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| author | Denys Vlasenko | 2017-08-10 11:52:42 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2017-08-10 11:52:42 +0200 |
| commit | bc9bbeb2b81001e8731cd2ae501c8fccc8d87cc7 (patch) | |
| tree | 72672bb0c187b93f1fba99012cf0c4e716214298 /archival/libarchive/data_extract_all.c | |
| parent | 0cf64c8b5d86d603903397bfce87dea5a862caec (diff) | |
| download | busybox-bc9bbeb2b81001e8731cd2ae501c8fccc8d87cc7.zip busybox-bc9bbeb2b81001e8731cd2ae501c8fccc8d87cc7.tar.gz | |
libarchive: do not extract unsafe symlinks unless $EXTRACT_UNSAFE_SYMLINKS=1
function old new delta
unsafe_symlink_target - 147 +147
unzip_main 2711 2732 +21
copy_file 1657 1678 +21
tar_main 999 971 -28
data_extract_all 1038 984 -54
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 2/2 up/down: 189/-82) Total: 107 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival/libarchive/data_extract_all.c')
| -rw-r--r-- | archival/libarchive/data_extract_all.c | 37 |
1 files changed, 15 insertions, 22 deletions
diff --git a/archival/libarchive/data_extract_all.c b/archival/libarchive/data_extract_all.c index 1ce927c..e658444 100644 --- a/archival/libarchive/data_extract_all.c +++ b/archival/libarchive/data_extract_all.c @@ -129,9 +129,7 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle) if (res != 0 && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)) { /* shared message */ bb_perror_msg("can't create %slink '%s' to '%s'", - "hard", - dst_name, - hard_link + "hard", dst_name, hard_link ); } /* Hardlinks have no separate mode/ownership, skip chown/chmod */ @@ -181,7 +179,9 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle) //TODO: what if file_header->link_target == NULL (say, corrupted tarball?) /* To avoid a directory traversal attack via symlinks, - * for certain link targets postpone creation of symlinks. + * do not restore symlinks with ".." components + * or symlinks starting with "/", unless a magic + * envvar is set. * * For example, consider a .tar created via: * $ tar cvf bug.tar anything.txt @@ -199,24 +199,17 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle) * * Untarring bug.tar would otherwise place evil.py in '/tmp'. */ - if (file_header->link_target[0] == '/' - || strstr(file_header->link_target, "..") - ) { - llist_add_to(&archive_handle->symlink_placeholders, - xasprintf("%s%c%s", file_header->name, '\0', file_header->link_target) - ); - break; - } - res = symlink(file_header->link_target, dst_name); - if (res != 0 - && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET) - ) { - /* shared message */ - bb_perror_msg("can't create %slink '%s' to '%s'", - "sym", - dst_name, - file_header->link_target - ); + if (!unsafe_symlink_target(file_header->link_target)) { + res = symlink(file_header->link_target, dst_name); + if (res != 0 + && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET) + ) { + /* shared message */ + bb_perror_msg("can't create %slink '%s' to '%s'", + "sym", + dst_name, file_header->link_target + ); + } } break; case S_IFSOCK: |