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Fix "internal error" bug caused by patterns like "((?2){0,1999}())?".

This commit is contained in:
Philip.Hazel 2015-02-28 11:31:51 +00:00
parent 67800ba810
commit ea03932668
4 changed files with 55 additions and 33 deletions
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8
ChangeLog
View File

@ -97,6 +97,14 @@ only on Windows.
21. "make distclean" was not removing config.h, a file that is created for use
with CMake.
22. A pattern such as "((?2){0,1999}())?", which has a group containing a
forward reference repeated a large (but limited) number of times within a
repeated outer group that has a zero minimum quantifier, caused incorrect code
to be compiled, leading to the error "internal error: previously-checked
referenced subpattern not found" when an incorrect memory address was read.
This bug was reported as "heap overflow", discovered by Kai Lu of Fortinet's
FortiGuard Labs.
Version 10.00 05-January-2015
-----------------------------

72
src/pcre2_compile.c
View File

@ -2586,18 +2586,18 @@ the current group is on this list, it adjusts the offset in the list, not the
value in the reference (which is a group number).
Arguments:
group points to the start of the group
adjust the amount by which the group is to be moved
utf TRUE in UTF mode
cb compile data
save_hwm the hwm forward reference pointer at the start of the group
group points to the start of the group
adjust the amount by which the group is to be moved
utf TRUE in UTF mode
cb compile data
save_hwm_offset the hwm forward reference offset at the start of the group
Returns: nothing
*/
static void
adjust_recurse(PCRE2_UCHAR *group, int adjust, BOOL utf, compile_block *cb,
PCRE2_UCHAR *save_hwm)
size_t save_hwm_offset)
{
PCRE2_UCHAR *ptr = group;
@ -2609,7 +2609,8 @@ while ((ptr = (PCRE2_UCHAR *)find_recurse(ptr, utf)) != NULL)
/* See if this recursion is on the forward reference list. If so, adjust the
reference. */
for (hc = save_hwm; hc < cb->hwm; hc += LINK_SIZE)
for (hc = (PCRE2_UCHAR *)cb->start_workspace + save_hwm_offset; hc < cb->hwm;
hc += LINK_SIZE)
{
offset = (int)GET(hc, 0);
if (cb->start_code + offset == ptr + 1)
@ -3093,7 +3094,7 @@ PCRE2_SPTR tempptr;
PCRE2_SPTR nestptr = NULL;
PCRE2_UCHAR *previous = NULL;
PCRE2_UCHAR *previous_callout = NULL;
PCRE2_UCHAR *save_hwm = NULL;
size_t save_hwm_offset = 0;
uint8_t classbits[32];
/* We can fish out the UTF setting once and for all into a BOOL, but we must
@ -4565,7 +4566,7 @@ for (;; ptr++)
if (repeat_max <= 1) /* Covers 0, 1, and unlimited */
{
*code = OP_END;
adjust_recurse(previous, 1, utf, cb, save_hwm);
adjust_recurse(previous, 1, utf, cb, save_hwm_offset);
memmove(previous + 1, previous, CU2BYTES(len));
code++;
if (repeat_max == 0)
@ -4589,7 +4590,7 @@ for (;; ptr++)
{
int offset;
*code = OP_END;
adjust_recurse(previous, 2 + LINK_SIZE, utf, cb, save_hwm);
adjust_recurse(previous, 2 + LINK_SIZE, utf, cb, save_hwm_offset);
memmove(previous + 2 + LINK_SIZE, previous, CU2BYTES(len));
code += 2 + LINK_SIZE;
*previous++ = OP_BRAZERO + repeat_type;
@ -4652,26 +4653,25 @@ for (;; ptr++)
for (i = 1; i < repeat_min; i++)
{
PCRE2_UCHAR *hc;
PCRE2_UCHAR *this_hwm = cb->hwm;
size_t this_hwm_offset = cb->hwm - cb->start_workspace;
memcpy(code, previous, CU2BYTES(len));
while (cb->hwm > cb->start_workspace + cb->workspace_size -
WORK_SIZE_SAFETY_MARGIN - (this_hwm - save_hwm))
WORK_SIZE_SAFETY_MARGIN -
(this_hwm_offset - save_hwm_offset))
{
size_t save_offset = save_hwm - cb->start_workspace;
size_t this_offset = this_hwm - cb->start_workspace;
*errorcodeptr = expand_workspace(cb);
if (*errorcodeptr != 0) goto FAILED;
save_hwm = (PCRE2_UCHAR *)cb->start_workspace + save_offset;
this_hwm = (PCRE2_UCHAR *)cb->start_workspace + this_offset;
}
for (hc = save_hwm; hc < this_hwm; hc += LINK_SIZE)
for (hc = (PCRE2_UCHAR *)cb->start_workspace + save_hwm_offset;
hc < (PCRE2_UCHAR *)cb->start_workspace + this_hwm_offset;
hc += LINK_SIZE)
{
PUT(cb->hwm, 0, GET(hc, 0) + len);
cb->hwm += LINK_SIZE;
}
save_hwm = this_hwm;
save_hwm_offset = this_hwm_offset;
