From a98b26588b683eb024ab81f3bb3549c43acd5188 Mon Sep 17 00:00:00 2001 From: jwalch Date: Fri, 15 Oct 2021 19:03:17 -0400 Subject: [PATCH] Avoid NULL+X UB in bss_mem.c Fixes #16816 Reviewed-by: Matt Caswell Reviewed-by: Bernd Edlinger Reviewed-by: Tomas Mraz (Merged from https://github.com/openssl/openssl/pull/16818) --- crypto/bio/bss_mem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/crypto/bio/bss_mem.c b/crypto/bio/bss_mem.c index 7e501762bb0..9153c1f1cd8 100644 --- a/crypto/bio/bss_mem.c +++ b/crypto/bio/bss_mem.c @@ -254,7 +254,7 @@ static long mem_ctrl(BIO *b, int cmd, long num, void *ptr) bm = bbm->readp; bo = bbm->buf; } - off = bm->data - bo->data; + off = (bm->data == bo->data) ? 0 : bm->data - bo->data; remain = bm->length; switch (cmd) { @@ -277,7 +277,7 @@ static long mem_ctrl(BIO *b, int cmd, long num, void *ptr) if (num < 0 || num > off + remain) return -1; /* Can't see outside of the current buffer */ - bm->data = bo->data + num; + bm->data = (num != 0) ? bo->data + num : bo->data; bm->length = bo->length - num; bm->max = bo->max - num; off = num; -- 2.47.2