aboutsummaryrefslogtreecommitdiff
path: root/archival/libarchive/unsafe_symlink_target.c
diff options
context:
space:
mode:
authorGravatar Denys Vlasenko <vda.linux@googlemail.com>2018-02-20 15:57:45 +0100
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2018-03-10 19:41:54 +0100
commit37277a23fe48b13313f5d96084d890ed21d5fd8b (patch)
treee8a7964ad8fb1ba25aee2c54d434c2239b93faa2 /archival/libarchive/unsafe_symlink_target.c
parente3821088af5fb663be756c3330b52d1b48ad699e (diff)
downloadbusybox-37277a23fe48b13313f5d96084d890ed21d5fd8b.tar.gz
busybox-37277a23fe48b13313f5d96084d890ed21d5fd8b.tar.bz2
tar,unzip: postpone creation of symlinks with "suspicious" targets
This mostly reverts commit bc9bbeb2b81001e8731cd2ae501c8fccc8d87cc7 "libarchive: do not extract unsafe symlinks unless $EXTRACT_UNSAFE_SYMLINKS=1" Users report that it is somewhat too restrictive. See https://bugs.busybox.net/show_bug.cgi?id=8411 In particular, this interferes with unpacking of busybox-based filesystems with links like "sbin/applet" -> "../bin/busybox". The change is made smaller by deleting ARCHIVE_EXTRACT_QUIET flag - it is unused since 2010, and removing conditionals on it allows commonalizing some error message codes. function old new delta create_or_remember_symlink - 94 +94 create_symlinks_from_list - 64 +64 tar_main 1002 1006 +4 unzip_main 2732 2724 -8 data_extract_all 984 891 -93 unsafe_symlink_target 147 - -147 ------------------------------------------------------------------------------ (add/remove: 2/1 grow/shrink: 1/2 up/down: 162/-248) Total: -86 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival/libarchive/unsafe_symlink_target.c')
-rw-r--r--archival/libarchive/unsafe_symlink_target.c59
1 files changed, 26 insertions, 33 deletions
diff --git a/archival/libarchive/unsafe_symlink_target.c b/archival/libarchive/unsafe_symlink_target.c
index 441ba8b24..8dcafeaa1 100644
--- a/archival/libarchive/unsafe_symlink_target.c
+++ b/archival/libarchive/unsafe_symlink_target.c
@@ -5,44 +5,37 @@
#include "libbb.h"
#include "bb_archive.h"
-int FAST_FUNC unsafe_symlink_target(const char *target)
+void FAST_FUNC create_or_remember_symlink(llist_t **symlink_placeholders,
+ const char *target,
+ const char *linkname)
{
- const char *dot;
-
- if (target[0] == '/') {
- const char *var;
- unsafe:
- var = getenv("EXTRACT_UNSAFE_SYMLINKS");
- if (var) {
- if (LONE_CHAR(var, '1'))
- return 0; /* pretend it's safe */
- return 1; /* "UNSAFE!" */
- }
- bb_error_msg("skipping unsafe symlink to '%s' in archive,"
- " set %s=1 to extract",
- target,
- "EXTRACT_UNSAFE_SYMLINKS"
+ if (target[0] == '/' || strstr(target, "..")) {
+ llist_add_to(symlink_placeholders,
+ xasprintf("%s%c%s", linkname, '\0', target)
+ );
+ return;
+ }
+ if (symlink(target, linkname) != 0) {
+ /* shared message */
+ bb_perror_msg_and_die("can't create %slink '%s' to '%s'",
+ "sym", linkname, target
);
- /* Prevent further messages */
- setenv("EXTRACT_UNSAFE_SYMLINKS", "0", 0);
- return 1; /* "UNSAFE!" */
}
+}
- dot = target;
- for (;;) {
- dot = strchr(dot, '.');
- if (!dot)
- return 0; /* safe target */
+void FAST_FUNC create_symlinks_from_list(llist_t *list)
+{
+ while (list) {
+ char *target;
- /* Is it a path component starting with ".."? */
- if ((dot[1] == '.')
- && (dot == target || dot[-1] == '/')
- /* Is it exactly ".."? */
- && (dot[2] == '/' || dot[2] == '\0')
- ) {
- goto unsafe;
+ target = list->data + strlen(list->data) + 1;
+ if (symlink(target, list->data)) {
+ /* shared message */
+ bb_error_msg_and_die("can't create %slink '%s' to '%s'",
+ "sym",
+ list->data, target
+ );
}
- /* NB: it can even be trailing ".", should only add 1 */
- dot += 1;
+ list = list->link;
}
}