Commit f35f43f5 authored by Junio C Hamano's avatar Junio C Hamano

Merge branch 'jk/ewah-bounds-check'

The code to read compressed bitmap was not careful to avoid reading
past the end of the file, which has been corrected.

* jk/ewah-bounds-check:
  ewah: adjust callers of ewah_read_mmap()
  ewah_read_mmap: bounds-check mmap reads
parents 1663e2ba 1140bf01
......@@ -2853,7 +2853,8 @@ struct untracked_cache *read_untracked_extension(const void *data, unsigned long
struct read_data rd;
const unsigned char *next = data, *end = (const unsigned char *)data + sz;
const char *ident;
int ident_len, len;
int ident_len;
ssize_t len;
const char *exclude_per_dir;
if (sz <= 1 || end[-1] != '\0')
......
......@@ -122,16 +122,23 @@ int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
return ewah_serialize_to(self, write_strbuf, sb);
}
int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
{
const uint8_t *ptr = map;
size_t data_len;
size_t i;
if (len < sizeof(uint32_t))
return error("corrupt ewah bitmap: eof before bit size");
self->bit_size = get_be32(ptr);
ptr += sizeof(uint32_t);
len -= sizeof(uint32_t);
if (len < sizeof(uint32_t))
return error("corrupt ewah bitmap: eof before length");
self->buffer_size = self->alloc_size = get_be32(ptr);
ptr += sizeof(uint32_t);
len -= sizeof(uint32_t);
REALLOC_ARRAY(self->buffer, self->alloc_size);
......@@ -141,15 +148,25 @@ int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
* the endianness conversion in a separate pass to ensure
* we're loading 8-byte aligned words.
*/
memcpy(self->buffer, ptr, self->buffer_size * sizeof(eword_t));
ptr += self->buffer_size * sizeof(eword_t);
data_len = st_mult(self->buffer_size, sizeof(eword_t));
if (len < data_len)
return error("corrupt ewah bitmap: eof in data "
"(%"PRIuMAX" bytes short)",
(uintmax_t)(data_len - len));
memcpy(self->buffer, ptr, data_len);
ptr += data_len;
len -= data_len;
for (i = 0; i < self->buffer_size; ++i)
self->buffer[i] = ntohll(self->buffer[i]);
if (len < sizeof(uint32_t))
return error("corrupt ewah bitmap: eof before rlw");
self->rlw = self->buffer + get_be32(ptr);
ptr += sizeof(uint32_t);
len -= sizeof(uint32_t);
return (3 * 4) + (self->buffer_size * 8);
return ptr - (const uint8_t *)map;
}
int ewah_deserialize(struct ewah_bitmap *self, int fd)
......
......@@ -91,7 +91,7 @@ int ewah_serialize_native(struct ewah_bitmap *self, int fd);
int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *);
int ewah_deserialize(struct ewah_bitmap *self, int fd);
int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len);
ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len);
uint32_t ewah_checksum(struct ewah_bitmap *self);
......
......@@ -120,7 +120,7 @@ static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
{
struct ewah_bitmap *b = ewah_pool_new();
int bitmap_size = ewah_read_mmap(b,
ssize_t bitmap_size = ewah_read_mmap(b,
index->map + index->map_pos,
index->map_size - index->map_pos);
......
......@@ -331,4 +331,17 @@ test_expect_success 'pack reuse respects --incremental' '
git show-index <empty.idx >actual &&
test_cmp expect actual
'
test_expect_success 'truncated bitmap fails gracefully' '
git repack -ad &&
git rev-list --use-bitmap-index --count --all >expect &&
bitmap=$(ls .git/objects/pack/*.bitmap) &&
test_when_finished "rm -f $bitmap" &&
head -c 512 <$bitmap >$bitmap.tmp &&
mv -f $bitmap.tmp $bitmap &&
git rev-list --use-bitmap-index --count --all >actual 2>stderr &&
test_cmp expect actual &&
test_i18ngrep corrupt stderr
'
test_done
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