| From 59357157706d47c365b2227739e17daba3607526 Mon Sep 17 00:00:00 2001 |
| From: Alessandro Ghedini <alessandro@ghedini.me> |
| Date: Sun, 1 Mar 2015 12:07:45 +0100 |
| Subject: [PATCH] Add ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS option |
| |
| This fixes a directory traversal in the cpio tool. |
| |
| |
| Upstream-Status: backport |
| |
| Signed-off-by: Li Zhou <li.zhou@windriver.com> |
| --- |
| cpio/bsdcpio.1 | 3 ++- |
| cpio/cpio.c | 2 ++ |
| libarchive/archive.h | 2 ++ |
| libarchive/archive_write_disk.3 | 3 +++ |
| libarchive/archive_write_disk_posix.c | 14 +++++++++++--- |
| libarchive/test/test_write_disk_secure.c | 23 +++++++++++++++++++++++ |
| 6 files changed, 43 insertions(+), 4 deletions(-) |
| |
| diff --git a/cpio/bsdcpio.1 b/cpio/bsdcpio.1 |
| index f966aa0..e52546e 100644 |
| --- a/cpio/bsdcpio.1 |
| +++ b/cpio/bsdcpio.1 |
| @@ -156,7 +156,8 @@ See above for description. |
| .It Fl Fl insecure |
| (i and p mode only) |
| Disable security checks during extraction or copying. |
| -This allows extraction via symbolic links and path names containing |
| +This allows extraction via symbolic links, absolute paths, |
| +and path names containing |
| .Sq .. |
| in the name. |
| .It Fl J , Fl Fl xz |
| diff --git a/cpio/cpio.c b/cpio/cpio.c |
| index 0acde11..b267e9b 100644 |
| --- a/cpio/cpio.c |
| +++ b/cpio/cpio.c |
| @@ -171,6 +171,7 @@ main(int argc, char *argv[]) |
| cpio->extract_flags |= ARCHIVE_EXTRACT_NO_OVERWRITE_NEWER; |
| cpio->extract_flags |= ARCHIVE_EXTRACT_SECURE_SYMLINKS; |
| cpio->extract_flags |= ARCHIVE_EXTRACT_SECURE_NODOTDOT; |
| + cpio->extract_flags |= ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS; |
| cpio->extract_flags |= ARCHIVE_EXTRACT_PERM; |
| cpio->extract_flags |= ARCHIVE_EXTRACT_FFLAGS; |
| cpio->extract_flags |= ARCHIVE_EXTRACT_ACL; |
| @@ -256,6 +257,7 @@ main(int argc, char *argv[]) |
| case OPTION_INSECURE: |
| cpio->extract_flags &= ~ARCHIVE_EXTRACT_SECURE_SYMLINKS; |
| cpio->extract_flags &= ~ARCHIVE_EXTRACT_SECURE_NODOTDOT; |
| + cpio->extract_flags &= ~ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS; |
| break; |
| case 'L': /* GNU cpio */ |
| cpio->option_follow_links = 1; |
| diff --git a/libarchive/archive.h b/libarchive/archive.h |
| index 1f0fc38..ef635ac 100644 |
| --- a/libarchive/archive.h |
| +++ b/libarchive/archive.h |
| @@ -649,6 +649,8 @@ __LA_DECL int archive_read_set_passphrase_callback(struct archive *, |
| /* Default: Do not use HFS+ compression if it was not compressed. */ |
| /* This has no effect except on Mac OS v10.6 or later. */ |
| #define ARCHIVE_EXTRACT_HFS_COMPRESSION_FORCED (0x8000) |
| +/* Default: Do not reject entries with absolute paths */ |
| +#define ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS (0x10000) |
| |
| __LA_DECL int archive_read_extract(struct archive *, struct archive_entry *, |
| int flags); |
| diff --git a/libarchive/archive_write_disk.3 b/libarchive/archive_write_disk.3 |
| index fa925cc..a2e7afa 100644 |
| --- a/libarchive/archive_write_disk.3 |
| +++ b/libarchive/archive_write_disk.3 |
| @@ -177,6 +177,9 @@ The default is to not refuse such paths. |
| Note that paths ending in |
| .Pa .. |
| always cause an error, regardless of this flag. |
| +.It Cm ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS |
| +Refuse to extract an absolute path. |
