I hope this fixes a Luke Dashjr coreutils bug report about ext4 ramdisks; see “9.1: du Aborted (corrupt filesystem)” <https://debbugs.gnu.org/59821>. * lib/fts.c (fts_build): Fix two bugs. First, fts_stat was being called without checking its return value, causing a later abort. Second, there was a race between opening a directory and statting it, fixed by using fstat on the file descriptor rather than fstatat on the directory name. --- ChangeLog | 10 ++++++++++ lib/fts.c | 32 ++++++++++++++++++++++++-------- 2 files changed, 34 insertions(+), 8 deletions(-)
diff --git a/ChangeLog b/ChangeLog index 54e3a23457..feab2d6ca4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,15 @@ 2022-12-06 Paul Eggert <egg...@cs.ucla.edu> + fts: fix race + mishandling of fstatat failure + I hope this fixes a Luke Dashjr coreutils bug report about ext4 + ramdisks; see “9.1: du Aborted (corrupt filesystem)” + <https://debbugs.gnu.org/59821>. + * lib/fts.c (fts_build): Fix two bugs. First, fts_stat was being + called without checking its return value, causing a later abort. + Second, there was a race between opening a directory and statting + it, fixed by using fstat on the file descriptor rather than + fstatat on the directory name. + fts: omit goto break_without_closedir * lib/fts.c (fts_build): Refactor to omit goto. diff --git a/lib/fts.c b/lib/fts.c index 27354d39c8..74a08f7ec8 100644 --- a/lib/fts.c +++ b/lib/fts.c @@ -1316,19 +1316,35 @@ fts_build (register FTS *sp, int type) /* Rather than calling fts_stat for each and every entry encountered in the readdir loop (below), stat each directory only right after opening it. */ - if (cur->fts_info == FTS_NSOK) - cur->fts_info = fts_stat(sp, cur, false); - else if (sp->fts_options & FTS_TIGHT_CYCLE_CHECK) - { - /* Now read the stat info again after opening a directory to + bool stat_optimization = cur->fts_info == FTS_NSOK; + + if (stat_optimization + /* Also read the stat info again after opening a directory to reveal eventual changes caused by a submount triggered by the traversal. But do it only for utilities which use FTS_TIGHT_CYCLE_CHECK. Therefore, only find and du benefit/suffer from this feature for now. */ - LEAVE_DIR (sp, cur, "4"); - fts_stat (sp, cur, false); - if (! enter_dir (sp, cur)) + || ISSET (FTS_TIGHT_CYCLE_CHECK)) + { + if (!stat_optimization) + LEAVE_DIR (sp, cur, "4"); + if (fstat (dir_fd, cur->fts_statp) != 0) + { + int fstat_errno = errno; + closedir_and_clear (cur->fts_dirp); + if (type == BREAD) + { + cur->fts_errno = fstat_errno; + cur->fts_info = FTS_NS; + } + __set_errno (fstat_errno); + return NULL; + } + if (stat_optimization) + cur->fts_info = FTS_D; + else if (! enter_dir (sp, cur)) { + closedir_and_clear (cur->fts_dirp); __set_errno (ENOMEM); return NULL; } -- 2.38.1
