R devel - Oct 2001 - psignrank and pwilcox null pointer deref (PR#1149)

Full_Name: Charles J. Geyer
Version: 1.3.1
OS: SuSE 7.2
Submission from: (NULL) (134.84.86.22)


in line 90 of signrank.c and lines 114 and 273 of wilcox.c calloc is used and
the return is not checked to see if it is null (violating numbers 2 and 6 of
the ten commandments for C programmers).  The following code thus makes
R segfault (for suitably large values of 1000)

for (n in seq(100, 1000, 100)) {
   mu <- n * (n + 1) / 4
   sigma <- sqrt(n * (n + 1) * (2 * n + 1) / 24)
   z <- floor(qnorm(0.05, mu, sigma))
   p <- psignrank(z, n)
   cat("z = ", z, ", n = ", n, ", p = ", p,
"\n", sep="")
}

for (n in seq(100, 1000, 100)) {
   m <- n
   mu <- n * m / 2
   sigma <- sqrt(m * n * (m + n + 1) / 12)
   z <- floor(qnorm(0.05, mu, sigma))
   p <- pwilcox(z, m, n)
   cat("z = ", z, ", m = ", m, ", n = ", n,
", p = ", p, "\n", sep="")
}

A fix is hard because a good solution would free all the previously allocated
memory before dying.  Probably a better algorithm is needed.  But I don't
know
if one exists.

Anyway the current behavior is unacceptable.







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