undef/git-commit-vandalism
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Merge branch 'jh/verify-index-checksum-only-in-fsck'

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The index file has a trailing SHA-1 checksum to detect file
corruption, and historically we checked it every time the index
file is used.  Omit the validation during normal use, and instead
verify only in "git fsck".

* jh/verify-index-checksum-only-in-fsck:
  read-cache: force_verify_index_checksum
This commit is contained in:
Junio C Hamano 2017-04-23 22:07:49 -07:00
commit cdfe138b36
4 changed files with 23 additions and 0 deletions
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1
builtin/fsck.c
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@ -771,6 +771,7 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
} }
if (keep_cache_objects) { if (keep_cache_objects) {
verify_index_checksum = 1;
read_cache(); read_cache();
for (i = 0; i < active_nr; i++) { for (i = 0; i < active_nr; i++) {
unsigned int mode; unsigned int mode;

2
cache.h
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@ -710,6 +710,8 @@ extern void update_index_if_able(struct index_state *, struct lock_file *);
extern int hold_locked_index(struct lock_file *, int); extern int hold_locked_index(struct lock_file *, int);
extern void set_alternate_index_output(const char *); extern void set_alternate_index_output(const char *);
extern int verify_index_checksum;
/* Environment bits from configuration mechanism */ /* Environment bits from configuration mechanism */
extern int trust_executable_bit; extern int trust_executable_bit;
extern int trust_ctime; extern int trust_ctime;

7
read-cache.c
View File

@ -1371,6 +1371,9 @@ struct ondisk_cache_entry_extended {
ondisk_cache_entry_extended_size(ce_namelen(ce)) : \ ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
ondisk_cache_entry_size(ce_namelen(ce))) ondisk_cache_entry_size(ce_namelen(ce)))
/* Allow fsck to force verification of the index checksum. */
int verify_index_checksum;
static int verify_hdr(struct cache_header *hdr, unsigned long size) static int verify_hdr(struct cache_header *hdr, unsigned long size)
{ {
git_SHA_CTX c; git_SHA_CTX c;
@ -1382,6 +1385,10 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size)
hdr_version = ntohl(hdr->hdr_version); hdr_version = ntohl(hdr->hdr_version);
if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version) if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
return error("bad index version %d", hdr_version); return error("bad index version %d", hdr_version);
if (!verify_index_checksum)
return 0;
git_SHA1_Init(&c); git_SHA1_Init(&c);
git_SHA1_Update(&c, hdr, size - 20); git_SHA1_Update(&c, hdr, size - 20);
git_SHA1_Final(sha1, &c); git_SHA1_Final(sha1, &c);

13
t/t1450-fsck.sh
View File

@ -689,4 +689,17 @@ test_expect_success 'bogus head does not fallback to all heads' '
! grep $blob out ! grep $blob out
' '
test_expect_success 'detect corrupt index file in fsck' '
cp .git/index .git/index.backup &&
test_when_finished "mv .git/index.backup .git/index" &&
echo zzzzzzzz >zzzzzzzz &&
git add zzzzzzzz &&
sed -e "s/zzzzzzzz/yyyyyyyy/" .git/index >.git/index.yyy &&
mv .git/index.yyy .git/index &&
# Confirm that fsck detects invalid checksum
test_must_fail git fsck --cache &&
# Confirm that status no longer complains about invalid checksum
git status
'
test_done test_done