diff --cc: integer overflow given a 2GB-or-larger file
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@meyering.net> Signed-off-by: Junio C Hamano <junkio@cox.net>
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@ -684,7 +684,7 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
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goto deleted_file;
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if (S_ISLNK(st.st_mode)) {
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int len = st.st_size;
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size_t len = st.st_size;
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result_size = len;
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result = xmalloc(len + 1);
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if (result_size != readlink(elem->path, result, len)) {
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@ -697,8 +697,8 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
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}
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else if (0 <= (fd = open(elem->path, O_RDONLY)) &&
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!fstat(fd, &st)) {
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int len = st.st_size;
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int sz = 0;
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size_t len = st.st_size;
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size_t sz = 0;
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elem->mode = canon_mode(st.st_mode);
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result_size = len;
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