kconfig: loop boundary condition fix
If buf[-1] just happens to hold the byte 0x0A, then nread can wrap around
to (size_t)-1, leading to invalid memory accesses.
This has caused segmentation faults when trying to build the latest
kernel snapshots for i686 in Fedora:
https://bugzilla.redhat.com/show_bug.cgi?id=1592374
Signed-off-by: Jerry James <loganjerry@gmail.com>
[alexpl@fedoraproject.org: reformatted patch for submission]
Signed-off-by: Alexander Ploumistos <alexpl@fedoraproject.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/kconfig/preprocess.c b/scripts/kconfig/preprocess.c
index 65da87f..5ca2df7 100644
--- a/scripts/kconfig/preprocess.c
+++ b/scripts/kconfig/preprocess.c
@@ -156,7 +156,7 @@ static char *do_shell(int argc, char *argv[])
nread--;
/* remove trailing new lines */
- while (buf[nread - 1] == '\n')
+ while (nread > 0 && buf[nread - 1] == '\n')
nread--;
buf[nread] = 0;
