Few of us use git to compare or even version-control 2GB files,
but when we do, we'll want it to work.
Reading a recent patch, I noticed two lines like this:
int len = st.st_size;
Instead of "int", that should be "size_t". Otherwise, in the
non-symlink case, with 64-bit size_t, if the file's size is 2GB,
the following xmalloc will fail:
result = xmalloc(len + 1);
trying to allocate 2^64 - 2^31 + 1 bytes (assuming sign-extension
in the int-to-size_t promotion). And even if it didn't fail, the
subsequent "result[len] = 0;" would be equivalent to an unpleasant
"result[-2147483648] = 0;"
The other nearby "int"-declared size variable, sz, should also be of
type size_t, for the same reason. If sz ever wraps around and becomes
negative, xread will corrupt memory _before_ the "result" buffer.
Signed-off-by: Jim Meyering <jim@xxxxxxxxxxxx>
---
combine-diff.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/combine-diff.c b/combine-diff.c
index 6b7c6be..044633d 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -684,7 +684,7 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
goto deleted_file;
if (S_ISLNK(st.st_mode)) {
- int len = st.st_size;
+ size_t len = st.st_size;
result_size = len;
result = xmalloc(len + 1);
if (result_size != readlink(elem->path, result, len)) {
@@ -697,8 +697,8 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
}
else if (0 <= (fd = open(elem->path, O_RDONLY)) &&
!fstat(fd, &st)) {
- int len = st.st_size;
- int sz = 0;
+ size_t len = st.st_size;
+ size_t sz = 0;
elem->mode = canon_mode(st.st_mode);
result_size = len;
--
1.5.0.1.226.g7bd59
-
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