commit 0ab8b7c0f22bd45d7108ce0185e027cd8e469593 Author: Robert Ransom <rransom.8774@gmail.com> Date: Fri Feb 4 05:50:44 2011 -0800 Thou shalt not overflow even stupidly small buffers --- src/common/log.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) diff --git a/src/common/log.c b/src/common/log.c index f58b05b..4b21fd9 100644 --- a/src/common/log.c +++ b/src/common/log.c @@ -223,21 +223,31 @@ format_msg(char *buf, size_t buf_len, size_t n; int r; char *end_of_prefix; + char *buf_end; assert(buf_len >= 16); /* prevent integer underflow and general stupidity */ buf_len -= 2; /* subtract 2 characters so we have room for \n\0 */ + buf_end = buf+buf_len; /* point *after* the last char we can write to */ n = _log_prefix(buf, buf_len, severity); end_of_prefix = buf+n; if (log_domains_are_logged) { char *cp = buf+n; + if (cp == buf_end) goto format_msg_no_room_for_domains; *cp++ = '{'; + if (cp == buf_end) goto format_msg_no_room_for_domains; cp = domain_to_string(domain, cp, (buf+buf_len-cp)); + if (cp == buf_end) goto format_msg_no_room_for_domains; *cp++ = '}'; + if (cp == buf_end) goto format_msg_no_room_for_domains; *cp++ = ' '; + if (cp == buf_end) goto format_msg_no_room_for_domains; end_of_prefix = cp; n = cp-buf; + format_msg_no_room_for_domains: + /* This will leave end_of_prefix and n unchanged, and thus cause + * whatever log domain string we had written to be clobbered. */ } if (funcname && should_log_function_name(domain, severity)) {