340 lines
12 KiB
Diff
340 lines
12 KiB
Diff
From 5abe86f88de3c61e369483a55afe771cce646135 Mon Sep 17 00:00:00 2001
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From: Pavel Raiskup <praiskup@redhat.com>
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Date: Tue, 26 Jan 2016 23:17:54 +0100
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Subject: [PATCH 3/4] CVE-2016-2037 - 1 byte out-of-bounds write
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Ensure that cpio_safer_name_suffix always works with dynamically
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allocated buffer, and that it has size of at least 32 bytes.
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Then, any call to cpio_safer_name_suffix is safe (it requires at
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least 2 bytes in the buffer).
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Also ensure that c_namesize is always correctly initialized (by
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cpio_set_c_name) to avoid undefined behavior when reading
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file_hdr.c_namesize (previously happened for tar archives).
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References:
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http://www.mail-archive.com/bug-cpio@gnu.org/msg00545.html
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* src/copyin.c (query_rename): Drop the hack, as we now work with
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dynamically allocated buffer. Use cpio_set_c_name.
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(create_defered_links_to_skipped): Use cpio_set_c_name rather than
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manual assignment.
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(read_name_from_file): New function to avoid C&P.
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(read_in_old_ascii, read_in_new_ascii, read_in_binary): Use
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read_name_from_file.
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(process_copy_in): Initialize file_hdr.c_namesize.
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* src/copyout.c (process_copy_out): Use cpio_set_c_name.
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* src/cpiohdr.h (cpio_set_c_name): New prototype.
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* src/tar.c (read_in_tar_header): Use cpio_set_c_name.
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* src/util.c (cpio_set_c_name): New function to set
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file_hdr->c_name and c_namesize from arbitrary string.
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(cpio_safer_name_suffix): Some docs fixes.
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* tests/inout.at: Also test copy-in, and try various formats.
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---
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src/copyin.c | 68 ++++++++++++++++----------------------------------
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src/copyout.c | 13 ++++------
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src/cpiohdr.h | 1 +
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src/tar.c | 10 +++++---
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src/util.c | 32 +++++++++++++++++++++++-
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tests/inout.at | 19 ++++++++++++--
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6 files changed, 82 insertions(+), 61 deletions(-)
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diff --git src/copyin.c src/copyin.c
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index 05279d2..06ee1c3 100644
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--- src/copyin.c
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+++ src/copyin.c
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@@ -76,28 +76,7 @@ query_rename(struct cpio_file_stat* file_hdr, FILE *tty_in, FILE *tty_out,
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return -1;
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}
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else
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- /* Debian hack: file_hrd.c_name is sometimes set to
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- point to static memory by code in tar.c. This
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- causes a segfault. This has been fixed and an
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- additional check to ensure that the file name
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- is not too long has been added. (Reported by
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- Horst Knobloch.) This bug has been reported to
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- "bug-gnu-utils@prep.ai.mit.edu". (99/1/6) -BEM */
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- {
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- if (archive_format != arf_tar && archive_format != arf_ustar)
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- {
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- free (file_hdr->c_name);
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- file_hdr->c_name = xstrdup (new_name.ds_string);
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- }
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- else
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- {
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- if (is_tar_filename_too_long (new_name.ds_string))
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- error (0, 0, _("%s: file name too long"),
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- new_name.ds_string);
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- else
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- strcpy (file_hdr->c_name, new_name.ds_string);
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- }
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- }
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+ cpio_set_c_name (file_hdr, new_name.ds_string);
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return 0;
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}
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@@ -344,8 +323,7 @@ create_defered_links_to_skipped (struct cpio_file_stat *file_hdr,
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d_prev->next = d->next;
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else
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deferments = d->next;
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- free (file_hdr->c_name);
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- file_hdr->c_name = xstrdup(d->header.c_name);
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+ cpio_set_c_name (file_hdr, d->header.c_name);
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free_deferment (d);
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copyin_regular_file(file_hdr, in_file_des);
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return 0;
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@@ -1064,6 +1042,22 @@ read_in_header (struct cpio_file_stat *file_hdr, int in_des)
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}
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}
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+static void
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+read_name_from_file (struct cpio_file_stat *file_hdr, int fd, uintmax_t len)
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+{
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+ static char *tmp_filename;
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+ static size_t buflen;
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+
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+ if (buflen < len)
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+ {
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+ buflen = len;
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+ tmp_filename = xrealloc (tmp_filename, buflen);
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+ }
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+
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+ tape_buffered_read (tmp_filename, fd, len);
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+ cpio_set_c_name (file_hdr, tmp_filename);
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+}
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+
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/* Fill in FILE_HDR by reading an old-format ASCII format cpio header from
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file descriptor IN_DES, except for the magic number, which is
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already filled in. */
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@@ -1090,14 +1084,8 @@ read_in_old_ascii (struct cpio_file_stat *file_hdr, int in_des)
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file_hdr->c_rdev_min = minor (dev);
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file_hdr->c_mtime = FROM_OCTAL (ascii_header.c_mtime);
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- file_hdr->c_namesize = FROM_OCTAL (ascii_header.c_namesize);
