Fix m17n backspace handling causes out-of-bounds write in checkType

[CVE-2022-38223]
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1019599
Bug-Debian: https://github.com/tats/w3m/issues/242
This commit is contained in:
Tatsuya Kinoshita
2022-12-20 21:16:48 +09:00
parent c515ea8a47
commit 419ca82d57

22
etc.c
View File

@@ -256,6 +256,9 @@ checkType(Str s, Lineprop **oprop, Linecolor **ocolor)
#ifdef USE_M17N
int i;
int plen = 0, clen;
int *plens = NULL;
static int *plens_buffer = NULL;
static int plens_size = 0;
#endif
if (prop_size < s->length) {
@@ -263,6 +266,13 @@ checkType(Str s, Lineprop **oprop, Linecolor **ocolor)
prop_buffer = New_Reuse(Lineprop, prop_buffer, prop_size);
}
prop = prop_buffer;
#ifdef USE_M17N
if (plens_size < s->length) {
plens_size = (s->length > LINELEN) ? s->length : LINELEN;
plens_buffer = New_Reuse(int, plens_buffer, plens_size);
}
plens = plens_buffer;
#endif
if (ShowEffect) {
bs = memchr(str, '\b', s->length);
@@ -297,14 +307,21 @@ checkType(Str s, Lineprop **oprop, Linecolor **ocolor)
#ifdef USE_ANSI_COLOR
if (color)
*(color++) = 0;
#endif
#ifdef USE_M17N
*(plens++) = plen = 1;
#endif
}
Strcat_charp_n(s, sp, (int)(str - sp));
}
}
if (!do_copy) {
for (; str < endp && IS_ASCII(*str); str++)
for (; str < endp && IS_ASCII(*str); str++) {
*(prop++) = PE_NORMAL | (IS_CNTRL(*str) ? PC_CTRL : PC_ASCII);
#ifdef USE_M17N
*(plens++) = plen = 1;
#endif
}
}
while (str < endp) {
@@ -366,6 +383,7 @@ checkType(Str s, Lineprop **oprop, Linecolor **ocolor)
else {
Strshrink(s, plen);
prop -= plen;
plen = *(--plens);
str += 2;
}
}
@@ -387,6 +405,7 @@ checkType(Str s, Lineprop **oprop, Linecolor **ocolor)
else {
Strshrink(s, plen);
prop -= plen;
plen = *(--plens);
str++;
}
#else
@@ -441,6 +460,7 @@ checkType(Str s, Lineprop **oprop, Linecolor **ocolor)
*(prop++) = mode;
#ifdef USE_M17N
plen = get_mclen(str);
*(plens++) = plen;
if (plen > 1) {
mode = (mode & ~PC_WCHAR1) | PC_WCHAR2;
for (i = 1; i < plen; i++) {