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bpo-47256: re module, limit the maximum capturing group to 1,073,741,823, increasing the depth of backtracking. #32411

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Merged
serhiy-storchaka merged 5 commits into from Apr 18, 2022
Merged

bpo-47256: re module, limit the maximum capturing group to 1,073,741,823, increasing the depth of backtracking. #32411

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d13b037
1. limit the maximum capturing group to 1,073,741,823
wjssz Apr 16, 2022
8a38ca7
2. further reduce sizeof(SRE(match_context))
wjssz Apr 16, 2022
8cfcab9
3. MARK_(PUSH|POP) macros compute marks size only once
wjssz Apr 16, 2022
11c9ad3
4. remove variable i
wjssz Apr 16, 2022
f811dfc
Fix indentation
wjssz Apr 18, 2022
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4. remove variable i
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@wjssz
wjssz committed Apr 16, 2022
commit 11c9ad3e1a7c06164410380705fa218e22cb8bb2
45 changes: 21 additions & 24 deletions Modules/_sre/sre_lib.h
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Original file line number Diff line number Diff line change
Expand Up @@ -561,7 +561,7 @@ SRE(match)(SRE_STATE* state, const SRE_CODE* pattern, int toplevel)
{
const SRE_CHAR* end = (const SRE_CHAR *)state->end;
Py_ssize_t alloc_pos, ctx_pos = -1;
Py_ssize_t i, ret = 0;
Py_ssize_t ret = 0;
int jump;
unsigned int sigcount=0;

Expand Down Expand Up @@ -610,20 +610,22 @@ SRE(match)(SRE_STATE* state, const SRE_CODE* pattern, int toplevel)
/* <MARK> <gid> */
TRACE(("|%p|%p|MARK %d\n", pattern,
ptr, pattern[0]));
i = pattern[0];
if (i & 1)
state->lastindex = i/2 + 1;
if (i > state->lastmark) {
/* state->lastmark is the highest valid index in the
state->mark array. If it is increased by more than 1,
the intervening marks must be set to NULL to signal
that these marks have not been encountered. */
Py_ssize_t j = state->lastmark + 1;
while (j < i)
state->mark[j++] = NULL;
state->lastmark = i;
{
int i = pattern[0];
if (i & 1)
state->lastindex = i/2 + 1;
if (i > state->lastmark) {
/* state->lastmark is the highest valid index in the
state->mark array. If it is increased by more than 1,
the intervening marks must be set to NULL to signal
that these marks have not been encountered. */
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int j = state->lastmark + 1;
while (j < i)
state->mark[j++] = NULL;
state->lastmark = i;
}
state->mark[i] = ptr;
}
state->mark[i] = ptr;
pattern++;
DISPATCH;

Expand Down Expand Up @@ -1376,9 +1378,8 @@ SRE(match)(SRE_STATE* state, const SRE_CODE* pattern, int toplevel)
/* match backreference */
TRACE(("|%p|%p|GROUPREF %d\n", pattern,
ptr, pattern[0]));
i = pattern[0];
{
Py_ssize_t groupref = i+i;
int groupref = pattern[0] * 2;
if (groupref >= state->lastmark) {
RETURN_FAILURE;
} else {
Expand All @@ -1401,9 +1402,8 @@ SRE(match)(SRE_STATE* state, const SRE_CODE* pattern, int toplevel)
/* match backreference */
TRACE(("|%p|%p|GROUPREF_IGNORE %d\n", pattern,
ptr, pattern[0]));
i = pattern[0];
{
Py_ssize_t groupref = i+i;
int groupref = pattern[0] * 2;
if (groupref >= state->lastmark) {
RETURN_FAILURE;
} else {
Expand All @@ -1427,9 +1427,8 @@ SRE(match)(SRE_STATE* state, const SRE_CODE* pattern, int toplevel)
/* match backreference */
TRACE(("|%p|%p|GROUPREF_UNI_IGNORE %d\n", pattern,
ptr, pattern[0]));
i = pattern[0];
{
Py_ssize_t groupref = i+i;
int groupref = pattern[0] * 2;
if (groupref >= state->lastmark) {
RETURN_FAILURE;
} else {
Expand All @@ -1453,9 +1452,8 @@ SRE(match)(SRE_STATE* state, const SRE_CODE* pattern, int toplevel)
/* match backreference */
TRACE(("|%p|%p|GROUPREF_LOC_IGNORE %d\n", pattern,
ptr, pattern[0]));
i = pattern[0];
{
Py_ssize_t groupref = i+i;
int groupref = pattern[0] * 2;
if (groupref >= state->lastmark) {
RETURN_FAILURE;
} else {
Expand All @@ -1479,9 +1477,8 @@ SRE(match)(SRE_STATE* state, const SRE_CODE* pattern, int toplevel)
TRACE(("|%p|%p|GROUPREF_EXISTS %d\n", pattern,
ptr, pattern[0]));
/* <GROUPREF_EXISTS> <group> <skip> codeyes <JUMP> codeno ... */
i = pattern[0];
{
Py_ssize_t groupref = i+i;
int groupref = pattern[0] * 2;
if (groupref >= state->lastmark) {
pattern += pattern[1];
DISPATCH;
Expand Down