| Message ID | 20240123002814.1396804-67-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
diff --git a/fs/ocfs2/resize.c b/fs/ocfs2/resize.c index d65d43c61857..5cc83e1d54a7 100644 --- a/fs/ocfs2/resize.c +++ b/fs/ocfs2/resize.c @@ -423,7 +423,7 @@ static int ocfs2_verify_group_and_input(struct inode *inode, else if (next_free != cl_count && next_free != input->chain) mlog(ML_ERROR, "the add group should be in chain %u\n", next_free); - else if (total_clusters + input->clusters < total_clusters) + else if (add_would_overflow(total_clusters, input->clusters)) mlog(ML_ERROR, "add group's clusters overflow.\n"); else if (input->clusters > cl_cpg) mlog(ML_ERROR, "the cluster exceeds the maximum of a group\n");
In an effort to separate intentional arithmetic wrap-around from unexpected wrap-around, we need to refactor places that depend on this kind of math. One of the most common code patterns of this is: VAR + value < VAR Notably, this is considered "undefined behavior" for signed and pointer types, which the kernel works around by using the -fno-strict-overflow option in the build[1] (which used to just be -fwrapv). Regardless, we want to get the kernel source to the position where we can meaningfully instrument arithmetic wrap-around conditions and catch them when they are unexpected, regardless of whether they are signed[2], unsigned[3], or pointer[4] types. Refactor open-coded wrap-around addition test to use add_would_overflow(). This paves the way to enabling the wrap-around sanitizers in the future. Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] Link: https://github.com/KSPP/linux/issues/26 [2] Link: https://github.com/KSPP/linux/issues/27 [3] Link: https://github.com/KSPP/linux/issues/344 [4] Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: ocfs2-devel@lists.linux.dev Signed-off-by: Kees Cook <keescook@chromium.org> --- fs/ocfs2/resize.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)