CBL-Mariner/SPECS-EXTENDED/zziplib/CVE-2018-17828.part2.patch

56 lines
1.8 KiB
Diff

diff --git a/bins/unzip-mem.c b/bins/unzip-mem.c
index c45cb72..ff564a5 100644
--- a/bins/unzip-mem.c
+++ b/bins/unzip-mem.c
@@ -88,10 +88,49 @@ static void zzip_mem_entry_pipe(ZZIP_MEM_DISK* disk,
}
}
+static inline void
+remove_dotdotslash(char *path)
+{
+ /* Note: removing "../" from the path ALWAYS shortens the path, never adds to it! */
+ char *dotdotslash;
+ int warned = 0;
+
+ dotdotslash = path;
+ while ((dotdotslash = strstr(dotdotslash, "../")) != NULL)
+ {
+ /*
+ * Remove only if at the beginning of the pathname ("../path/name")
+ * or when preceded by a slash ("path/../name"),
+ * otherwise not ("path../name..")!
+ */
+ if (dotdotslash == path || dotdotslash[-1] == '/')
+ {
+ char *src, *dst;
+ if (!warned)
+ {
+ /* Note: the first time through the pathname is still intact */
+ fprintf(stderr, "Removing \"../\" path component(s) in %s\n", path);
+ warned = 1;
+ }
+ /* We cannot use strcpy(), as there "The strings may not overlap" */
+ for (src = dotdotslash+3, dst=dotdotslash; (*dst = *src) != '\0'; src++, dst++)
+ ;
+ }
+ else
+ dotdotslash +=3; /* skip this instance to prevent infinite loop */
+ }
+}
+
static void zzip_mem_entry_make(ZZIP_MEM_DISK* disk,
ZZIP_MEM_ENTRY* entry)
{
- FILE* file = fopen (entry->zz_name, "wb");
+ char name_stripped[PATH_MAX];
+ FILE* file;
+
+ strncpy(name_stripped, entry->zz_name, PATH_MAX);
+ remove_dotdotslash(name_stripped);
+
+ file = fopen (name_stripped, "wb");
if (file) { zzip_mem_entry_pipe (disk, entry, file); fclose (file); }
perror (entry->zz_name);
if (status < EXIT_WARNINGS) status = EXIT_WARNINGS;