From 91ecbeca48e675fef8141451edb2c86577f9d63c Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Tue, 10 Apr 2007 00:15:41 -0400 Subject: [PATCH] validate reused pack data with CRC when possible This replaces the inflate validation with a CRC validation when reusing data from a pack which uses index version 2. That makes repacking much safer against corruptions, and it should be a bit faster too. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano --- builtin-pack-objects.c | 46 +++++++++++++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 12 deletions(-) diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index 099dea0e1..687b4b5a9 100644 --- a/builtin-pack-objects.c +++ b/builtin-pack-objects.c @@ -233,12 +233,6 @@ static struct revindex_entry * find_packed_object(struct packed_git *p, die("internal error: pack revindex corrupt"); } -static off_t find_packed_object_size(struct packed_git *p, off_t ofs) -{ - struct revindex_entry *entry = find_packed_object(p, ofs); - return entry[1].offset - ofs; -} - static const unsigned char *find_packed_object_name(struct packed_git *p, off_t ofs) { @@ -321,6 +315,28 @@ static int check_pack_inflate(struct packed_git *p, stream.total_in == len) ? 0 : -1; } +static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, + off_t offset, off_t len, unsigned int nr) +{ + const uint32_t *index_crc; + uint32_t data_crc = crc32(0, Z_NULL, 0); + + do { + unsigned int avail; + void *data = use_pack(p, w_curs, offset, &avail); + if (avail > len) + avail = len; + data_crc = crc32(data_crc, data, avail); + offset += avail; + len -= avail; + } while (len); + + index_crc = p->index_data; + index_crc += 2 + 256 + p->num_objects * (20/4) + nr; + + return data_crc != ntohl(*index_crc); +} + static void copy_pack_data(struct sha1file *f, struct packed_git *p, struct pack_window **w_curs, @@ -485,6 +501,7 @@ static unsigned long write_object(struct sha1file *f, else { struct packed_git *p = entry->in_pack; struct pack_window *w_curs = NULL; + struct revindex_entry *revidx; off_t offset; if (entry->delta) { @@ -507,12 +524,17 @@ static unsigned long write_object(struct sha1file *f, hdrlen += 20; } - offset = entry->in_pack_offset + entry->in_pack_header_size; - datalen = find_packed_object_size(p, entry->in_pack_offset) - - entry->in_pack_header_size; - if (!pack_to_stdout && check_pack_inflate(p, &w_curs, - offset, datalen, entry->size)) - die("corrupt delta in pack %s", sha1_to_hex(entry->sha1)); + offset = entry->in_pack_offset; + revidx = find_packed_object(p, offset); + datalen = revidx[1].offset - offset; + if (!pack_to_stdout && p->index_version > 1 && + check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) + die("bad packed object CRC for %s", sha1_to_hex(entry->sha1)); + offset += entry->in_pack_header_size; + datalen -= entry->in_pack_header_size; + if (!pack_to_stdout && p->index_version == 1 && + check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) + die("corrupt packed object for %s", sha1_to_hex(entry->sha1)); copy_pack_data(f, p, &w_curs, offset, datalen); unuse_pack(&w_curs); reused++; -- 2.30.2