Date: Sun, 31 Jan 2016 08:04:45 -0800 From: Khem Raj <raj.khem@...il.com> To: musl@...ts.openwall.com Subject: Re: [PATCH] regex: increase the stack tre uses for tnfa creation On Sun, Jan 31, 2016 at 7:46 AM, Szabolcs Nagy <nsz@...t70.net> wrote: > 10k elements stack is increased to 1000k, It seems this stack is on heap is that right ? if not then does this enforce some higher minimum limit on stack otherwise tnfa creation fails > for reasonable sized patterns: a single literal char can add 7 elements > to this stack, so regcomp of an 1500 char long pattern (with only litral > chars) fails with REG_ESPACE. (the new limit allows about < 150k chars, > this arbitrary limit allows most command line regex usage.) > > ideally there would be no upper bound: regcomp dynamically reallocates > this buffer, every reallocation checks for allocation failure and at > the end this stack is freed so there is no reason for special bound. > however that may have unwanted effect on regcomp and regexec runtime > so this is a conservative change. > --- > src/regex/regcomp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/src/regex/regcomp.c b/src/regex/regcomp.c > index 7ce2988..da6abd1 100644 > --- a/src/regex/regcomp.c > +++ b/src/regex/regcomp.c > @@ -2688,7 +2688,7 @@ regcomp(regex_t *restrict preg, const char *restrict regex, int cflags) > > /* Allocate a stack used throughout the compilation process for various > purposes. */ > - stack = tre_stack_new(512, 10240, 128); > + stack = tre_stack_new(512, 1024000, 128); > if (!stack) > return REG_ESPACE; > /* Allocate a fast memory allocator. */ > -- > 2.7.0 >
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