From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>,
"Johannes Schindelin" <Johannes.Schindelin@gmx.de>,
"Jeff King" <peff@peff.net>,
"Erik Faye-Lund" <kusmabite@gmail.com>,
"Jonathan Nieder" <jrnieder@gmail.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: [RFC PATCH 03/10] range-diff.c: use "size_t" to refer to "struct string_list"'s "nr"
Date: Thu, 9 Dec 2021 20:19:20 +0100 [thread overview]
Message-ID: <RFC-patch-03.10-183418f1223-20211209T191653Z-avarab@gmail.com> (raw)
In-Reply-To: <RFC-cover-00.10-00000000000-20211209T191653Z-avarab@gmail.com>
In a preceding commit the "nr" member of "struct string_list" was
changed to be "size_t" instead of an "unsigned int". Let's follow suit
here and do the same for our corresponding index variables.
We can also use the st_mult() helper again prepare the argument to
ALLOC_ARRAY(), but this time correctly as the "n" is unsigned. The
same goes for a new addition of "st_add()" for "a->nr + b->nr".
There was a segfault in range-diff.c and linear-assignment.c due to an
"int" overflow. This doesn't solve that problem, but on my system
moves it around a bit. Before this we'd segfault in the
"get_correspondences()" function in range-diff.c, specifically on this
line in the first loop in that function:
cost[i + n * j] = 0
Now we'll instead make it all the way into compute_assignment() called
by that same function, and segfault on line 37 of linear-assignment.c in:
if (COST(j, i1) > COST(j, i))
Which is defined as:
#define COST(column, row) cost[(column) + column_count * (row)]
And will overflow thusly, with a segfault as we try to use that as a
negative index into "cost":
(GDB) p j + column_count * i
$10 = -2147454537
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
range-diff.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/range-diff.c b/range-diff.c
index 170e8623313..41003033752 100644
--- a/range-diff.c
+++ b/range-diff.c
@@ -237,7 +237,7 @@ static int patch_util_cmp(const void *dummy, const struct patch_util *a,
static void find_exact_matches(struct string_list *a, struct string_list *b)
{
struct hashmap map = HASHMAP_INIT((hashmap_cmp_fn)patch_util_cmp, NULL);
- int i;
+ size_t i;
/* First, add the patches of a to a hash map */
for (i = 0; i < a->nr; i++) {
@@ -308,11 +308,11 @@ static int diffsize(const char *a, const char *b)
static void get_correspondences(struct string_list *a, struct string_list *b,
int creation_factor)
{
- int n = a->nr + b->nr;
+ size_t n = st_add(a->nr, b->nr);
int *cost, c, *a2b, *b2a;
- int i, j;
+ size_t i, j;
- ALLOC_ARRAY(cost, n * n);
+ ALLOC_ARRAY(cost, st_mult(n, n));
ALLOC_ARRAY(a2b, n);
ALLOC_ARRAY(b2a, n);
@@ -473,7 +473,7 @@ static void output(struct string_list *a, struct string_list *b,
{
struct strbuf buf = STRBUF_INIT, dashes = STRBUF_INIT;
int patch_no_width = decimal_width(1 + (a->nr > b->nr ? a->nr : b->nr));
- int i = 0, j = 0;
+ size_t i = 0, j = 0;
struct diff_options opts;
struct strbuf indent = STRBUF_INIT;
--
2.34.1.930.g0f9292b224d
