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Stop using alloca

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* gnulib.modules: Remove alloca.
* src/create.c (dump_file0): Return address of any allocated
storage.  Caller changed to free it.  Use xmalloc instead
of alloca, to obtain this storage.
* src/list.c (from_header): Use quote_mem instead of quote,
removing the need to use alloca.
This commit is contained in:
Paul Eggert
2023-08-02 08:41:12 -07:00
parent 9a30bb2674
commit 8e5483577d
4 changed files with 32 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
NEWS
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@@ -1,4 +1,4 @@
GNU tar NEWS - User visible changes. 2023-08-01
GNU tar NEWS - User visible changes. 2023-08-02
Please send GNU tar bug reports to <bug-tar@gnu.org>
version TBD
@@ -24,6 +24,10 @@ as argument to --mtime option (see GNU tar manual, chapter 4
Defines output format for the COMMAND set by the above option. If
used, command output will be parsed using strptime(3).
* Bug fixes
** tar no longer uses alloca, fixing an unlikely stack overflow.
version 1.35 - Sergey Poznyakoff, 2023-07-18

1
gnulib.modules
View File

@@ -18,7 +18,6 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
alloca
areadlinkat-with-size
argmatch
argp

51
src/create.c
View File

@@ -1638,12 +1638,15 @@ restore_parent_fd (struct tar_stat_info const *st)
/* Dump a single file, recursing on directories. ST is the file's
status info, NAME its name relative to the parent directory, and P
its full name (which may be relative to the working directory). */
its full name (which may be relative to the working directory).
Return the address of dynamically allocated storage that the caller
should free, or the null pointer if there is no such storage. */
/* FIXME: One should make sure that for *every* path leading to setting
exit_status to failure, a clear diagnostic has been issued. */
static void
static void *
dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
{
union block *header;
@@ -1657,7 +1660,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
void (*diag) (char const *) = 0;
if (interactive_option && !confirm ("add", p))
return;
return NULL;
assign_string (&st->orig_file_name, p);
assign_string (&st->file_name,
@@ -1687,7 +1690,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
if (diag)
{
file_removed_diag (p, top_level, diag);
return;
return NULL;
}
struct stat st1 = st->stat;
@@ -1696,16 +1699,13 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
st->mtime = get_stat_mtime (&st->stat);
st->ctime = get_stat_ctime (&st->stat);
void *allocated = NULL;
#ifdef S_ISHIDDEN
if (S_ISHIDDEN (st->stat.st_mode))
{
char *new = (char *) alloca (strlen (p) + 2);
if (new)
{
strcpy (new, p);
strcat (new, "@");
p = new;
}
allocated = xmalloc (strlen (p) + 2);
strcpy (stpcpy (allocated, p), "@");
p = allocated;
}
#endif
@@ -1724,7 +1724,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
WARNOPT (WARN_FILE_UNCHANGED,
(0, 0, _("%s: file is unchanged; not dumped"),
quotearg_colon (p)));
return;
return allocated;
}
/* See if we are trying to dump the archive. */
@@ -1733,13 +1733,13 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
WARNOPT (WARN_IGNORE_ARCHIVE,
(0, 0, _("%s: archive cannot contain itself; not dumped"),
quotearg_colon (p)));
return;
return allocated;
}
is_dir = S_ISDIR (st->stat.st_mode) != 0;
if (!is_dir && dump_hard_link (st))
return;
return allocated;
if (is_dir || S_ISREG (st->stat.st_mode) || S_ISCTG (st->stat.st_mode))
{
@@ -1760,7 +1760,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
{
exclusion_tag_warning (st->orig_file_name, tag_file_name,
_("directory not dumped"));
return;
return allocated;
}
ok = dump_dir (st);
@@ -1868,7 +1868,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
if (ok && remove_files_option)
queue_deferred_unlink (p, is_dir);
return;
return allocated;
}
#ifdef HAVE_READLINK
else if (S_ISLNK (st->stat.st_mode))
@@ -1879,7 +1879,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
if (errno == ENOMEM)
xalloc_die ();
file_removed_diag (p, top_level, readlink_diag);
return;
return allocated;
}
transform_name (&st->link_name, XFORM_SYMLINK);
if (NAME_FIELD_SIZE - (archive_format == OLDGNU_FORMAT)
@@ -1893,7 +1893,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
st->stat.st_size = 0; /* force 0 size on symlink */
header = start_header (st);
if (!header)
return;
return allocated;
tar_copy_str (header->header.linkname, st->link_name, NAME_FIELD_SIZE);
header->header.typeflag = SYMTYPE;
finish_header (st, header, block_ordinal);
@@ -1903,7 +1903,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
queue_deferred_unlink (p, false);
file_count_links (st);
return;
return allocated;
}
#endif
else if (S_ISCHR (st->stat.st_mode))
@@ -1931,35 +1931,36 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
{
WARNOPT (WARN_FILE_IGNORED,
(0, 0, _("%s: socket ignored"), quotearg_colon (p)));
return;
return allocated;
}
else if (S_ISDOOR (st->stat.st_mode))
{
WARNOPT (WARN_FILE_IGNORED,
(0, 0, _("%s: door ignored"), quotearg_colon (p)));
return;
return allocated;
}
else
{
unknown_file_error (p);
return;
return allocated;
}
if (archive_format == V7_FORMAT)
{
unknown_file_error (p);
return;
return allocated;
}
block_ordinal = current_block_ordinal ();
st->stat.st_size = 0; /* force 0 size */
header = start_header (st);
if (!header)
return;
return allocated;
header->header.typeflag = type;
finish_header (st, header, block_ordinal);
if (remove_files_option)
queue_deferred_unlink (p, false);
return allocated;
}
/* Dump a file, recursively. PARENT describes the file's parent
@@ -1974,7 +1975,7 @@ dump_file (struct tar_stat_info *parent, char const *name,
struct tar_stat_info st;
tar_stat_init (&st);
st.parent = parent;
dump_file0 (&st, name, fullname);
free (dump_file0 (&st, name, fullname));
if (parent && listed_incremental_option)
update_parent_directory (parent);
tar_stat_destroy (&st);

5
src/list.c
View File

@@ -868,13 +868,10 @@ from_header (char const *where0, size_t digs, char const *type,
{
if (value << LG_64 >> LG_64 != value)
{
char *string = alloca (digs + 1);
memcpy (string, where0, digs);
string[digs] = '\0';
if (type && !silent)
ERROR ((0, 0,
_("Archive signed base-64 string %s is out of %s range"),
quote (string), type));
quote_mem (where0, digs), type));
return -1;
}
value = (value << LG_64) | dig;