[PATCH v1 1/3] String: Add additional overflow tests for strnlen, memchr, and strncat

Noah Goldstein goldstein.w.n@gmail.com
Wed Jun 9 22:26:05 GMT 2021


On Wed, Jun 9, 2021 at 5:54 PM H.J. Lu <hjl.tools@gmail.com> wrote:

> On Wed, Jun 9, 2021 at 1:53 PM Noah Goldstein <goldstein.w.n@gmail.com>
> wrote:
> >
> > This commit adds tests for a bug in the wide char variant of the
> > functions where the implementation may assume that maxlen for wcsnlen
> > or n for wmemchr/strncat will not overflow when multiplied by
> > sizeof(wchar_t).
> >
> > These tests show the following implementations failing on x86_64:
> >
> > wcsnlen-sse4_1
> > wcsnlen-avx2
> >
> > wmemchr-sse2
> > wmemchr-avx2
> >
> > strncat would fail as well if it where on a system that prefered
> > either of the wcsnlen implementations that failed as it relies on
> > wcsnlen.
>
> Please open a bug report for each standard C function.   We need to
> track them for backporting to release branches.
>

Done: https://sourceware.org/bugzilla/show_bug.cgi?id=27974


>
> Thanks.
>
> > Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
> > ---
> >  string/test-memchr.c  | 39 ++++++++++++++++++++++++---
> >  string/test-strncat.c | 61 +++++++++++++++++++++++++++++++++++++++++++
> >  string/test-strnlen.c | 33 +++++++++++++++++++++++
> >  3 files changed, 130 insertions(+), 3 deletions(-)
> >
> > diff --git a/string/test-memchr.c b/string/test-memchr.c
> > index 665edc32af..ce964284aa 100644
> > --- a/string/test-memchr.c
> > +++ b/string/test-memchr.c
> > @@ -65,8 +65,8 @@ do_one_test (impl_t *impl, const CHAR *s, int c,
> size_t n, CHAR *exp_res)
> >    CHAR *res = CALL (impl, s, c, n);
> >    if (res != exp_res)
> >      {
> > -      error (0, 0, "Wrong result in function %s %p %p", impl->name,
> > -            res, exp_res);
> > +      error (0, 0, "Wrong result in function %s (%p, %d, %zu) -> %p !=
> %p",
> > +             impl->name, s, c, n, res, exp_res);
> >        ret = 1;
> >        return;
> >      }
> > @@ -91,7 +91,7 @@ do_test (size_t align, size_t pos, size_t len, size_t
> n, int seek_char)
> >      }
> >    buf[align + len] = 0;
> >
> > -  if (pos < len)
> > +  if (pos < MIN(n, len))
> >      {
> >        buf[align + pos] = seek_char;
> >        buf[align + len] = -seek_char;
> > @@ -107,6 +107,38 @@ do_test (size_t align, size_t pos, size_t len,
> size_t n, int seek_char)
> >      do_one_test (impl, (CHAR *) (buf + align), seek_char, n, result);
> >  }
> >
> > +static void
> > +do_overflow_tests (void)
> > +{
> > +  size_t i, j, len;
> > +  const size_t one = 1;
> > +  uintptr_t buf_addr = (uintptr_t) buf1;
> > +
> > +  for (i = 0; i < 750; ++i)
> > +    {
> > +        do_test (0, i, 751, SIZE_MAX - i, BIG_CHAR);
> > +        do_test (0, i, 751, i - buf_addr, BIG_CHAR);
> > +        do_test (0, i, 751, -buf_addr - i, BIG_CHAR);
> > +        do_test (0, i, 751, SIZE_MAX - buf_addr - i, BIG_CHAR);
> > +        do_test (0, i, 751, SIZE_MAX - buf_addr + i, BIG_CHAR);
> > +
> > +      len = 0;
> > +      for (j = 8 * sizeof(size_t) - 1; j ; --j)
> > +        {
> > +          len |= one << j;
> > +          do_test (0, i, 751, len - i, BIG_CHAR);
> > +          do_test (0, i, 751, len + i, BIG_CHAR);
> > +          do_test (0, i, 751, len - buf_addr - i, BIG_CHAR);
> > +          do_test (0, i, 751, len - buf_addr + i, BIG_CHAR);
> > +
> > +          do_test (0, i, 751, ~len - i, BIG_CHAR);
> > +          do_test (0, i, 751, ~len + i, BIG_CHAR);
> > +          do_test (0, i, 751, ~len - buf_addr - i, BIG_CHAR);
> > +          do_test (0, i, 751, ~len - buf_addr + i, BIG_CHAR);
> > +        }
> > +    }
> > +}
> > +
> >  static void
> >  do_random_tests (void)
> >  {
> > @@ -221,6 +253,7 @@ test_main (void)
> >      do_test (page_size / 2 - i, i, i, 1, 0x9B);
> >
> >    do_random_tests ();
> > +  do_overflow_tests ();
> >    return ret;
> >  }
> >
> > diff --git a/string/test-strncat.c b/string/test-strncat.c