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file_hdr->c_filesize = FROM_OCTAL (ascii_header.c_filesize);
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-
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- /* Read file name from input. */
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- if (file_hdr->c_name != NULL)
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- free (file_hdr->c_name);
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- file_hdr->c_name = (char *) xmalloc (file_hdr->c_namesize + 1);
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- tape_buffered_read (file_hdr->c_name, in_des, (long) file_hdr->c_namesize);
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+ read_name_from_file (file_hdr, in_des, FROM_OCTAL (ascii_header.c_namesize));
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/* HP/UX cpio creates archives that look just like ordinary archives,
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but for devices it sets major = 0, minor = 1, and puts the
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@@ -1152,14 +1140,8 @@ read_in_new_ascii (struct cpio_file_stat *file_hdr, int in_des)
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file_hdr->c_dev_min = FROM_HEX (ascii_header.c_dev_min);
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file_hdr->c_rdev_maj = FROM_HEX (ascii_header.c_rdev_maj);
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file_hdr->c_rdev_min = FROM_HEX (ascii_header.c_rdev_min);
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- file_hdr->c_namesize = FROM_HEX (ascii_header.c_namesize);
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file_hdr->c_chksum = FROM_HEX (ascii_header.c_chksum);
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-
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- /* Read file name from input. */
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- if (file_hdr->c_name != NULL)
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- free (file_hdr->c_name);
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- file_hdr->c_name = (char *) xmalloc (file_hdr->c_namesize);
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- tape_buffered_read (file_hdr->c_name, in_des, (long) file_hdr->c_namesize);
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+ read_name_from_file (file_hdr, in_des, FROM_HEX (ascii_header.c_namesize));
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/* In SVR4 ASCII format, the amount of space allocated for the header
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is rounded up to the next long-word, so we might need to drop
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@@ -1207,16 +1189,9 @@ read_in_binary (struct cpio_file_stat *file_hdr,
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file_hdr->c_rdev_min = minor (short_hdr->c_rdev);
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file_hdr->c_mtime = (unsigned long) short_hdr->c_mtimes[0] << 16
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| short_hdr->c_mtimes[1];
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-
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- file_hdr->c_namesize = short_hdr->c_namesize;
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file_hdr->c_filesize = (unsigned long) short_hdr->c_filesizes[0] << 16
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| short_hdr->c_filesizes[1];
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-
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- /* Read file name from input. */
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- if (file_hdr->c_name != NULL)
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- free (file_hdr->c_name);
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- file_hdr->c_name = (char *) xmalloc (file_hdr->c_namesize);
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- tape_buffered_read (file_hdr->c_name, in_des, (long) file_hdr->c_namesize);
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+ read_name_from_file (file_hdr, in_des, short_hdr->c_namesize);
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/* In binary mode, the amount of space allocated in the header for
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the filename is `c_namesize' rounded up to the next short-word,
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@@ -1297,6 +1272,7 @@ process_copy_in ()
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read_pattern_file ();
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}
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file_hdr.c_name = NULL;
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+ file_hdr.c_namesize = 0;
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if (rename_batch_file)
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{
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diff --git src/copyout.c src/copyout.c
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index 1f0987a..bb39559 100644
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--- src/copyout.c
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+++ src/copyout.c
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@@ -660,8 +660,7 @@ process_copy_out ()
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cpio_safer_name_suffix (input_name.ds_string, false,
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!no_abs_paths_flag, true);
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#ifndef HPUX_CDF
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- file_hdr.c_name = input_name.ds_string;
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- file_hdr.c_namesize = strlen (input_name.ds_string) + 1;
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+ cpio_set_c_name (&file_hdr, input_name.ds_string);
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#else
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if ( (archive_format != arf_tar) && (archive_format != arf_ustar) )
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{
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@@ -670,16 +669,15 @@ process_copy_out ()
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properly recreate the directory as hidden (in case the
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files of a directory go into the archive before the
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directory itself (e.g from "find ... -depth ... | cpio")). */
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- file_hdr.c_name = add_cdf_double_slashes (input_name.ds_string);
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- file_hdr.c_namesize = strlen (file_hdr.c_name) + 1;
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+ cpio_set_c_name (&file_hdr,
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+ add_cdf_double_slashes (input_name.ds_string));
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}
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else
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{
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/* We don't mark CDF's in tar files. We assume the "hidden"
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directory will always go into the archive before any of
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its files. */
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- file_hdr.c_name = input_name.ds_string;
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- file_hdr.c_namesize = strlen (input_name.ds_string) + 1;
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+ cpio_set_c_name (&file_hdr, input_name.ds_string);
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}
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#endif
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@@ -866,8 +864,7 @@ process_copy_out ()
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file_hdr.c_chksum = 0;
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file_hdr.c_filesize = 0;
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- file_hdr.c_namesize = 11;
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- file_hdr.c_name = CPIO_TRAILER_NAME;
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+ cpio_set_c_name (&file_hdr, CPIO_TRAILER_NAME);
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if (archive_format != arf_tar && archive_format != arf_ustar)
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write_out_header (&file_hdr, out_file_des);
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else
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diff --git src/cpiohdr.h src/cpiohdr.h
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index b29e6fb..f4c63be 100644
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--- src/cpiohdr.h
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+++ src/cpiohdr.h
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@@ -129,5 +129,6 @@ struct cpio_file_stat /* Internal representation of a CPIO header */
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char *c_tar_linkname;
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};
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+void cpio_set_c_name(struct cpio_file_stat *file_hdr, char *name);
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#endif /* cpiohdr.h */
