From: Jeff King <peff@peff.net>
To: Eric Sunshine <sunshine@sunshineco.com>
Cc: Git List <git@vger.kernel.org>
Subject: Re: [PATCH 07/18] convert trivial cases to FLEX_ARRAY macros
Date: Mon, 15 Feb 2016 23:22:22 -0500 [thread overview]
Message-ID: <20160216042222.GA27060@sigill.intra.peff.net> (raw)
In-Reply-To: <CAPig+cQOF7CsJNoiu8FAMk+csrOWG2dbEyxqfpWNwvGdUsjxcw@mail.gmail.com>
On Mon, Feb 15, 2016 at 11:18:56PM -0500, Eric Sunshine wrote:
> > diff --git a/builtin/reflog.c b/builtin/reflog.c
> > @@ -408,13 +407,12 @@ static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
> > reflog_expire_cfg_tail = &reflog_expire_cfg;
> >
> > for (ent = reflog_expire_cfg; ent; ent = ent->next)
> > - if (ent->len == len &&
> > - !memcmp(ent->pattern, pattern, len))
> > + if (!strncmp(ent->pattern, pattern, len) &&
> > + ent->pattern[len] == '\0')
>
> If 'ent->pattern' is shorter than 'pattern' then the strncmp() will
> fail, thus it will short-circuit before ent->pattern[len] has a chance
> to access beyond the end of memory allocated for 'ent->pattern'. Okay,
> makes sense.
Yeah. It took me a minute to convince myself that this was correct. If
you have a shorter or more clear way of writing it, I'm open to it. The
best I could come up with is running an extra "strlen" and otherwise
keeping the loop as it is; the performance on that is not as good, but
if performance is a concern, maybe something besides a linear search
would be in order. :)
-Peff
next prev parent reply other threads:[~2016-02-16 4:22 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-15 21:45 [PATCH 0/18] hardening allocations against integer overflow Jeff King
2016-02-15 21:49 ` [PATCH 01/18] add helpers for detecting size_t overflow Jeff King
2016-02-15 21:49 ` [PATCH 02/18] tree-diff: catch integer overflow in combine_diff_path allocation Jeff King
2016-02-15 21:50 ` [PATCH 03/18] harden REALLOC_ARRAY and xcalloc against size_t overflow Jeff King
2016-02-15 21:50 ` [PATCH 04/18] add helpers for allocating flex-array structs Jeff King
2016-02-16 1:47 ` Eric Sunshine
2016-02-16 2:52 ` Jeff King
2016-02-15 21:51 ` [PATCH 05/18] convert trivial cases to ALLOC_ARRAY Jeff King
2016-02-16 4:22 ` Eric Sunshine
2016-02-16 4:23 ` Jeff King
2016-02-16 4:32 ` Eric Sunshine
2016-02-16 5:46 ` Jeff King
2016-02-15 21:52 ` [PATCH 06/18] use xmallocz to avoid size arithmetic Jeff King
2016-02-15 21:52 ` [PATCH 07/18] convert trivial cases to FLEX_ARRAY macros Jeff King
2016-02-16 2:17 ` Eric Sunshine
2016-02-16 3:15 ` Jeff King
2016-02-16 3:26 ` Jeff King
2016-02-16 3:36 ` Jeff King
2016-02-16 4:18 ` Eric Sunshine
2016-02-16 4:22 ` Jeff King [this message]
2016-02-16 4:10 ` Eric Sunshine
2016-02-15 21:53 ` [PATCH 08/18] use st_add and st_mult for allocation size computation Jeff King
2016-02-16 5:47 ` Eric Sunshine
2016-02-15 21:53 ` [PATCH 09/18] write_untracked_extension: use FLEX_ALLOC helper Jeff King
2016-02-15 21:54 ` [PATCH 10/18] fast-import: simplify allocation in start_packfile Jeff King
2016-02-15 21:54 ` [PATCH 11/18] fetch-pack: simplify add_sought_entry Jeff King
2016-02-15 21:55 ` [PATCH 12/18] test-path-utils: fix normalize_path_copy output buffer size Jeff King
2016-02-15 21:56 ` [PATCH 13/18] sequencer: simplify memory allocation of get_message Jeff King
2016-02-16 6:05 ` Eric Sunshine
2016-02-15 21:56 ` [PATCH 14/18] git-compat-util: drop mempcpy compat code Jeff King
