libarchive: import bugfix from upstream

Reworked bugfix for upstream issue #1566:
  Do not follow symlinks when processing the fixup list

MFC after:	2 weeks
This commit is contained in:
Martin Matuska 2021-08-27 12:51:01 +02:00
commit c577bdfce6
2 changed files with 78 additions and 28 deletions

View File

@ -2462,6 +2462,7 @@ _archive_write_disk_close(struct archive *_a)
struct archive_write_disk *a = (struct archive_write_disk *)_a;
struct fixup_entry *next, *p;
struct stat st;
char *c;
int fd, ret;
archive_check_magic(&a->archive, ARCHIVE_WRITE_DISK_MAGIC,
@ -2475,24 +2476,49 @@ _archive_write_disk_close(struct archive *_a)
while (p != NULL) {
fd = -1;
a->pst = NULL; /* Mark stat cache as out-of-date. */
if (p->fixup &
(TODO_TIMES | TODO_MODE_BASE | TODO_ACLS | TODO_FFLAGS)) {
fd = open(p->name,
O_WRONLY | O_BINARY | O_NOFOLLOW | O_CLOEXEC);
/* We must strip trailing slashes from the path to avoid
dereferencing symbolic links to directories */
c = p->name;
while (*c != '\0')
c++;
while (c != p->name && *(c - 1) == '/') {
c--;
*c = '\0';
}
if (p->fixup == 0)
goto skip_fixup_entry;
else {
fd = open(p->name, O_BINARY | O_NOFOLLOW | O_RDONLY
#if defined(O_DIRECTORY)
| O_DIRECTORY
#endif
| O_CLOEXEC);
/*
` * If we don't support O_DIRECTORY,
* or open() has failed, we must stat()
* to verify that we are opening a directory
*/
#if defined(O_DIRECTORY)
if (fd == -1) {
/* If we cannot lstat, skip entry */
if (lstat(p->name, &st) != 0)
if (lstat(p->name, &st) != 0 ||
!S_ISDIR(st.st_mode)) {
goto skip_fixup_entry;
/*
* If we deal with a symbolic link, mark
* it in the fixup mode to ensure no
* modifications are made to its target.
*/
if (S_ISLNK(st.st_mode)) {
p->mode &= ~S_IFMT;
p->mode |= S_IFLNK;
}
}
#else
#if HAVE_FSTAT
if (fd > 0 && (
fstat(fd, &st) != 0 || !S_ISDIR(st.st_mode))) {
goto skip_fixup_entry;
} else
#endif
if (lstat(p->name, &st) != 0 ||
!S_ISDIR(st.st_mode)) {
goto skip_fixup_entry;
}
#endif
}
if (p->fixup & TODO_TIMES) {
set_times(a, fd, p->mode, p->name,
@ -2504,14 +2530,13 @@ _archive_write_disk_close(struct archive *_a)
if (p->fixup & TODO_MODE_BASE) {
#ifdef HAVE_FCHMOD
if (fd >= 0)
fchmod(fd, p->mode);
fchmod(fd, p->mode & 07777);
else
#endif
#ifdef HAVE_LCHMOD
lchmod(p->name, p->mode);
lchmod(p->name, p->mode & 07777);
#else
if (!S_ISLNK(p->mode))
chmod(p->name, p->mode);
chmod(p->name, p->mode & 07777);
#endif
}
if (p->fixup & TODO_ACLS)
@ -2664,7 +2689,6 @@ new_fixup(struct archive_write_disk *a, const char *pathname)
fe->next = a->fixup_list;
a->fixup_list = fe;
fe->fixup = 0;
fe->mode = 0;
fe->name = strdup(pathname);
return (fe);
}

View File

@ -47,26 +47,50 @@ DEFINE_TEST(test_write_disk_fixup)
/*
* Create a file
*/
assertMakeFile("victim", 0600, "a");
assertMakeFile("file", 0600, "a");
/*
* Create a directory
*/
assertMakeDir("dir", 0700);
/*
* Create a directory and a symlink with the same name
*/
/* Directory: dir */
/* Directory: dir1 */
assert((ae = archive_entry_new()) != NULL);
archive_entry_copy_pathname(ae, "dir");
archive_entry_set_mode(ae, AE_IFDIR | 0606);
archive_entry_copy_pathname(ae, "dir1/");
archive_entry_set_mode(ae, AE_IFDIR | 0555);
assertEqualIntA(ad, 0, archive_write_header(ad, ae));
assertEqualIntA(ad, 0, archive_write_finish_entry(ad));
archive_entry_free(ae);
/* Symbolic Link: dir -> foo */
/* Directory: dir2 */
assert((ae = archive_entry_new()) != NULL);
archive_entry_copy_pathname(ae, "dir2/");
archive_entry_set_mode(ae, AE_IFDIR | 0555);
assertEqualIntA(ad, 0, archive_write_header(ad, ae));
assertEqualIntA(ad, 0, archive_write_finish_entry(ad));
archive_entry_free(ae);
/* Symbolic Link: dir1 -> dir */
assert((ae = archive_entry_new()) != NULL);
archive_entry_copy_pathname(ae, "dir");
archive_entry_copy_pathname(ae, "dir1");
archive_entry_set_mode(ae, AE_IFLNK | 0777);
archive_entry_set_size(ae, 0);
archive_entry_copy_symlink(ae, "victim");
archive_entry_copy_symlink(ae, "dir");
assertEqualIntA(ad, 0, r = archive_write_header(ad, ae));
if (r >= ARCHIVE_WARN)
assertEqualIntA(ad, 0, archive_write_finish_entry(ad));
archive_entry_free(ae);
/* Symbolic Link: dir2 -> file */
assert((ae = archive_entry_new()) != NULL);
archive_entry_copy_pathname(ae, "dir2");
archive_entry_set_mode(ae, AE_IFLNK | 0777);
archive_entry_set_size(ae, 0);
archive_entry_copy_symlink(ae, "file");
assertEqualIntA(ad, 0, r = archive_write_header(ad, ae));
if (r >= ARCHIVE_WARN)
assertEqualIntA(ad, 0, archive_write_finish_entry(ad));
@ -75,7 +99,9 @@ DEFINE_TEST(test_write_disk_fixup)
assertEqualInt(ARCHIVE_OK, archive_write_free(ad));
/* Test the entries on disk. */
assertIsSymlink("dir", "victim", 0);
assertFileMode("victim", 0600);
assertIsSymlink("dir1", "dir", 0);
assertIsSymlink("dir2", "file", 0);
assertFileMode("dir", 0700);
assertFileMode("file", 0600);
#endif
}