Hi Ben, On Fri, Feb 02, 2018 at 11:16 PM GMT, Ben Pfaff wrote: > Daniel Alvarez Sanchez reported a significant overall speedup in ovn-northd > due to a similar patch. > > Reported-by: Daniel Alvarez Sanchez <dalva...@redhat.com> > Reported-at: > https://mail.openvswitch.org/pipermail/ovs-discuss/2018-February/046120.html > Signed-off-by: Ben Pfaff <b...@ovn.org> > --- > lib/util.c | 39 +++++++++++++-------------------------- > 1 file changed, 13 insertions(+), 26 deletions(-) > > diff --git a/lib/util.c b/lib/util.c > index a4d22df0c359..2e7765e41f03 100644 > --- a/lib/util.c > +++ b/lib/util.c > @@ -843,32 +843,19 @@ str_to_double(const char *s, double *d) > int > hexit_value(int c) > { > - switch (c) { > - case '0': case '1': case '2': case '3': case '4': > - case '5': case '6': case '7': case '8': case '9': > - return c - '0'; > - > - case 'a': case 'A': > - return 0xa; > - > - case 'b': case 'B': > - return 0xb; > - > - case 'c': case 'C': > - return 0xc; > - > - case 'd': case 'D': > - return 0xd; > - > - case 'e': case 'E': > - return 0xe; > - > - case 'f': case 'F': > - return 0xf; > - > - default: > - return -1; > - } > + static const signed char tbl[UCHAR_MAX + 1] = { > +#define TBL(x) \ > + ( x >= '0' && x <= '9' ? x - '0' \ > + : x >= 'a' && x <= 'f' ? x - 'a' + 0xa \ > + : x >= 'A' && x <= 'F' ? x - 'A' + 0xa \ > + : -1) > +#define TBL0(x) TBL(x), TBL((x) + 1), TBL((x) + 2), TBL((x) + 3) > +#define TBL1(x) TBL0(x), TBL0((x) + 4), TBL0((x) + 8), TBL0((x) + 12) > +#define TBL2(x) TBL1(x), TBL1((x) + 16), TBL1((x) + 32), TBL1((x) + 48) > + TBL2(0), TBL2(64), TBL2(128), TBL2(192) > + }; > + > + return tbl[c]; > } > > /* Returns the integer value of the 'n' hexadecimal digits starting at 's', > or
It caught my attention that the contract with hexit_value() callers has changed. Previously we had a catch-all clause for out-of-range values. Now there will be an out-of-bounds read. Perhaps a check if input is in range would be in place? Or some kind of input sanitization like in the original patch? WDYT? -Jakub _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
