xsize_t() checks if an off_t argument can be safely converted to
a size_t return value.  If the check is executed too early, it could
fail for large files on 32-bit architectures even if the size_t code
path is not taken.  Other paths might be able to handle the large file.
Specifically, index_stream_convert_blob() is able to handle a large file
if a filter is configured that returns a small result.

Signed-off-by: Steffen Prohaska <proha...@zib.de>
---

This patch should be applied on top of sp/stream-clean-filter.

index_stream() might internally also be able to handle large files to
some extent.  But it uses size_t for its third argument, and we must
already die() when calling it.  It might be a good idea to convert its
interface to use off_t and push the size checks further down the stack.
In general, it might be good idea to carefully consider whether to use
off_t or size_t when passing file-related sizes around.  To me it looks
like a separate issue for a separate patch series (I have no specific
plans to prepare one).

 sha1_file.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index 5b0e67a..6f18c22 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -3180,17 +3180,22 @@ int index_fd(unsigned char *sha1, int fd, struct stat 
*st,
             enum object_type type, const char *path, unsigned flags)
 {
        int ret;
-       size_t size = xsize_t(st->st_size);
 
+       /*
+        * Call xsize_t() only when needed to avoid potentially unnecessary
+        * die() for large files.
+        */
        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
                ret = index_stream_convert_blob(sha1, fd, path, flags);
        else if (!S_ISREG(st->st_mode))
                ret = index_pipe(sha1, fd, type, path, flags);
-       else if (size <= big_file_threshold || type != OBJ_BLOB ||
+       else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
                 (path && would_convert_to_git(path)))
-               ret = index_core(sha1, fd, size, type, path, flags);
+               ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
+                                flags);
        else
-               ret = index_stream(sha1, fd, size, type, path, flags);
+               ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
+                                  flags);
        close(fd);
        return ret;
 }
-- 
2.1.0.139.g351b19f

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