Revision e1d911dd4c7b76a5a8cec0f5c8de15981e34da83 authored by Johannes Schindelin on 12 September 2019, 12:54:05 UTC, committed by Johannes Schindelin on 04 December 2019, 12:20:05 UTC
The backslash character is not a valid part of a file name on Windows. Hence it is dangerous to allow writing files that were unpacked from tree objects, when the stored file name contains a backslash character: it will be misinterpreted as directory separator. This not only causes ambiguity when a tree contains a blob `a\b` and a tree `a` that contains a blob `b`, but it also can be used as part of an attack vector to side-step the careful protections against writing into the `.git/` directory during a clone of a maliciously-crafted repository. Let's prevent that, addressing CVE-2019-1354. Note: we guard against backslash characters in tree objects' file names _only_ on Windows (because on other platforms, even on those where NTFS volumes can be mounted, the backslash character is _not_ a directory separator), and _only_ when `core.protectNTFS = true` (because users might need to generate tree objects for other platforms, of course without touching the worktree, e.g. using `git update-index --cacheinfo`). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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oidset.c
#include "cache.h"
#include "oidset.h"
struct oidset_entry {
struct hashmap_entry hash;
struct object_id oid;
};
static int oidset_hashcmp(const void *unused_cmp_data,
const void *va, const void *vb,
const void *vkey)
{
const struct oidset_entry *a = va, *b = vb;
const struct object_id *key = vkey;
return oidcmp(&a->oid, key ? key : &b->oid);
}
int oidset_contains(const struct oidset *set, const struct object_id *oid)
{
struct hashmap_entry key;
if (!set->map.cmpfn)
return 0;
hashmap_entry_init(&key, sha1hash(oid->hash));
return !!hashmap_get(&set->map, &key, oid);
}
int oidset_insert(struct oidset *set, const struct object_id *oid)
{
struct oidset_entry *entry;
if (!set->map.cmpfn)
hashmap_init(&set->map, oidset_hashcmp, NULL, 0);
if (oidset_contains(set, oid))
return 1;
entry = xmalloc(sizeof(*entry));
hashmap_entry_init(&entry->hash, sha1hash(oid->hash));
oidcpy(&entry->oid, oid);
hashmap_add(&set->map, entry);
return 0;
}
void oidset_clear(struct oidset *set)
{
hashmap_free(&set->map, 1);
}
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