> > index 2ef917b820..0ab7541d4e 100644
> > --- a/string/test-strncat.c
> > +++ b/string/test-strncat.c
> > @@ -134,6 +134,66 @@ do_test (size_t align1, size_t align2, size_t len1,
> size_t len2,
> >      }
> >  }
> >
> > +static void
> > +do_overflow_tests (void)
> > +{
> > +  size_t i, j, len;
> > +  const size_t one = 1;
> > +  CHAR *s1, *s2;
> > +  uintptr_t s1_addr;
> > +  s1 = (CHAR *) buf1;
> > +  s2 = (CHAR *) buf2;
> > +  s1_addr = (uintptr_t)s1;
> > + for (j = 0; j < 200; ++j)
> > +      s2[j] = 32 + 23 * j % (BIG_CHAR - 32);
> > + s2[200] = 0;
> > +  for (i = 0; i < 750; ++i) {
> > +    for (j = 0; j < i; ++j)
> > +      s1[j] = 32 + 23 * j % (BIG_CHAR - 32);
> > +    s1[i] = '\0';
> > +
> > +       FOR_EACH_IMPL (impl, 0)
> > +    {
> > +      s2[0] = '\0';
> > +      do_one_test (impl, s2, s1, SIZE_MAX - i);
> > +      s2[0] = '\0';
> > +      do_one_test (impl, s2, s1, i - s1_addr);
> > +      s2[0] = '\0';
> > +      do_one_test (impl, s2, s1, -s1_addr - i);
> > +      s2[0] = '\0';
> > +      do_one_test (impl, s2, s1, SIZE_MAX - s1_addr - i);
> > +      s2[0] = '\0';
> > +      do_one_test (impl, s2, s1, SIZE_MAX - s1_addr + i);
> > +    }
> > +
> > +    len = 0;
> > +    for (j = 8 * sizeof(size_t) - 1; j ; --j)
> > +      {
> > +        len |= one << j;
> > +        FOR_EACH_IMPL (impl, 0)
> > +          {
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, len - i);
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, len + i);
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, len - s1_addr - i);
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, len - s1_addr + i);
> > +
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, ~len - i);
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, ~len + i);
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, ~len - s1_addr - i);
> > +            s2[0] = '\0';
> > +            do_one_test (impl, s2, s1, ~len - s1_addr + i);
> > +          }
> > +      }
> > +  }
> > +}
> > +
> >  static void
> >  do_random_tests (void)
> >  {
> > @@ -316,6 +376,7 @@ test_main (void)
> >      }
> >
> >    do_random_tests ();
> > +  do_overflow_tests ();
> >    return ret;
> >  }
> >
> > diff --git a/string/test-strnlen.c b/string/test-strnlen.c
> > index 920f58e97b..f53e09263f 100644
> > --- a/string/test-strnlen.c
> > +++ b/string/test-strnlen.c
> > @@ -89,6 +89,38 @@ do_test (size_t align, size_t len, size_t maxlen, int
> max_char)
> >      do_one_test (impl, (CHAR *) (buf + align), maxlen, MIN (len,
> maxlen));
> >  }
> >
> > +static void
> > +do_overflow_tests (void)
> > +{
> > +  size_t i, j, len;
> > +  const size_t one = 1;
> > +  uintptr_t buf_addr = (uintptr_t) buf1;
> > +
> > +  for (i = 0; i < 750; ++i)
> > +    {
> > +      do_test (0, i, SIZE_MAX - i, BIG_CHAR);
> > +      do_test (0, i, i - buf_addr, BIG_CHAR);
> > +      do_test (0, i, -buf_addr - i, BIG_CHAR);
> > +      do_test (0, i, SIZE_MAX - buf_addr - i, BIG_CHAR);
> > +      do_test (0, i, SIZE_MAX - buf_addr + i, BIG_CHAR);
> > +
> > +      len = 0;
> > +      for (j = 8 * sizeof(size_t) - 1; j ; --j)
> > +        {
> > +          len |= one << j;
> > +          do_test (0, i, len - i, BIG_CHAR);
> > +          do_test (0, i, len + i, BIG_CHAR);
> > +          do_test (0, i, len - buf_addr - i, BIG_CHAR);
> > +          do_test (0, i, len - buf_addr + i, BIG_CHAR);
> > +
> > +          do_test (0, i, ~len - i, BIG_CHAR);
> > +          do_test (0, i, ~len + i, BIG_CHAR);
> > +          do_test (0, i, ~len - buf_addr - i, BIG_CHAR);
> > +          do_test (0, i, ~len - buf_addr + i, BIG_CHAR);
> > +        }
> > +    }
> > +}
> > +
> >  static void
> >  do_random_tests (void)
> >  {
> > @@ -283,6 +315,7 @@ test_main (void)
> >    do_random_tests ();
> >    do_page_tests ();
> >    do_page_2_tests ();
> > +  do_overflow_tests ();
> >    return ret;
> >  }
> >
> > --
> > 2.25.1
> >
>
>
> --
> H.J.
>


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