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Refactor to avoid picky compiler warnings. Fixes oss-fuzz issue 1454.

This commit is contained in:
Philip.Hazel 2017-05-10 16:44:33 +00:00
parent 3813b518ce
commit 1909bf0691
2 changed files with 28 additions and 17 deletions
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5
ChangeLog
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@ -36,6 +36,10 @@ bugs were never in fully released code, but are noted here for the record.
(e) Mark values were not being passed out of recursions.
(f) Refactor some code in do_callout() to avoid picky compiler warnings about
negative indices. Fixes oss-fuzz issue 1454.
2. Now that pcre2_match() no longer uses recursive function calls (see above),
the "match limit recursion" value seems misnamed. It still exists, and limits
the depth of tree that is searched. To avoid future confusion, it has been
@ -157,6 +161,7 @@ tests to improve coverage.
pcre2test, a crash could occur.
Version 10.23 14-February-2017
------------------------------

38
src/pcre2_match.c
View File

@ -263,18 +263,32 @@ Returns: the return from the callout
static int
do_callout(heapframe *F, match_block *mb, PCRE2_SIZE *lengthptr)
{
PCRE2_SIZE save0, save1;
pcre2_callout_block cb;
int rc;
PCRE2_SIZE save0, save1;
PCRE2_SIZE *callout_ovector;
pcre2_callout_block cb;
*lengthptr = (*Fecode == OP_CALLOUT)?
PRIV(OP_lengths)[OP_CALLOUT] : GET(Fecode, 1 + 2*LINK_SIZE);
if (mb->callout == NULL) return 0; /* No callout function provided */
/* The original matching code (pre 10.30) worked directly with the ovector
passed by the user, and this was passed to callouts. Now that the working
ovector is in the backtracking frame, it no longer needs to reserve space for
the overall match offsets (which would waste space in the frame). For backward
compatibility, however, we pass capture_top and offset_vector to the callout as
if for the extended ovector, and we ensure that the first two slots are unset
by preserving and restoring their current contents. Picky compilers complain if
references such as Fovector[-2] are use directly, so we set up a separate
pointer. */
callout_ovector = (PCRE2_SIZE *)(Fovector) - 2;
cb.version = 1;
cb.capture_top = (uint32_t)Foffset_top/2 + 1;
cb.capture_last = Fcapture_last;
cb.offset_vector = Fovector - 2;
cb.offset_vector = callout_ovector;
cb.mark = mb->nomatch_mark;
cb.subject = mb->start_subject;
cb.subject_length = (PCRE2_SIZE)(mb->end_subject - mb->start_subject);
@ -299,20 +313,12 @@ else /* String callout */
*lengthptr - (1 + 4*LINK_SIZE) - 2;
}
/* The original matching code (pre 10.30) worked directly with the ovector
passed by the user, and this was passed to callouts. Now that the working
ovector is in the backtracking frame, it no longer needs to reserve space for
the overall match offsets (which would waste space in the frame). For backward
compatibility, however, we pass capture_top and offset_vector to the callout as
if for the extended ovector, and we ensure that the first two slots are unset
by preserving and restoring their current contents. */
save0 = Fovector[-2];
save1 = Fovector[-1];
Fovector[-2] = Fovector[-1] = PCRE2_UNSET;
save0 = callout_ovector[0];
save1 = callout_ovector[1];
callout_ovector[0] = callout_ovector[1] = PCRE2_UNSET;
rc = mb->callout(&cb, mb->callout_data);
Fovector[-2] = save0;
Fovector[-1] = save1;
callout_ovector[0] = save0;
callout_ovector[1] = save1;
return rc;
}