threads / patch / 43759

patchDon't use memcpy when source and dest. buffers may overlap

Subject: [PATCH] Don't use memcpy when source and dest. buffers may overlap

## tl;dr

One message between Dec 11, 2006 and Dec 11, 2006. Diffs are folded; open one to read it.

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Jim Meyering· Dec 11, 2006, 18:06 UTC · lore

git-index-pack can call memcpy with overlapping source and destination buffers. The patch below makes it use memmove instead.

If you want to demonstrate a failure, add the following two lines
+               if (input_offset < input_len)
+                 abort ();

before the existing memcpy call (shown in the patch below), and then run this:

  (cd t; sh ./t5500-fetch-pack.sh)
Signed-off-by: Jim Meyering <jim@meyering.net>
---
 index-pack.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
Show changes to index-pack.c +1 −2
diff --git a/index-pack.c b/index-pack.c
index 8331d99..6d6c92b 100644
--- a/index-pack.c
+++ b/index-pack.c
@@ -96,7 +96,7 @@ static void flush(void)
 		if (output_fd >= 0)
 			write_or_die(output_fd, input_buffer, input_offset);
 		SHA1_Update(&input_ctx, input_buffer, input_offset);
-		memcpy(input_buffer, input_buffer + input_offset, input_len);
+		memmove(input_buffer, input_buffer + input_offset, input_len);
 		input_offset = 0;
 	}
 }
--

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