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authorDJ Delorie <dj@delorie.com>2017-07-14 21:46:42 -0400
committerDJ Delorie <dj@delorie.com>2017-07-14 21:46:42 -0400
commit4fa8ae49aa169fb8d97882938e8bee3ed9ce5410 (patch)
tree61b1f4b60f4c03f089c210a33714138516ddb57b /grp
parentde895ddcd7fc45caeeeb0ae312311b8bd31d82c5 (diff)
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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.
Diffstat (limited to 'grp')
-rw-r--r--grp/grp-merge.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/grp/grp-merge.c b/grp/grp-merge.c
index 77c494d159..6590e5d823 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];