Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH] ovl: Use "buf" flexible array for memcpy() destination | Date | Sat, 24 Sep 2022 00:33:15 -0700 |
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The "buf" flexible array needs to be the memcpy() destination to avoid false positive run-time warning from the recent FORTIFY_SOURCE hardening:
memcpy: detected field-spanning write (size 93) of single field "&fh->fb" at fs/overlayfs/export.c:799 (size 21)
Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: linux-unionfs@vger.kernel.org Reported-by: syzbot+9d14351a171d0d1c7955@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/000000000000763a6c05e95a5985@google.com/ Signed-off-by: Kees Cook <keescook@chromium.org> --- fs/overlayfs/export.c | 2 +- fs/overlayfs/overlayfs.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index e065a5b9a442..ac9c3ad04016 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -796,7 +796,7 @@ static struct ovl_fh *ovl_fid_to_fh(struct fid *fid, int buflen, int fh_type) return ERR_PTR(-ENOMEM); /* Copy unaligned inner fh into aligned buffer */ - memcpy(&fh->fb, fid, buflen - OVL_FH_WIRE_OFFSET); + memcpy(fh->buf, fid, buflen - OVL_FH_WIRE_OFFSET); return fh; } diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 87759165d32b..a0e450313ea4 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -108,7 +108,7 @@ struct ovl_fh { u8 padding[3]; /* make sure fb.fid is 32bit aligned */ union { struct ovl_fb fb; - u8 buf[0]; + DECLARE_FLEX_ARRAY(u8, buf); }; } __packed; -- 2.34.1
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