From c479d14a80743b1cb86d77695607f4c81f7d8797 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Sat, 28 Jul 2012 11:06:29 -0400 Subject: [PATCH] fsck: detect null sha1 in tree entries Short of somebody happening to beat the 1 in 2^160 odds of actually generating content that hashes to the null sha1, we should never see this value in a tree entry. So let's have fsck warn if it it seen. As in the previous commit, we test both blob and submodule entries to future-proof the test suite against the implementation depending on connectivity to notice the error. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- fsck.c | 8 +++++++- t/t1450-fsck.sh | 26 ++++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/fsck.c b/fsck.c index 6c855f84f..da53cf41f 100644 --- a/fsck.c +++ b/fsck.c @@ -139,6 +139,7 @@ static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, con static int fsck_tree(struct tree *item, int strict, fsck_error error_func) { int retval; + int has_null_sha1 = 0; int has_full_path = 0; int has_empty_name = 0; int has_zero_pad = 0; @@ -157,9 +158,12 @@ static int fsck_tree(struct tree *item, int strict, fsck_error error_func) while (desc.size) { unsigned mode; const char *name; + const unsigned char *sha1; - tree_entry_extract(&desc, &name, &mode); + sha1 = tree_entry_extract(&desc, &name, &mode); + if (is_null_sha1(sha1)) + has_null_sha1 = 1; if (strchr(name, '/')) has_full_path = 1; if (!*name) @@ -207,6 +211,8 @@ static int fsck_tree(struct tree *item, int strict, fsck_error error_func) } retval = 0; + if (has_null_sha1) + retval += error_func(&item->object, FSCK_WARN, "contains entries pointing to null sha1"); if (has_full_path) retval += error_func(&item->object, FSCK_WARN, "contains full pathnames"); if (has_empty_name) diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh index 5b8ebd805..5e36cc71b 100755 --- a/t/t1450-fsck.sh +++ b/t/t1450-fsck.sh @@ -217,4 +217,30 @@ test_expect_success 'rev-list --verify-objects with bad sha1' ' grep -q "error: sha1 mismatch 63ffffffffffffffffffffffffffffffffffffff" out ' +_bz='\0' +_bz5="$_bz$_bz$_bz$_bz$_bz" +_bz20="$_bz5$_bz5$_bz5$_bz5" + +test_expect_success 'fsck notices blob entry pointing to null sha1' ' + (git init null-blob && + cd null-blob && + sha=$(printf "100644 file$_bz$_bz20" | + git hash-object -w --stdin -t tree) && + git fsck 2>out && + cat out && + grep "warning.*null sha1" out + ) +' + +test_expect_success 'fsck notices submodule entry pointing to null sha1' ' + (git init null-commit && + cd null-commit && + sha=$(printf "160000 submodule$_bz$_bz20" | + git hash-object -w --stdin -t tree) && + git fsck 2>out && + cat out && + grep "warning.*null sha1" out + ) +' + test_done -- 2.26.2