Skip to content

improve bounds checking for line length validation #624

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
metsw24-max wants to merge 1 commit into
base: trunk
Choose a base branch
from
+6 −3
Open

improve bounds checking for line length validation #624

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 6 additions & 3 deletions modules/filters/mod_substitute.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -239,7 +239,9 @@ static apr_status_t do_pattmatch(ap_filter_t *f, apr_bucket *inb,
* are constanting allocing space and copying
* strings.
*/
if (vb.strlen + len + replen > cfg->max_line_length)
if (vb.strlen > cfg->max_line_length
|| len > cfg->max_line_length - vb.strlen
|| replen > cfg->max_line_length - vb.strlen - len)
return APR_ENOMEM;
ap_varbuf_strmemcat(&vb, buff, len);
ap_varbuf_strmemcat(&vb, replacement, replen);
Expand All @@ -251,7 +253,7 @@ static apr_status_t do_pattmatch(ap_filter_t *f, apr_bucket *inb,
* Check if we still have space for this string and
* the replacement string.
*/
if (space_left < len + replen)
if (len > space_left || replen > space_left - len)
return APR_ENOMEM;
space_left -= len + replen;
/*
Expand Down Expand Up @@ -338,7 +340,8 @@ static apr_status_t do_pattmatch(ap_filter_t *f, apr_bucket *inb,
/* Note that the last param in ap_varbuf_regsub below
* must stay positive. If it gets 0, it would mean
* unlimited space available. */
if (vb.strlen + regm[0].rm_so >= cfg->max_line_length)
if (vb.strlen >= cfg->max_line_length
|| (apr_size_t)regm[0].rm_so > cfg->max_line_length - vb.strlen)
return APR_ENOMEM;
/* copy bytes before the match */
if (regm[0].rm_so > 0)
Expand Down