diff options
| author | Piotr Pawel Stefaniak <pstef@FreeBSD.org> | 2021-09-05 16:59:08 +0000 |
|---|---|---|
| committer | Piotr Pawel Stefaniak <pstef@FreeBSD.org> | 2021-09-15 23:46:44 +0000 |
| commit | 2171b2cbe084118e0e8f7de658f0302d0feb8827 (patch) | |
| tree | b00191a993a8ebf6e4b11497e20db05c9e4d3dc3 | |
| parent | bcf2e78dc48378456798191f1c15cb76d6221a65 (diff) | |
| download | src-2171b2cbe084118e0e8f7de658f0302d0feb8827.tar.gz src-2171b2cbe084118e0e8f7de658f0302d0feb8827.zip | |
diff: avoid applying offsets to null pointer
This was the only instance of undefined behavior I could find so far.
| -rw-r--r-- | usr.bin/diff/diffreg.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/usr.bin/diff/diffreg.c b/usr.bin/diff/diffreg.c index c743c862f2d6..4a00aff9243b 100644 --- a/usr.bin/diff/diffreg.c +++ b/usr.bin/diff/diffreg.c @@ -255,7 +255,6 @@ diffreg(char *file1, char *file2, int flags, int capsicum) anychange = 0; lastline = 0; lastmatchline = 0; - context_vec_ptr = context_vec_start - 1; /* * hw excludes padding and make sure when -t is not used, @@ -1050,8 +1049,12 @@ proceed: /* * Allocate change records as needed. */ - if (context_vec_ptr == context_vec_end - 1) { - ptrdiff_t offset = context_vec_ptr - context_vec_start; + if (context_vec_start == NULL || + context_vec_ptr == context_vec_end - 1) { + ptrdiff_t offset = -1; + + if (context_vec_start != NULL) + offset = context_vec_ptr - context_vec_start; max_context <<= 1; context_vec_start = xreallocarray(context_vec_start, max_context, sizeof(*context_vec_start)); |