From: Joseph Myers Date: Wed, 26 Apr 2023 17:14:18 +0000 (+0000) Subject: Fix Hurd getcwd build with GCC >= 13 X-Git-Tag: upstream/2.39~875 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=af16a59ee1f72392b88d439d8f802c9844f86f4f;p=platform%2Fupstream%2Fglibc.git Fix Hurd getcwd build with GCC >= 13 The build of glibc for i686-gnu has been failing for a while with GCC mainline / GCC 13: ../sysdeps/mach/hurd/getcwd.c: In function '__hurd_canonicalize_directory_name_internal': ../sysdeps/mach/hurd/getcwd.c:242:48: error: pointer 'file_name' may be used after 'realloc' [-Werror=use-after-free] 242 | file_namep = &buf[file_namep - file_name + size / 2]; | ~~~~~~~~~~~^~~~~~~~~~~ ../sysdeps/mach/hurd/getcwd.c:236:25: note: call to 'realloc' here 236 | buf = realloc (file_name, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~ Fix by doing the subtraction before the reallocation. Tested with build-many-glibcs.py for i686-gnu. [samuel.thibault@ens-lyon.rg: Removed mention of this being a bug] Message-Id: <18587337-7815-4056-ebd0-724df262d591@codesourcery.com> --- diff --git a/sysdeps/mach/hurd/getcwd.c b/sysdeps/mach/hurd/getcwd.c index f24b35b380..cd3aedd9cd 100644 --- a/sysdeps/mach/hurd/getcwd.c +++ b/sysdeps/mach/hurd/getcwd.c @@ -222,8 +222,9 @@ __hurd_canonicalize_directory_name_internal (file_t thisdir, found: { /* Prepend the directory name just discovered. */ + size_t offset = file_namep - file_name; - if (file_namep - file_name < d->d_namlen + 1) + if (offset < d->d_namlen + 1) { if (orig_size > 0) { @@ -239,7 +240,7 @@ __hurd_canonicalize_directory_name_internal (file_t thisdir, free (file_name); return NULL; } - file_namep = &buf[file_namep - file_name + size / 2]; + file_namep = &buf[offset + size / 2]; file_name = buf; /* Move current contents up to the end of the buffer. This is guaranteed to be non-overlapping. */