3 files changed, 27 insertions, 13 deletions

diff --git a/archival/libarchive/data_extract_all.c b/archival/libarchive/data_extract_all.c
index 049c2c156..8a69711c1 100644
--- a/archival/libarchive/data_extract_all.c
+++ b/archival/libarchive/data_extract_all.c
@@ -65,6 +65,14 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
                 } while (--n != 0);
         }
 #endif
+#if ENABLE_FEATURE_PATH_TRAVERSAL_PROTECTION
+        /* Strip leading "/" and up to last "/../" path component */
+        dst_name = (char *)strip_unsafe_prefix(dst_name);
+#endif
+// ^^^ This may be a problem if some applets do need to extract absolute names.
+// (Probably will need to invent ARCHIVE_ALLOW_UNSAFE_NAME flag).
+// You might think that rpm needs it, but in my tests rpm's internal cpio
+// archive has names like "./usr/bin/FOO", not "/usr/bin/FOO".
 
         if (archive_handle->ah_flags & ARCHIVE_CREATE_LEADING_DIRS) {
                 char *slash = strrchr(dst_name, '/');
diff --git a/archival/libarchive/open_transformer.c b/archival/libarchive/open_transformer.c
index 44715ef25..353f68217 100644
--- a/archival/libarchive/open_transformer.c
+++ b/archival/libarchive/open_transformer.c
@@ -157,7 +157,7 @@ void FAST_FUNC fork_transformer(int fd, const char *transform_prog)
 /* Used by e.g. rpm which gives us a fd without filename,
  * thus we can't guess the format from filename's extension.
  */
-static transformer_state_t *setup_transformer_on_fd(int fd, int fail_if_not_compressed)
+static transformer_state_t *setup_transformer_on_fd(int fd, int die_if_not_compressed)
 {
         transformer_state_t *xstate;
 
@@ -204,7 +204,7 @@ static transformer_state_t *setup_transformer_on_fd(int fd, int fail_if_not_comp
         }
 
         /* No known magic seen */
-        if (fail_if_not_compressed)
+        if (die_if_not_compressed)
                 bb_simple_error_msg_and_die("no gzip"
                         IF_FEATURE_SEAMLESS_BZ2("/bzip2")
                         IF_FEATURE_SEAMLESS_XZ("/xz")
@@ -240,13 +240,15 @@ static void fork_transformer_and_free(transformer_state_t *xstate)
 /* Used by e.g. rpm which gives us a fd without filename,
  * thus we can't guess the format from filename's extension.
  */
-int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_compressed)
+int FAST_FUNC setup_unzip_on_fd(int fd, int die_if_not_compressed)
 {
-        transformer_state_t *xstate = setup_transformer_on_fd(fd, fail_if_not_compressed);
+        transformer_state_t *xstate = setup_transformer_on_fd(fd, die_if_not_compressed);
 
         if (!xstate->xformer) {
+                /* Not compressed */
+                int retval = xstate->signature_skipped; /* never zero */
                 free(xstate);
-                return 1;
+                return retval;
         }
 
         fork_transformer_and_free(xstate);
@@ -264,7 +266,7 @@ void FAST_FUNC setup_lzma_on_fd(int fd)
 }
 #endif
 
-static transformer_state_t *open_transformer(const char *fname, int fail_if_not_compressed)
+static transformer_state_t *open_transformer(const char *fname, int die_if_not_compressed)
 {
         transformer_state_t *xstate;
         int fd;
@@ -284,18 +286,18 @@ static transformer_state_t *open_transformer(const char *fname, int fail_if_not_
                 }
         }
 
-        xstate = setup_transformer_on_fd(fd, fail_if_not_compressed);
+        xstate = setup_transformer_on_fd(fd, die_if_not_compressed);
 
         return xstate;
 }
 
-int FAST_FUNC open_zipped(const char *fname, int fail_if_not_compressed)
+int FAST_FUNC open_zipped(const char *fname, int die_if_not_compressed)
 {
         int fd;
         transformer_state_t *xstate;
 
-        xstate = open_transformer(fname, fail_if_not_compressed);
-        if (!xstate)
+        xstate = open_transformer(fname, die_if_not_compressed);
+        if (!xstate) /* open error */
                 return -1;
 
         fd = xstate->src_fd;
@@ -326,7 +328,7 @@ void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_
         transformer_state_t *xstate;
         char *image;
 
-        xstate = open_transformer(fname, /*fail_if_not_compressed:*/ 0);
+        xstate = open_transformer(fname, /*die_if_not_compressed:*/ 0);
         if (!xstate) /* file open error */
                 return NULL;
 
@@ -371,7 +373,7 @@ void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_
         int fd;
         char *image;
 
-        fd = open_zipped(fname, /*fail_if_not_compressed:*/ 0);
+        fd = open_zipped(fname, /*die_if_not_compressed:*/ 0);
         if (fd < 0)
                 return NULL;
 
diff --git a/archival/libarchive/unsafe_prefix.c b/archival/libarchive/unsafe_prefix.c
index 33e487bf9..667081195 100644
--- a/archival/libarchive/unsafe_prefix.c
+++ b/archival/libarchive/unsafe_prefix.c
@@ -14,7 +14,11 @@ const char* FAST_FUNC strip_unsafe_prefix(const char *str)
                         cp++;
                         continue;
                 }
-                if (is_prefixed_with(cp, "/../"+1)) {
+                /* We are called lots of times.
+                 * is_prefixed_with(cp, "../") is slower than open-coding it,
+                 * with minimal code growth (~few bytes).
+                 */
+                if (cp[0] == '.' && cp[1] == '.' && cp[2] == '/') {
                         cp += 3;
                         continue;
                 }