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diff --git src/tar.c src/tar.c
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index a2ce171..e41f89d 100644
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--- src/tar.c
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+++ src/tar.c
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@@ -282,7 +282,7 @@ read_in_tar_header (struct cpio_file_stat *file_hdr, int in_des)
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if (null_block ((long *) &tar_rec, TARRECORDSIZE))
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#endif
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{
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- file_hdr->c_name = CPIO_TRAILER_NAME;
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+ cpio_set_c_name (file_hdr, CPIO_TRAILER_NAME);
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return;
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}
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#if 0
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@@ -316,9 +316,11 @@ read_in_tar_header (struct cpio_file_stat *file_hdr, int in_des)
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}
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if (archive_format != arf_ustar)
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- file_hdr->c_name = stash_tar_filename (NULL, tar_hdr->name);
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+ cpio_set_c_name (file_hdr, stash_tar_filename (NULL, tar_hdr->name));
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else
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- file_hdr->c_name = stash_tar_filename (tar_hdr->prefix, tar_hdr->name);
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+ cpio_set_c_name (file_hdr, stash_tar_filename (tar_hdr->prefix,
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+ tar_hdr->name));
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+
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file_hdr->c_nlink = 1;
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file_hdr->c_mode = FROM_OCTAL (tar_hdr->mode);
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file_hdr->c_mode = file_hdr->c_mode & 07777;
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@@ -398,7 +400,7 @@ read_in_tar_header (struct cpio_file_stat *file_hdr, int in_des)
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case AREGTYPE:
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/* Old tar format; if the last char in filename is '/' then it is
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a directory, otherwise it's a regular file. */
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- if (file_hdr->c_name[strlen (file_hdr->c_name) - 1] == '/')
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+ if (file_hdr->c_name[file_hdr->c_namesize - 1] == '/')
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file_hdr->c_mode |= CP_IFDIR;
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else
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file_hdr->c_mode |= CP_IFREG;
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diff --git src/util.c src/util.c
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index 6ff6032..4f3c073 100644
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--- src/util.c
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+++ src/util.c
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@@ -1410,8 +1410,34 @@ set_file_times (int fd,
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utime_error (name);
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}
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+
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+void
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+cpio_set_c_name (struct cpio_file_stat *file_hdr, char *name)
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+{
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+ static size_t buflen = 0;
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+ size_t len = strlen (name) + 1;
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+
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+ if (buflen == 0)
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+ {
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+ buflen = len;
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+ if (buflen < 32)
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+ buflen = 32;
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+ file_hdr->c_name = xmalloc (buflen);
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+ }
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+ else if (buflen < len)
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+ {
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+ buflen = len;
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+ file_hdr->c_name = xrealloc (file_hdr->c_name, buflen);
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+ }
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+
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+ file_hdr->c_namesize = len;
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+ memmove (file_hdr->c_name, name, len);
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+}
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+
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/* Do we have to ignore absolute paths, and if so, does the filename
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- have an absolute path? */
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+ have an absolute path? Before calling this function make sure that the
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+ allocated NAME buffer has capacity at least 2 bytes. */
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+
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void
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cpio_safer_name_suffix (char *name, bool link_target, bool absolute_names,
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bool strip_leading_dots)
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@@ -1426,6 +1452,10 @@ cpio_safer_name_suffix (char *name, bool link_target, bool absolute_names,
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++p;
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}
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if (p != name)
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+ /* The 'p' string is shortened version of 'name' with one exception; when
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+ the 'name' points to an empty string (buffer where name[0] == '\0') the
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+ 'p' then points to static string ".". So caller needs to ensure there
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+ are at least two bytes available in 'name' buffer so memmove succeeds. */
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memmove (name, p, (size_t)(strlen (p) + 1));
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}
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diff --git tests/inout.at tests/inout.at
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index 60c3716..730cbd2 100644
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--- tests/inout.at
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+++ tests/inout.at
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@@ -35,7 +35,22 @@ while read NAME LENGTH
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do
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genfile --length $LENGTH > $NAME
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echo $NAME
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-done < filelist |
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- cpio --quiet -o > archive])
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+done < filelist > filelist_raw
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+
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+for format in bin odc newc crc tar ustar hpbin hpodc
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+do
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+ cpio --format=$format --quiet -o < filelist_raw > archive.$format
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+ rm -rf output
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+ mkdir output && cd output
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+ cpio -i --quiet < ../archive.$format
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+
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+ while read file
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+ do
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+ test -f $file || echo "$file not found"
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+ done < ../filelist_raw
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+
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+ cd ..
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+done
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+])
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AT_CLEANUP
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--
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2.20.1
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