From 4fa8ae49aa169fb8d97882938e8bee3ed9ce5410 Mon Sep 17 00:00:00 2001 From: DJ Delorie Date: Fri, 14 Jul 2017 21:46:42 -0400 Subject: [PATCH] Fix BZ #21654 - grp-merge.c alignment * grp/grp_merge.c (__copy_grp): Align char** to minimum pointer alignment not char alignment. (__merge_grp): Likewise. --- ChangeLog | 7 +++++++ grp/grp-merge.c | 16 ++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/grp/grp-merge.c b/grp/grp-merge.c index 77c494d..6590e5d 100644 --- a/grp/grp-merge.c +++ b/grp/grp-merge.c @@ -85,6 +85,14 @@ __copy_grp (const struct group srcgrp, const size_t buflen, } members[i] = NULL; + /* Align for pointers. We can't simply align C because we need to + align destbuf[c]. */ + if ((((uintptr_t)destbuf + c) & (__alignof__(char **) - 1)) != 0) + { + uintptr_t mis_align = ((uintptr_t)destbuf + c) & (__alignof__(char **) - 1); + c += __alignof__(char **) - mis_align; + } + /* Copy the pointers from the members array into the buffer and assign them to the gr_mem member of destgrp. */ destgrp->gr_mem = (char **) &destbuf[c]; @@ -168,6 +176,14 @@ __merge_grp (struct group *savedgrp, char *savedbuf, char *savedend, /* Add the NULL-terminator. */ members[savedmemcount + memcount] = NULL; + /* Align for pointers. We can't simply align C because we need to + align savedbuf[c]. */ + if ((((uintptr_t)savedbuf + c) & (__alignof__(char **) - 1)) != 0) + { + uintptr_t mis_align = ((uintptr_t)savedbuf + c) & (__alignof__(char **) - 1); + c += __alignof__(char **) - mis_align; + } + /* Copy the member array back into the buffer after the member list and free the member array. */ savedgrp->gr_mem = (char **) &savedbuf[c]; -- 1.8.3.1