Issue #18684: Fixed reading out of the buffer in the re module.
diff --git a/Modules/_sre.c b/Modules/_sre.c
index 300d883..d6fcda1 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -883,7 +883,7 @@
}
if (state.start == state.ptr) {
- if (last == state.end)
+ if (last == state.end || state.ptr == state.end)
break;
/* skip one character */
state.start = (void*) ((char*) state.ptr + state.charsize);
@@ -1081,6 +1081,8 @@
next:
/* move on */
+ if (state.ptr == state.end)
+ break;
if (state.ptr == state.start)
state.start = (void*) ((char*) state.ptr + state.charsize);
else
@@ -2567,6 +2569,9 @@
PyObject* match;
Py_ssize_t status;
+ if (state->start == NULL)
+ Py_RETURN_NONE;
+
state_reset(state);
state->ptr = state->start;
@@ -2578,10 +2583,14 @@
match = pattern_new_match((PatternObject*) self->pattern,
state, status);
- if (status == 0 || state->ptr == state->start)
+ if (status == 0)
+ state->start = NULL;
+ else if (state->ptr != state->start)
+ state->start = state->ptr;
+ else if (state->ptr != state->end)
state->start = (void*) ((char*) state->ptr + state->charsize);
else
- state->start = state->ptr;
+ state->start = NULL;
return match;
}
@@ -2594,6 +2603,9 @@
PyObject* match;
Py_ssize_t status;
+ if (state->start == NULL)
+ Py_RETURN_NONE;
+
state_reset(state);
state->ptr = state->start;
@@ -2605,10 +2617,14 @@
match = pattern_new_match((PatternObject*) self->pattern,
state, status);
- if (status == 0 || state->ptr == state->start)
+ if (status == 0)
+ state->start = NULL;
+ else if (state->ptr != state->start)
+ state->start = state->ptr;
+ else if (state->ptr != state->end)
state->start = (void*) ((char*) state->ptr + state->charsize);
else
- state->start = state->ptr;
+ state->start = NULL;
return match;
}
diff --git a/Modules/sre_lib.h b/Modules/sre_lib.h
index 5c6c5a5..1049de4 100644
--- a/Modules/sre_lib.h
+++ b/Modules/sre_lib.h
@@ -30,7 +30,7 @@
SRE_IS_LINEBREAK((int) ptr[-1]));
case SRE_AT_END:
- return (((void*) (ptr+1) == state->end &&
+ return (((SRE_CHAR *)state->end - ptr == 1 &&
SRE_IS_LINEBREAK((int) ptr[0])) ||
((void*) ptr == state->end));
@@ -1093,9 +1093,9 @@
/* <ASSERT> <skip> <back> <pattern> */
TRACE(("|%p|%p|ASSERT %d\n", ctx->pattern,
ctx->ptr, ctx->pattern[1]));
- state->ptr = ctx->ptr - ctx->pattern[1];
- if (state->ptr < state->beginning)
+ if (ctx->ptr - (SRE_CHAR *)state->beginning < (Py_ssize_t)ctx->pattern[1])
RETURN_FAILURE;
+ state->ptr = ctx->ptr - ctx->pattern[1];
DO_JUMP0(JUMP_ASSERT, jump_assert, ctx->pattern+2);
RETURN_ON_FAILURE(ret);
ctx->pattern += ctx->pattern[0];
@@ -1106,8 +1106,8 @@
/* <ASSERT_NOT> <skip> <back> <pattern> */
TRACE(("|%p|%p|ASSERT_NOT %d\n", ctx->pattern,
ctx->ptr, ctx->pattern[1]));
- state->ptr = ctx->ptr - ctx->pattern[1];
- if (state->ptr >= state->beginning) {
+ if (ctx->ptr - (SRE_CHAR *)state->beginning >= (Py_ssize_t)ctx->pattern[1]) {
+ state->ptr = ctx->ptr - ctx->pattern[1];
DO_JUMP0(JUMP_ASSERT_NOT, jump_assert_not, ctx->pattern+2);
if (ret) {
RETURN_ON_ERROR(ret);
@@ -1199,12 +1199,20 @@
SRE_CODE* overlap = NULL;
int flags = 0;
+ if (ptr > end)
+ return 0;
+
if (pattern[0] == SRE_OP_INFO) {
/* optimization info block */
/* <INFO> <1=skip> <2=flags> <3=min> <4=max> <5=prefix info> */
flags = pattern[2];
+ if (pattern[3] && end - ptr < (Py_ssize_t)pattern[3]) {
+ TRACE(("reject (got %u chars, need %u)\n",
+ (unsigned int)(end - ptr), pattern[3]));
+ return 0;
+ }
if (pattern[3] > 1) {
/* adjust end point (but make sure we leave at least one
character in there, so literal search will work) */
@@ -1322,15 +1330,18 @@
break;
ptr++;
}
- } else
+ } else {
/* general case */
- while (ptr <= end) {
+ assert(ptr <= end);
+ while (1) {
TRACE(("|%p|%p|SEARCH\n", pattern, ptr));
- state->start = state->ptr = ptr++;
+ state->start = state->ptr = ptr;
status = SRE(match)(state, pattern, 0);
- if (status != 0)
+ if (status != 0 || ptr >= end)
break;
+ ptr++;
}
+ }
return status;
}