| +The default is to not refuse such paths. |
| .It Cm ARCHIVE_EXTRACT_SPARSE |
| Scan data for blocks of NUL bytes and try to recreate them with holes. |
| This results in sparse files, independent of whether the archive format |
| diff --git a/libarchive/archive_write_disk_posix.c b/libarchive/archive_write_disk_posix.c |
| index ab3bdac..c1290eb 100644 |
| --- a/libarchive/archive_write_disk_posix.c |
| +++ b/libarchive/archive_write_disk_posix.c |
| @@ -2509,8 +2509,9 @@ cleanup_pathname_win(struct archive_write_disk *a) |
| /* |
| * Canonicalize the pathname. In particular, this strips duplicate |
| * '/' characters, '.' elements, and trailing '/'. It also raises an |
| - * error for an empty path, a trailing '..' or (if _SECURE_NODOTDOT is |
| - * set) any '..' in the path. |
| + * error for an empty path, a trailing '..', (if _SECURE_NODOTDOT is |
| + * set) any '..' in the path or (if ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS |
| + * is set) if the path is absolute. |
| */ |
| static int |
| cleanup_pathname(struct archive_write_disk *a) |
| @@ -2529,8 +2530,15 @@ cleanup_pathname(struct archive_write_disk *a) |
| cleanup_pathname_win(a); |
| #endif |
| /* Skip leading '/'. */ |
| - if (*src == '/') |
| + if (*src == '/') { |
| + if (a->flags & ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS) { |
| + archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, |
| + "Path is absolute"); |
| + return (ARCHIVE_FAILED); |
| + } |
| + |
| separator = *src++; |
| + } |
| |
| /* Scan the pathname one element at a time. */ |
| for (;;) { |
| diff --git a/libarchive/test/test_write_disk_secure.c b/libarchive/test/test_write_disk_secure.c |
| index 31c5bfd..2c94206 100644 |
| --- a/libarchive/test/test_write_disk_secure.c |
| +++ b/libarchive/test/test_write_disk_secure.c |
| @@ -178,6 +178,29 @@ DEFINE_TEST(test_write_disk_secure) |
| assert(S_ISDIR(st.st_mode)); |
| archive_entry_free(ae); |
| |
| + /* |
| + * Without security checks, we should be able to |
| + * extract an absolute path. |
| + */ |
| + assert((ae = archive_entry_new()) != NULL); |
| + archive_entry_copy_pathname(ae, "/tmp/libarchive_test-test_write_disk_secure-absolute_path.tmp"); |
| + archive_entry_set_mode(ae, S_IFREG | 0777); |
| + assert(0 == archive_write_header(a, ae)); |
| + assert(0 == archive_write_finish_entry(a)); |
| + assertFileExists("/tmp/libarchive_test-test_write_disk_secure-absolute_path.tmp"); |
| + assert(0 == unlink("/tmp/libarchive_test-test_write_disk_secure-absolute_path.tmp")); |
| + |
| + /* But with security checks enabled, this should fail. */ |
| + assert(archive_entry_clear(ae) != NULL); |
| + archive_entry_copy_pathname(ae, "/tmp/libarchive_test-test_write_disk_secure-absolute_path.tmp"); |
| + archive_entry_set_mode(ae, S_IFREG | 0777); |
| + archive_write_disk_set_options(a, ARCHIVE_EXTRACT_SECURE_NOABSOLUTEPATHS); |
| + failure("Extracting an absolute path should fail here."); |
| + assertEqualInt(ARCHIVE_FAILED, archive_write_header(a, ae)); |
| + archive_entry_free(ae); |
| + assert(0 == archive_write_finish_entry(a)); |
| + assertFileNotExists("/tmp/libarchive_test-test_write_disk_secure-absolute_path.tmp"); |
| + |
| assertEqualInt(ARCHIVE_OK, archive_write_free(a)); |
| |
| /* Test the entries on disk. */ |
| -- |
| 1.7.9.5 |
| |