error_String to 1280 characters (1024 for wfile->w_file plus 256 for the rest of the format string), and by using snprintf() instead of sprintf() so we are sure we don't overflow. Signed-off-by: Ross Zwisler Reviewed-by: Eryu Guan Signed-off-by: Eryu Guan --- diff --git a/lib/write_log.c b/lib/write_log.c index 8c921fc54..3bfa8c7b3 100644 --- a/lib/write_log.c +++ b/lib/write_log.c @@ -73,7 +73,8 @@ /*#define PATH_MAX pathconf("/", _PC_PATH_MAX)*/ #endif -char Wlog_Error_String[256]; +#define ERROR_STRING_LEN 1280 +char Wlog_Error_String[ERROR_STRING_LEN]; #if __STDC__ static int wlog_rec_pack(struct wlog_rec *wrec, char *buf, int flag); @@ -120,7 +121,7 @@ int mode; umask(omask); if (wfile->w_afd == -1) { - sprintf(Wlog_Error_String, + snprintf(Wlog_Error_String, ERROR_STRING_LEN, "Could not open write_log - open(%s, %#o, %#o) failed: %s\n", wfile->w_file, oflags, mode, strerror(errno)); return -1; @@ -132,7 +133,7 @@ int mode; oflags = O_RDWR; if ((wfile->w_rfd = open(wfile->w_file, oflags)) == -1) { - sprintf(Wlog_Error_String, + snprintf(Wlog_Error_String, ERROR_STRING_LEN, "Could not open write log - open(%s, %#o) failed: %s\n", wfile->w_file, oflags, strerror(errno)); close(wfile->w_afd);