@matheusbsbs / matheus-bagliano / commits / 72695d8214

mv: handle lstat() failure correctly

When moving a directory onto another with `git mv` various checks are performed. One of of these validates that the destination is not existing. When calling `lstat` on the destination path and it fails as the path doesn't exist, some environments seem to overwrite the passed in `stat` memory nonetheless (I observed this issue on debian 12 of x86_64, running on OrbStack on ARM, emulated with Rosetta). This would affect the code that followed as it would still acccess a now modified `st` structure, which now seems to contain uninitialized memory. `S_ISDIR(st_dir_mode)` would then typically return false causing the code to run into a bad case. The fix avoids overwriting the existing `st` structure, providing an alternative that exists only for that purpose. Note that this patch minimizes complexity instead of stack-frame size. Signed-off-by: Sebastian Thiel <sebastian.thiel@icloud.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Sebastian Thiel committed Aug 9, 2023 at 07:47 UTC 72695d8214791161a943086e894874b4fd71ba9f

2 files changed +9 -2

builtin/mv.c

+2 -2

index 665bd27448..5213d99381 100644 --- a/builtin/mv.c +++ b/builtin/mv.c @@ -183,7 +183,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix) int src_dir_nr = 0, src_dir_alloc = 0; struct strbuf a_src_dir = STRBUF_INIT; enum update_mode *modes, dst_mode = 0; - struct stat st; + struct stat st, dest_st; struct string_list src_for_dst = STRING_LIST_INIT_NODUP; struct lock_file lock_file = LOCK_INIT; struct cache_entry *ce; @@ -303,7 +303,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix) goto act_on_entry; } if (S_ISDIR(st.st_mode) - && lstat(dst, &st) == 0) { + && lstat(dst, &dest_st) == 0) { bad = _("cannot move directory over file"); goto act_on_entry; }

t/t7001-mv.sh

index 898a920532..f136ea76f7 100755 --- a/t/t7001-mv.sh +++ b/t/t7001-mv.sh @@ -174,6 +174,13 @@ test_expect_success 'do not move directory over existing directory' ' test_must_fail git mv path2 path0 ' +test_expect_success 'rename directory to non-existing directory' ' + mkdir dir-a && + >dir-a/f && + git add dir-a && + git mv dir-a non-existing-dir +' + test_expect_success 'move into "."' ' git mv path1/path2/ . '