code += len;
}
}
@ -4716,7 +4716,7 @@ for (;; ptr++)
else for (i = repeat_max - 1; i >= 0; i--)
{
PCRE2_UCHAR *hc;
PCRE2_UCHAR *this_hwm = cb->hwm;
size_t this_hwm_offset = cb->hwm - cb->start_workspace;
*code++ = OP_BRAZERO + repeat_type;
@ -4738,22 +4738,21 @@ for (;; ptr++)
copying them. */
while (cb->hwm > cb->start_workspace + cb->workspace_size -
WORK_SIZE_SAFETY_MARGIN - (this_hwm - save_hwm))
WORK_SIZE_SAFETY_MARGIN -
(this_hwm_offset - save_hwm_offset))
{
size_t save_offset = save_hwm - cb->start_workspace;
size_t this_offset = this_hwm - cb->start_workspace;
*errorcodeptr = expand_workspace(cb);
if (*errorcodeptr != 0) goto FAILED;
save_hwm = (PCRE2_UCHAR *)cb->start_workspace + save_offset;
this_hwm = (PCRE2_UCHAR *)cb->start_workspace + this_offset;
}
for (hc = save_hwm; hc < this_hwm; hc += LINK_SIZE)
for (hc = (PCRE2_UCHAR *)cb->start_workspace + save_hwm_offset;
hc < (PCRE2_UCHAR *)cb->start_workspace + this_hwm_offset;
hc += LINK_SIZE)
{
PUT(cb->hwm, 0, GET(hc, 0) + len + ((i != 0)? 2+LINK_SIZE : 1));
cb->hwm += LINK_SIZE;
}
save_hwm = this_hwm;
save_hwm_offset = this_hwm_offset;
code += len;
}
@ -4849,7 +4848,7 @@ for (;; ptr++)
{
int nlen = (int)(code - bracode);
*code = OP_END;
adjust_recurse(bracode, 1 + LINK_SIZE, utf, cb, save_hwm);
adjust_recurse(bracode, 1 + LINK_SIZE, utf, cb, save_hwm_offset);
memmove(bracode + 1 + LINK_SIZE, bracode, CU2BYTES(nlen));
code += 1 + LINK_SIZE;
nlen += 1 + LINK_SIZE;
@ -4984,7 +4983,7 @@ for (;; ptr++)
else
{
*code = OP_END;
adjust_recurse(tempcode, 1 + LINK_SIZE, utf, cb, save_hwm);
adjust_recurse(tempcode, 1 + LINK_SIZE, utf, cb, save_hwm_offset);
memmove(tempcode + 1 + LINK_SIZE, tempcode, CU2BYTES(len));
code += 1 + LINK_SIZE;
len += 1 + LINK_SIZE;
@ -5009,13 +5008,17 @@ for (;; ptr++)
/* ===================================================================*/
/* Start of nested parenthesized sub-expression, or comment or lookahead or
lookbehind or option setting or condition or all the other extended
parenthesis forms. */
parenthesis forms. We must save the current high-water-mark for the
forward reference list so that we know where they start for this group.
However, because the list may be extended when there are very many forward
references (usually the result of a replicated inner group), we must use
an offset rather than an absolute address. */
case CHAR_LEFT_PARENTHESIS:
newoptions = options;
skipbytes = 0;
bravalue = OP_CBRA;
save_hwm = cb->hwm;
save_hwm_offset = cb->hwm - cb->start_workspace;
reset_bracount = FALSE;
/* First deal with various "verbs" that can be introduced by '*'. */
@ -5972,7 +5975,8 @@ for (;; ptr++)
/* Fudge the value of "called" so that when it is inserted as an
offset below, what it actually inserted is the reference number
of the group. Then remember the forward reference. */
of the group. Then remember the forward reference, expanding the
working space where the list is kept if necessary. */
called = cb->start_code + recno;
if (cb->hwm >= cb->start_workspace + cb->workspace_size -
@ -6395,7 +6399,9 @@ for (;; ptr++)
PCRE2_SPTR p;
uint32_t cf;
save_hwm = cb->hwm; /* Normally this is set when '(' is read */
/* Normally save_hwm_offset is set when '(' is read */
save_hwm_offset = cb->hwm - cb->start_workspace;
terminator = (*(++ptr) == CHAR_LESS_THAN_SIGN)?
CHAR_GREATER_THAN_SIGN : CHAR_APOSTROPHE;
@ -6933,7 +6939,7 @@ for (;;)
{
*code = OP_END;
adjust_recurse(start_bracket, 1 + LINK_SIZE,
(options & PCRE2_UTF) != 0, cb, cb->hwm);
(options & PCRE2_UTF) != 0, cb, cb->hwm - cb->start_workspace);
memmove(start_bracket + 1 + LINK_SIZE, start_bracket,
CU2BYTES(code - start_bracket));
*start_bracket = OP_ONCE;

4
testdata/testinput2 vendored
View File

@ -4171,5 +4171,9 @@ a random value. /Ix
'^(?:a)*+(\w)'
g
g\=ovector=1
# This pattern showed up a compile-time bug
"((?2){0,1999}())?"
# End of testinput2

4
testdata/testoutput2 vendored
View File

@ -13949,5 +13949,9 @@ Matched, but too many substrings
g\=ovector=1
Matched, but too many substrings
0: g
# This pattern showed up a compile-time bug
"((?2){0,1999}())?"
# End of testinput2