on Thu Jan 29 2009, Jeff King <peff-AT-peff.net> wrote:
> On Thu, Jan 29, 2009 at 12:20:41AM -0500, Jeff King wrote:
>
>> Ok, that _is_ big. ;) I wouldn't be surprised if there is some corner of
>> the code that barfs on a single object that doesn't fit in a signed
>> 32-bit integer; I don't think we have any test coverage for stuff that
>> big.
>
> Sure enough, that is the problem. With the patch below I was able to
> "git add" and commit a 3 gigabyte file of random bytes (so even the
> deflated object was 3G).
>
> I think it might be worth applying as a general cleanup, but I have no
> idea if other parts of the system might barf on such an object.
>
> -- >8 --
> Subject: [PATCH] avoid 31-bit truncation in write_loose_object
>
> The size of the content we are adding may be larger than
> 2.1G (i.e., "git add gigantic-file"). Most of the code-path
> to do so uses size_t or unsigned long to record the size,
> but write_loose_object uses a signed int.
>
> On platforms where "int" is 32-bits (which includes x86_64
> Linux platforms), we end up passing malloc a negative size.
Good work. I don't know if this matters to you, but I think on a 32-bit
platform you'll find that size_t, which is supposed to be able to hold
the size of the largest representable *memory block*, is only 4 bytes
large:
#include <limits.h>
#include <stdio.h>
int main()
{
printf("sizeof(size_t) = %d", sizeof(size_t));
}
Prints "sizeof(size_t) = 4" on my core duo.
> Signed-off-by: Jeff King <peff@xxxxxxxx>
> ---
> sha1_file.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/sha1_file.c b/sha1_file.c
> index 360f7e5..8868b80 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -2340,7 +2340,8 @@ static int create_tmpfile(char *buffer, size_t bufsiz, const
> char *filename)
> static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
> void *buf, unsigned long len, time_t mtime)
> {
> - int fd, size, ret;
> + int fd, ret;
> + size_t size;
> unsigned char *compressed;
> z_stream stream;
> char *filename;
--
Dave Abrahams
BoostPro Computing
http://www.boostpro.com
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