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0120-w: Prevent out-of-bounds reads in print_display_or_interface().

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They occur if disp or tmp reaches host + len: add checks. Also, constify
everything.
This commit is contained in:
Qualys Security Advisory 1970-01-01 00:00:00 +00:00 committed by Craig Small
parent e9172d0484
commit e24804a9de
1 changed files with 9 additions and 9 deletions
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18
w.c
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@ -106,21 +106,22 @@ static void print_host(const char *restrict host, int len, const int fromlen)
/* This routine prints the display part of the host or IPv6 link address interface */
static void print_display_or_interface(const char *restrict host, int len, int restlen)
{
char *disp,*tmp;
const char *const end = host + (len > 0 ? len : 0);
const char *disp, *tmp;
if (restlen <= 0) return; /* not enough space for printing anything */
/* search for a collon (might be a display) */
disp = (char *)host;
while ( (disp < (host + len)) && (*disp != ':') && isprint(*disp) ) disp++;
disp = host;
while ( (disp < end) && (*disp != ':') && isprint(*disp) ) disp++;
/* colon found */
if (*disp == ':') {
if (disp < end && *disp == ':') {
/* detect multiple colons -> IPv6 in the host (not a display) */
tmp = disp+1;
while ( (tmp < (host + len)) && (*tmp != ':') && isprint(*tmp) ) tmp++;
while ( (tmp < end) && (*tmp != ':') && isprint(*tmp) ) tmp++;
if (*tmp != ':') { /* multiple colons not found - it's a display */
if (tmp >= end || *tmp != ':') { /* multiple colons not found - it's a display */
/* number of chars till the end of the input field */
len -= (disp - host);
@ -142,9 +143,9 @@ static void print_display_or_interface(const char *restrict host, int len, int r
} else { /* multiple colons found - it's an IPv6 address */
/* search for % (interface separator in case of IPv6 link address) */
while ( (tmp < (host + len)) && (*tmp != '%') && isprint(*tmp) ) tmp++;
while ( (tmp < end) && (*tmp != '%') && isprint(*tmp) ) tmp++;
if (*tmp == '%') { /* interface separator found */
if (tmp < end && *tmp == '%') { /* interface separator found */
/* number of chars till the end of the input field */
len -= (tmp - host);
@ -163,7 +164,6 @@ static void print_display_or_interface(const char *restrict host, int len, int r
fputc('-', stdout);
}
}
}
}