fcntl receiving -1 from fileno, fcntl failing.

(Also very few spots of negative numgroups for getgroups(),
and fgetc() return, but almost all checking is for fcntl.)

(merged fix for perl #121743 and perl #121745: hopefully
picked up all the fixes-to-fixes from the ticket...)

Fix for Coverity perl5 CIDs 28990..29003,29005..29011,29013,
45354,45363,49926:

Argument cannot be negative (NEGATIVE_RETURNS) fd is
passed to a parameter that cannot be negative.

and CIDs 29004, 29012:
Argument cannot be negative (NEGATIVE_RETURNS)
num_groups is passed to a parameter that cannot be negative

and because of CIDs 29005 and 29006 also CID 28924.

In the first set of issues a fd is retrieved from PerlIO_fileno, and
that is then used in places like fstat(), fchown(), dup(), etc.,
without checking whether the fd is valid (>=0).

In the second set of issues a potentially negative
number is potentially passed to getgroups().

The CIDs 29005 and 29006 were a bit messy: fixing them needed also
resolving CID 28924 where the return value of fstat() was ignored,
and for completeness adding two croak calls (with perldiag updates):
a bit of a waste since it's suidperl code.

1 files changed, 5 insertions, 1 deletions

diff --git a/ext/PerlIO-mmap/mmap.xs b/ext/PerlIO-mmap/mmap.xs
index 4c96da84f7..6632544c76 100644
--- a/ext/PerlIO-mmap/mmap.xs
+++ b/ext/PerlIO-mmap/mmap.xs
@@ -40,8 +40,12 @@ PerlIOMmap_map(pTHX_ PerlIO *f)
 	abort();
     if (flags & PERLIO_F_CANREAD) {
 	PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
-	const int fd = PerlIO_fileno(f);
 	Stat_t st;
+	const int fd = PerlIO_fileno(f);
+        if (fd < 0) {
+          SETERRNO(EBADF,RMS_IFI);
+          return -1;
+        }
 	code = Fstat(fd, &st);
 	if (code == 0 && S_ISREG(st.st_mode)) {
 	    SSize_t len = st.st_size - b->posn;