On 04/06/2017 10:34 AM, Jeff King wrote:
> On Thu, Apr 06, 2017 at 10:02:22AM +0200, Martin Liška wrote:
>
>> Subject: [PATCH 1/2] Fix nonnull errors reported by UBSAN with GCC 7.
>>
>> Memory functions like memmove and memcpy should not be called
>> with an argument equal to NULL.
>
> Yeah, makes sense. Your fixes are obviously correct. In other cases
> we've added wrappers like sane_qsort() that do the size check
> automatically. I'm not sure if we'd want to do the same here.
>
> Either way, it probably makes sense to take this as a quick fix and
> worry about refactoring as a possible patch on top.
>
> Thanks.
>
> -Peff
>
Hello.
I'm sending (v2), where I updated commit message and wrapped 2 problematic
places to newly introduced macros that do the check. Follow-up patch can
change usages of memcpy and memove.
Martin
>From 876cfa4f4b2e74d43b9fd93d1056b88ab2ace0cd Mon Sep 17 00:00:00 2001
From: marxin <mliska@xxxxxxx>
Date: Wed, 5 Apr 2017 14:31:32 +0200
Subject: [PATCH 1/2] Fix nonnull errors reported by UBSAN with GCC 7.
Memory functions like memmove and memcpy should not be called
with an argument equal to NULL.
Signed-off-by: Martin Liska <mliska@xxxxxxx>
---
apply.c | 6 +++---
builtin/ls-files.c | 2 +-
git-compat-util.h | 20 ++++++++++++++++++++
3 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/apply.c b/apply.c
index e6dbab26a..eacca29fa 100644
--- a/apply.c
+++ b/apply.c
@@ -2802,9 +2802,9 @@ static void update_image(struct apply_state *state,
img->line + applied_pos + preimage_limit,
(img->nr - (applied_pos + preimage_limit)) *
sizeof(*img->line));
- memcpy(img->line + applied_pos,
- postimage->line,
- postimage->nr * sizeof(*img->line));
+ MEMCPY(img->line + applied_pos,
+ postimage->line,
+ postimage->nr * sizeof(*img->line));
if (!state->allow_overlap)
for (i = 0; i < postimage->nr; i++)
img->line[applied_pos + i].flag |= LINE_PATCHED;
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index d449e46db..7caeeb6a6 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -391,7 +391,7 @@ static void prune_cache(const char *prefix, size_t prefixlen)
}
last = next;
}
- memmove(active_cache, active_cache + pos,
+ MEMMOVE(active_cache, active_cache + pos,
(last - pos) * sizeof(struct cache_entry *));
active_nr = last - pos;
}
diff --git a/git-compat-util.h b/git-compat-util.h
index 8a4a3f85e..e5323f6c7 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -1002,6 +1002,26 @@ int git_qsort_s(void *base, size_t nmemb, size_t size,
die("BUG: qsort_s() failed"); \
} while (0)
+static inline void *sane_memcpy(void *dest, const void *src, size_t n)
+{
+ if (n > 0)
+ return memcpy(dest, src, n);
+ else
+ return dest;
+}
+
+#define MEMCPY(dest, src, n) sane_memcpy(dest, src, n)
+
+static inline void *sane_memmove(void *dest, const void *src, size_t n)
+{
+ if (n > 0)
+ return memmove(dest, src, n);
+ else
+ return dest;
+}
+
+#define MEMMOVE(dest, src, n) sane_memmove(dest, src, n)
+
#ifndef REG_STARTEND
#error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd"
#endif
--
2.12.2