git-commit-vandalism/t/t4141-apply-too-large.sh

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apply: reject patches larger than ~1 GiB The apply code is not prepared to handle extremely large files. It uses "int" in some places, and "unsigned long" in others. This combination leads to unfortunate problems when switching between the two types. Using "int" prevents us from handling large files, since large offsets will wrap around and spill into small negative values, which can result in wrong behavior (like accessing the patch buffer with a negative offset). Converting from "unsigned long" to "int" also has truncation problems even on LLP64 platforms where "long" is the same size as "int", since the former is unsigned but the latter is not. To avoid potential overflow and truncation issues in `git apply`, apply similar treatment as in dcd1742e56 (xdiff: reject files larger than ~1GB, 2015-09-24), where the xdiff code was taught to reject large files for similar reasons. The maximum size was chosen somewhat arbitrarily, but picking a value just shy of a gigabyte allows us to double it without overflowing 2^31-1 (after which point our value would wrap around to a negative number). To give ourselves a bit of extra margin, the maximum patch size is a MiB smaller than a full GiB, which gives us some slop in case we allocate "(records + 1) * sizeof(int)" or similar. Luckily, the security implications of these conversion issues are relatively uninteresting, because a victim needs to be convinced to apply a malicious patch. Reported-by: 정재우 <thebound7@gmail.com> Suggested-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-25 20:24:31 +02:00
#!/bin/sh
test_description='git apply with too-large patch'
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
test_expect_success EXPENSIVE 'git apply rejects patches that are too large' '
sz=$((1024 * 1024 * 1023)) &&
{
cat <<-\EOF &&
diff --git a/file b/file
new file mode 100644
--- /dev/null
+++ b/file
@@ -0,0 +1 @@
EOF
test-tool genzeros
} | test_copy_bytes $sz | test_must_fail git apply 2>err &&
grep "git apply: failed to read" err
'
test_done