[git commit] mmap()->sys_mmap2: do unsigned shift of offset

[Mike Frysinger]

commit: http://git.uclibc.org/uClibc/commit/?id=a8908c3517cc93249bb6ec2c693cf80874c7f629
branch: http://git.uclibc.org/uClibc/commit/?id=refs/heads/master

Fix the implementation of mmap based on the mmap2 system call, to
construct pgoffset from offset with an unsigned shift rather than a
signed (off_t) shift. The mmap2 test in the testsuite catches this case
by mmap'ing with a large offset (with the sign bit set). The signed
shift repeats the sign bit making the page shift way out of range. This
is already fixed similarly in mmap64().

Signed-off-by: James Hogan <james.hogan at imgtec.com>
Signed-off-by: Mike Frysinger <vapier at gentoo.org>
---
 libc/sysdeps/linux/common/mmap.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/libc/sysdeps/linux/common/mmap.c b/libc/sysdeps/linux/common/mmap.c
index 8995898..d53eabb 100644
--- a/libc/sysdeps/linux/common/mmap.c
+++ b/libc/sysdeps/linux/common/mmap.c
@@ -63,7 +63,8 @@ __ptr_t mmap(__ptr_t addr, size_t len, int prot, int flags, int fd, __off_t offs
 		__set_errno(EINVAL);
 		return MAP_FAILED;
 	}
-	return __syscall_mmap2(addr, len, prot, flags, fd, offset >> MMAP2_PAGE_SHIFT);
+	return __syscall_mmap2(addr, len, prot, flags,
+	                       fd, ((__u_long) offset >> MMAP2_PAGE_SHIFT));
 }
 
 libc_hidden_def(mmap)