[hackers] [ubase] [PATCH] dd: Avoid VLA based on user-specified value

[Michael Forney]

---
 dd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dd.c b/dd.c
index 2dce98e..123cb47 100644
--- a/dd.c
+++ b/dd.c
@@ -126,14 +126,16 @@ prepare_copy(struct dd_config *ddc, int *ifd, int *ofd)
        }
 
        if (lseek(*ifd, ddc->skip, SEEK_CUR) < 0) {
-               char buffer[ddc->bs];
+               char *buffer = emalloc(ddc->bs);
                for (uint64_t i = 0; i < ddc->skip; i += ddc->bs) {
                        if (read(*ifd, &buffer, ddc->bs) < 0) {
                                errno = EINVAL;
                                close(*ifd);
+                               free(buffer);
                                return -1;
                        }
                }
+               free(buffer);
        }
        lseek(*ofd, ddc->seek, SEEK_CUR);
        posix_fadvise(*ifd, ddc->skip, 0, POSIX_FADV_SEQUENTIAL);
-- 
2.20.1