diff options
authorJohannes Schindelin <>2019-09-12 12:54:05 (GMT)
committerJohannes Schindelin <>2019-12-04 12:20:05 (GMT)
commite1d911dd4c7b76a5a8cec0f5c8de15981e34da83 (patch)
parent0060fd1511b94c918928fa3708f69a3f33895a4a (diff)
mingw: disallow backslash characters in tree objects' file names
The backslash character is not a valid part of a file name on Windows. Hence it is dangerous to allow writing files that were unpacked from tree objects, when the stored file name contains a backslash character: it will be misinterpreted as directory separator. This not only causes ambiguity when a tree contains a blob `a\b` and a tree `a` that contains a blob `b`, but it also can be used as part of an attack vector to side-step the careful protections against writing into the `.git/` directory during a clone of a maliciously-crafted repository. Let's prevent that, addressing CVE-2019-1354. Note: we guard against backslash characters in tree objects' file names _only_ on Windows (because on other platforms, even on those where NTFS volumes can be mounted, the backslash character is _not_ a directory separator), and _only_ when `core.protectNTFS = true` (because users might need to generate tree objects for other platforms, of course without touching the worktree, e.g. using `git update-index --cacheinfo`). Signed-off-by: Johannes Schindelin <>
4 files changed, 13 insertions, 3 deletions
diff --git a/t/ b/t/
index cb4b66e..33c955f 100755
--- a/t/
+++ b/t/
@@ -419,6 +419,7 @@ while read name path pretty; do
git init $name-$type &&
cd $name-$type &&
+ git config core.protectNTFS false &&
echo content >file &&
git add file &&
git commit -m base &&
diff --git a/t/ b/t/
index e1cd0a3..7c65e7a 100755
--- a/t/
+++ b/t/
@@ -89,16 +89,18 @@ test_expect_success MINGW 'prevent git~1 squatting on Windows' '
git hash-object -w --stdin)" &&
rev="$(git rev-parse --verify HEAD)" &&
hash="$(echo x | git hash-object -w --stdin)" &&
- git update-index --add \
+ git -c core.protectNTFS=false update-index --add \
--cacheinfo 100644,$modules,.gitmodules \
--cacheinfo 160000,$rev,c \
--cacheinfo 160000,$rev,d\\a \
--cacheinfo 100644,$hash,d./a/x \
--cacheinfo 100644,$hash,d./a/..git &&
test_tick &&
- git commit -m "module"
+ git -c core.protectNTFS=false commit -m "module" &&
+ test_must_fail git show HEAD: 2>err &&
+ test_i18ngrep backslash err
) &&
- test_must_fail git \
+ test_must_fail git -c core.protectNTFS=false \
clone --recurse-submodules squatting squatting-clone 2>err &&
test_i18ngrep "directory not empty" err &&
! grep gitdir squatting-clone/d/a/git~2
diff --git a/t/ b/t/
index 866ddf6..e606207 100755
--- a/t/
+++ b/t/
@@ -421,6 +421,7 @@ test_expect_success 'directory becomes symlink' '
test_expect_success 'fast-export quotes pathnames' '
git init crazy-paths &&
+ test_config -C crazy-paths core.protectNTFS false &&
(cd crazy-paths &&
blob=$(echo foo | git hash-object -w --stdin) &&
git update-index --add \
diff --git a/tree-walk.c b/tree-walk.c
index d459fed..54ff959 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -41,6 +41,12 @@ static int decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned l
strbuf_addstr(err, _("empty filename in tree entry"));
return -1;
+ if (protect_ntfs && strchr(path, '\\')) {
+ strbuf_addf(err, _("filename in tree entry contains backslash: '%s'"), path);
+ return -1;
+ }
len = strlen(path) + 1;
/* Initialize the descriptor entry */