[PATCH] fix "git apply --index ..." not to deref NULL
- From
Jim Meyering <jim@meyering.net>
- Date
- Oct 12, 2011, 08:18 UTC
- Message-ID
- <87lisq8vye.fsf@rho.meyering.net>
I noticed this when "git am CORRUPTED" unexpectedly failed with an odd diagnostic, and even removed one of the files it was supposed to have patched.
Reproduce with any valid old/new patch from which you have removed the "+++ b/FILE" line. You'll see a diagnostic like this
fatal: unable to write file '(null)' mode 100644: Bad address
and you'll find that FILE has been removed.
The above is on glibc-based systems. On other systems, rather than getting "null" in parentheses, you'll probably provoke a segfault, as git tries to dereference the NULL file name.
Signed-off-by: Jim Meyering <meyering@redhat.com> --- builtin/apply.c | 3 +++ t/t4254-am-corrupt.sh | 43 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 46 insertions(+), 0 deletions(-) create mode 100644 t/t4254-am-corrupt.sh
diff --git a/builtin/apply.c b/builtin/apply.c index f2edc52..aaa39fe 100644 --- a/builtin/apply.c +++ b/builtin/apply.c @@ -1407,6 +1407,9 @@ static int find_header(char *line, unsigned long size, int *hdrsize, struct patc "%d leading pathname components (line %d)" , p_value, linenr); patch->old_name = patch->new_name = patch->def_name; } + if (!patch->is_delete && !patch->new_name) + die("git diff header lacks filename information " + "(line %d)", linenr); patch->is_toplevel_relative = 1; *hdrsize = git_hdr_len; return offset; diff --git a/t/t4254-am-corrupt.sh b/t/t4254-am-corrupt.sh new file mode 100644 index 0000000..b7da95f --- /dev/null +++ b/t/t4254-am-corrupt.sh @@ -0,0 +1,43 @@ +#!/bin/sh + +test_description='git am with corrupt input' +. ./test-lib.sh + +# Note the missing "+++" line: +cat > bad-patch.diff <<'EOF' +From: A U Thor <au.thor@example.com> +diff --git a/f b/f +index 7898192..6178079 100644 +--- a/f +@@ -1 +1 @@ +-a ++b +EOF + +test_expect_success setup ' + test $? = 0 && + echo a > f && + git add f && + test_tick && + git commit -m initial +' + +# This used to fail before, too, but with a different diagnostic. +# fatal: unable to write file '(null)' mode 100644: Bad address +# Also, it had the unwanted side-effect of deleting f. +test_expect_success 'try to apply corrupted patch' ' + git am bad-patch.diff 2> actual + test $? = 1 +' + +cat > expected <<EOF +fatal: git diff header lacks filename information (line 4) +EOF + +test_expect_success 'compare diagnostic; ensure file is still here' ' + test $? = 0 && + test -f f && + test_cmp expected actual +' + +test_done -- 1.7.7