From 8e2174e9bd836e53c8b9c6e00d1bc6e2a718686e Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Sun, 8 Apr 2018 18:06:24 +0200 Subject: [PATCH] wget: check chunk length for overflowing off_t function old new delta retrieve_file_data 428 465 +37 wget_main 2386 2389 +3 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 2/0 up/down: 40/0) Total: 40 bytes Signed-off-by: Denys Vlasenko --- networking/wget.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/networking/wget.c b/networking/wget.c index c9e576e69..2650b5384 100644 --- a/networking/wget.c +++ b/networking/wget.c @@ -801,7 +801,7 @@ static FILE* prepare_ftp_session(FILE **dfpp, struct host_info *target, len_and_ if (ftpcmd("SIZE ", target->path, sfp) == 213) { G.content_len = BB_STRTOOFF(G.wget_buf + 4, NULL, 10); if (G.content_len < 0 || errno) { - bb_error_msg_and_die("SIZE value is garbage"); + bb_error_msg_and_die("bad SIZE value '%s'", G.wget_buf + 4); } G.got_clen = 1; } @@ -965,11 +965,19 @@ static void NOINLINE retrieve_file_data(FILE *dfp) if (!G.chunked) break; - fgets_trim_sanitize(dfp, NULL); /* Eat empty line */ - get_clen: + /* Each chunk ends with "\r\n" - eat it */ fgets_trim_sanitize(dfp, NULL); + get_clen: + /* chunk size format is "HEXNUM[;name[=val]]\r\n" */ + fgets_trim_sanitize(dfp, NULL); + errno = 0; G.content_len = STRTOOFF(G.wget_buf, NULL, 16); - /* FIXME: error check? */ + /* + * Had a bug with inputs like "ffffffff0001f400" + * smashing the heap later. Ensure >= 0. + */ + if (G.content_len < 0 || errno) + bb_error_msg_and_die("bad chunk length '%s'", G.wget_buf); if (G.content_len == 0) break; /* all done! */ G.got_clen = 1;