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![Junio C Hamano](/assets/img/avatar_default.png)
Running the SHA1_Update() on the whole packfile in a single call
revealed an overflow problem we had in the SHA-1 implementation
on POWER architecture some time ago, which was fixed with commit
b47f509b
(June 19, 2006). Other SHA-1 implementations may have
a similar problem.
The sliding mmap() series already makes chunked calls to
SHA1_Update(), so this patch itself will become moot when it
graduates to "master", but in the meantime, run the hash
function in smaller chunks to prevent possible future problems.
Signed-off-by: Junio C Hamano <junkio@cox.net>
159 lines
4.1 KiB
C
159 lines
4.1 KiB
C
#include "cache.h"
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#include "pack.h"
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static int verify_packfile(struct packed_git *p,
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struct pack_window **w_curs)
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{
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unsigned long index_size = p->index_size;
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void *index_base = p->index_base;
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SHA_CTX ctx;
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unsigned char sha1[20];
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unsigned long offset = 0, pack_sig = p->pack_size - 20;
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int nr_objects, err, i;
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/* Note that the pack header checks are actually performed by
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* use_pack when it first opens the pack file. If anything
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* goes wrong during those checks then the call will die out
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* immediately.
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*/
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SHA1_Init(&ctx);
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while (offset < pack_sig) {
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unsigned int remaining;
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unsigned char *in = use_pack(p, w_curs, offset, &remaining);
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offset += remaining;
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if (offset > pack_sig)
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remaining -= offset - pack_sig;
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SHA1_Update(&ctx, in, remaining);
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}
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SHA1_Final(sha1, &ctx);
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if (hashcmp(sha1, use_pack(p, w_curs, pack_sig, NULL)))
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return error("Packfile %s SHA1 mismatch with itself",
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p->pack_name);
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if (hashcmp(sha1, (unsigned char *)index_base + index_size - 40))
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return error("Packfile %s SHA1 mismatch with idx",
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p->pack_name);
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unuse_pack(w_curs);
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/* Make sure everything reachable from idx is valid. Since we
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* have verified that nr_objects matches between idx and pack,
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* we do not do scan-streaming check on the pack file.
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*/
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nr_objects = num_packed_objects(p);
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for (i = err = 0; i < nr_objects; i++) {
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unsigned char sha1[20];
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void *data;
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char type[20];
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unsigned long size, offset;
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if (nth_packed_object_sha1(p, i, sha1))
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die("internal error pack-check nth-packed-object");
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offset = find_pack_entry_one(sha1, p);
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if (!offset)
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die("internal error pack-check find-pack-entry-one");
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data = unpack_entry(p, offset, type, &size);
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if (!data) {
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err = error("cannot unpack %s from %s",
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sha1_to_hex(sha1), p->pack_name);
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continue;
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}
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if (check_sha1_signature(sha1, data, size, type)) {
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err = error("packed %s from %s is corrupt",
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sha1_to_hex(sha1), p->pack_name);
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free(data);
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continue;
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}
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free(data);
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}
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return err;
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}
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#define MAX_CHAIN 40
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static void show_pack_info(struct packed_git *p)
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{
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int nr_objects, i;
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unsigned int chain_histogram[MAX_CHAIN];
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nr_objects = num_packed_objects(p);
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memset(chain_histogram, 0, sizeof(chain_histogram));
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for (i = 0; i < nr_objects; i++) {
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unsigned char sha1[20], base_sha1[20];
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char type[20];
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unsigned long size;
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unsigned long store_size;
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unsigned long offset;
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unsigned int delta_chain_length;
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if (nth_packed_object_sha1(p, i, sha1))
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die("internal error pack-check nth-packed-object");
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offset = find_pack_entry_one(sha1, p);
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if (!offset)
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die("internal error pack-check find-pack-entry-one");
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packed_object_info_detail(p, offset, type, &size, &store_size,
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&delta_chain_length,
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base_sha1);
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printf("%s ", sha1_to_hex(sha1));
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if (!delta_chain_length)
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printf("%-6s %lu %lu\n", type, size, offset);
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else {
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printf("%-6s %lu %lu %u %s\n", type, size, offset,
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delta_chain_length, sha1_to_hex(base_sha1));
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if (delta_chain_length < MAX_CHAIN)
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chain_histogram[delta_chain_length]++;
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else
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chain_histogram[0]++;
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}
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}
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for (i = 0; i < MAX_CHAIN; i++) {
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if (!chain_histogram[i])
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continue;
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printf("chain length %s %d: %d object%s\n",
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i ? "=" : ">=",
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i ? i : MAX_CHAIN,
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chain_histogram[i],
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1 < chain_histogram[i] ? "s" : "");
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}
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}
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int verify_pack(struct packed_git *p, int verbose)
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{
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unsigned long index_size = p->index_size;
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void *index_base = p->index_base;
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SHA_CTX ctx;
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unsigned char sha1[20];
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int ret;
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ret = 0;
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/* Verify SHA1 sum of the index file */
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SHA1_Init(&ctx);
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SHA1_Update(&ctx, index_base, index_size - 20);
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SHA1_Final(sha1, &ctx);
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if (hashcmp(sha1, (unsigned char *)index_base + index_size - 20))
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ret = error("Packfile index for %s SHA1 mismatch",
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p->pack_name);
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if (!ret) {
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/* Verify pack file */
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struct pack_window *w_curs = NULL;
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ret = verify_packfile(p, &w_curs);
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unuse_pack(&w_curs);
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}
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if (verbose) {
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if (ret)
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printf("%s: bad\n", p->pack_name);
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else {
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show_pack_info(p);
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printf("%s: ok\n", p->pack_name);
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}
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}
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return ret;
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}
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