next prev parent reply other threads:[~2021-12-09 19:19 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 19:19 [RFC PATCH 00/10] range-diff: fix segfault due to integer overflow Ævar Arnfjörð Bjarmason
2021-12-09 19:19 ` [RFC PATCH 01/10] string-list API: change "nr" and "alloc" to "size_t" Ævar Arnfjörð Bjarmason
2021-12-09 19:19 ` [RFC PATCH 02/10] range-diff.c: don't use st_mult() for signed "int" Ævar Arnfjörð Bjarmason
2021-12-10 3:39 ` Jeff King
2021-12-10 10:22 ` Ævar Arnfjörð Bjarmason
2021-12-10 11:41 ` Jeff King
2021-12-10 12:31 ` Ævar Arnfjörð Bjarmason
2021-12-10 19:24 ` Phillip Wood
2021-12-14 14:34 ` Jeff King
2021-12-10 14:27 ` Johannes Schindelin
2021-12-10 14:58 ` Ævar Arnfjörð Bjarmason
2021-12-11 14:01 ` Johannes Schindelin
2021-12-12 17:44 ` Ævar Arnfjörð Bjarmason
2021-12-14 14:42 ` Jeff King
2021-12-09 19:19 ` Ævar Arnfjörð Bjarmason [this message]
2021-12-09 19:19 ` [RFC PATCH 04/10] range-diff: zero out elements in "cost" first Ævar Arnfjörð Bjarmason
2021-12-09 19:19 ` [RFC PATCH 05/10] linear-assignment.c: split up compute_assignment() function Ævar Arnfjörð Bjarmason
2021-12-09 19:19 ` [RFC PATCH 06/10] linear-assignment.c: take "size_t", not "int" for *_count Ævar Arnfjörð Bjarmason
2021-12-09 19:19 ` [RFC PATCH 07/10] linear-assignment.c: convert a macro to a "static inline" function Ævar Arnfjörð Bjarmason
2021-12-09 19:19 ` [RFC PATCH 08/10] linear-assignment.c: detect signed add/mul on GCC and Clang Ævar Arnfjörð Bjarmason
2021-12-10 3:56 ` Jeff King
2021-12-09 19:19 ` [RFC PATCH 09/10] linear-assignment.c: add and use intprops.h from Gnulib Ævar Arnfjörð Bjarmason
2021-12-09 19:19 ` [RFC PATCH 10/10] linear-assignment.c: use "intmax_t" instead of "int" Ævar Arnfjörð Bjarmason
2021-12-10 4:00 ` Jeff King
2021-12-10 12:30 ` [RFC PATCH v2 0/5] range-diff: fix segfault due to integer overflow Ævar Arnfjörð Bjarmason
2021-12-10 12:30 ` [RFC PATCH v2 1/5] range-diff: zero out elements in "cost" first Ævar Arnfjörð Bjarmason
2021-12-14 13:36 ` Jeff King
2021-12-10 12:30 ` [RFC PATCH v2 2/5] linear-assignment.c: split up compute_assignment() function Ævar Arnfjörð Bjarmason
2021-12-14 13:39 ` Jeff King
2021-12-10 12:30 ` [RFC PATCH v2 3/5] linear-assignment.c: take "size_t", not "int" for *_count Ævar Arnfjörð Bjarmason
2021-12-14 13:40 ` Jeff King
2021-12-10 12:30 ` [RFC PATCH v2 4/5] range-diff.c: rename "n" to "column_count" in get_correspondences() Ævar Arnfjörð Bjarmason
2021-12-14 13:42 ` Jeff King
2021-12-10 12:30 ` [RFC PATCH v2 5/5] range-diff: fix integer overflow & segfault on cost[i + n * j] Ævar Arnfjörð Bjarmason
2021-12-14 14:04 ` Jeff King
2021-12-10 14:31 ` [RFC PATCH 00/10] range-diff: fix segfault due to integer overflow Johannes Schindelin
2021-12-10 15:07 ` Ævar Arnfjörð Bjarmason
2021-12-21 23:22 ` Philip Oakley
2021-12-21 23:36 ` Ævar Arnfjörð Bjarmason
2021-12-22 20:50 ` Johannes Schindelin
2021-12-22 21:11 ` Jeff King
2021-12-24 11:15 ` Philip Oakley
2021-12-24 16:46 ` Ævar Arnfjörð Bjarmason
2021-12-24 18:31 ` Philip Oakley
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