linear-assignment: fix potential out of bounds memory access

diff --git a/unpack-trees.c b/unpack-trees.c
index eb544ee1b3e789a5b2f3b1b73c30f3b99e84d774..f9efee0836a20e7072477ae0f3de7c9e1a29ff78 100644 (file)
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -16,6 +16,7 @@
 #include "submodule.h"
 #include "submodule-config.h"
 #include "fsmonitor.h"
+#include "object-store.h"
 #include "fetch-object.h"
 
 /*
@@ -203,20 +204,11 @@ static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
                               ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 }
 
-static struct cache_entry *dup_entry(const struct cache_entry *ce)
-{
-       unsigned int size = ce_size(ce);
-       struct cache_entry *new_entry = xmalloc(size);
-
-       memcpy(new_entry, ce, size);
-       return new_entry;
-}
-
 static void add_entry(struct unpack_trees_options *o,
                      const struct cache_entry *ce,
                      unsigned int set, unsigned int clear)
 {
-       do_add_entry(o, dup_entry(ce), set, clear);
+       do_add_entry(o, dup_cache_entry(ce, &o->result), set, clear);
 }
 
 /*
@@ -797,10 +789,17 @@ static int ce_in_traverse_path(const struct cache_entry *ce,
        return (info->pathlen < ce_namelen(ce));
 }
 
-static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
+static struct cache_entry *create_ce_entry(const struct traverse_info *info,
+       const struct name_entry *n,
+       int stage,
+       struct index_state *istate,
+       int is_transient)
 {
        int len = traverse_path_len(info, n);
-       struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
+       struct cache_entry *ce =
+               is_transient ?
+               make_empty_transient_cache_entry(len) :
+               make_empty_cache_entry(istate, len);
 
        ce->ce_mode = create_ce_mode(n->mode);
        ce->ce_flags = create_ce_flags(stage);
@@ -846,7 +845,15 @@ static int unpack_nondirectories(int n, unsigned long mask,
                        stage = 3;
                else
                        stage = 2;
-               src[i + o->merge] = create_ce_entry(info, names + i, stage);
+
+               /*
+                * If the merge bit is set, then the cache entries are
+                * discarded in the following block.  In this case,
+                * construct "transient" cache_entries, as they are
+                * not stored in the index.  otherwise construct the
+                * cache entry from the index aware logic.
+                */
+               src[i + o->merge] = create_ce_entry(info, names + i, stage, &o->result, o->merge);
        }
 
        if (o->merge) {
@@ -855,7 +862,7 @@ static int unpack_nondirectories(int n, unsigned long mask,
                for (i = 0; i < n; i++) {
                        struct cache_entry *ce = src[i + o->merge];
                        if (ce != o->df_conflict_entry)
-                               free(ce);
+                               discard_cache_entry(ce);
                }
                return rc;
        }
@@ -1787,7 +1794,7 @@ static int merged_entry(const struct cache_entry *ce,
                        struct unpack_trees_options *o)
 {
        int update = CE_UPDATE;
-       struct cache_entry *merge = dup_entry(ce);
+       struct cache_entry *merge = dup_cache_entry(ce, &o->result);
 
        if (!old) {
                /*
@@ -1807,7 +1814,7 @@ static int merged_entry(const struct cache_entry *ce,
 
                if (verify_absent(merge,
                                  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
-                       free(merge);
+                       discard_cache_entry(merge);
                        return -1;
                }
                invalidate_ce_path(merge, o);
@@ -1833,7 +1840,7 @@ static int merged_entry(const struct cache_entry *ce,
                        update = 0;
                } else {
                        if (verify_uptodate(old, o)) {
-                               free(merge);
+                               discard_cache_entry(merge);
                                return -1;
                        }
                        /* Migrate old flags over */