2016-02-16 6:05 ` Eric Sunshine
2016-02-15 21:56 ` [PATCH 15/18] transport_anonymize_url: use xstrfmt Jeff King
2016-02-15 21:56 ` [PATCH 16/18] diff_populate_gitlink: use a strbuf Jeff King
2016-02-15 21:57 ` [PATCH 17/18] convert ewah/bitmap code to use xmalloc Jeff King
2016-02-15 21:57 ` [PATCH 18/18] ewah: convert to REALLOC_ARRAY, etc Jeff King
2016-02-15 22:02 ` [PATCH 0/18] hardening allocations against integer overflow Jeff King
2016-02-19 11:19 ` [PATCH v2 0/21] " Jeff King
2016-02-19 11:21 ` [PATCH 01/21] reflog_expire_cfg: NUL-terminate pattern field Jeff King
2016-02-19 11:21 ` [PATCH 02/21] add helpers for detecting size_t overflow Jeff King
2016-02-19 11:21 ` [PATCH 03/21] tree-diff: catch integer overflow in combine_diff_path allocation Jeff King
2016-02-19 11:22 ` [PATCH 04/21] harden REALLOC_ARRAY and xcalloc against size_t overflow Jeff King
2016-02-20 21:32 ` René Scharfe
2016-02-21 23:30 ` Jeff King
2016-02-19 11:22 ` [PATCH 05/21] add helpers for allocating flex-array structs Jeff King
2016-02-19 11:23 ` [PATCH 06/21] convert manual allocations to argv_array Jeff King
2016-02-20 8:07 ` Eric Sunshine
2016-02-20 8:10 ` Jeff King
2016-02-20 8:29 ` Eric Sunshine
2016-02-20 8:34 ` Jeff King
2016-02-20 8:39 ` Eric Sunshine
2016-02-20 8:57 ` Jeff King
2016-02-20 9:04 ` Eric Sunshine
2016-02-19 11:23 ` [PATCH 07/21] convert trivial cases to ALLOC_ARRAY Jeff King
2016-02-19 11:23 ` [PATCH 08/21] use xmallocz to avoid size arithmetic Jeff King
2016-02-19 11:23 ` [PATCH 09/21] convert trivial cases to FLEX_ARRAY macros Jeff King
2016-02-19 11:23 ` [PATCH 10/21] use st_add and st_mult for allocation size computation Jeff King
2016-02-19 11:24 ` [PATCH 11/21] prepare_{git,shell}_cmd: use argv_array Jeff King
2016-02-19 11:24 ` [PATCH 12/21] write_untracked_extension: use FLEX_ALLOC helper Jeff King
2016-02-19 11:24 ` [PATCH 13/21] fast-import: simplify allocation in start_packfile Jeff King
2016-02-19 17:48 ` Junio C Hamano
2016-02-19 19:12 ` Jeff King
2016-02-19 11:24 ` [PATCH 14/21] fetch-pack: simplify add_sought_entry Jeff King
2016-02-19 11:24 ` [PATCH 15/21] test-path-utils: fix normalize_path_copy output buffer size Jeff King
2016-02-19 11:25 ` [PATCH 16/21] sequencer: simplify memory allocation of get_message Jeff King
2016-02-19 11:25 ` [PATCH 17/21] git-compat-util: drop mempcpy compat code Jeff King
2016-02-19 11:25 ` [PATCH 18/21] transport_anonymize_url: use xstrfmt Jeff King
2016-02-19 11:25 ` [PATCH 19/21] diff_populate_gitlink: use a strbuf Jeff King
2016-02-19 11:25 ` [PATCH 20/21] convert ewah/bitmap code to use xmalloc Jeff King
2016-02-19 11:25 ` [PATCH 21/21] ewah: convert to REALLOC_ARRAY, etc Jeff King
2016-02-22 22:41 ` [PATCH v3 0/22] hardening allocations against integer overflow Jeff King
2016-02-22 22:43 ` [PATCH v3 01/22] reflog_expire_cfg: NUL-terminate pattern field Jeff King
2016-02-22 22:43 ` [PATCH v3 02/22] add helpers for detecting size_t overflow Jeff King
2016-02-22 22:43 ` [PATCH v3 03/22] tree-diff: catch integer overflow in combine_diff_path allocation Jeff King
2016-02-22 22:43 ` [PATCH v3 04/22] harden REALLOC_ARRAY and xcalloc against size_t overflow Jeff King
2016-02-22 22:43 ` [PATCH v3 05/22] add helpers for allocating flex-array structs Jeff King
2016-02-22 22:44 ` [PATCH v3 06/22] argv-array: add detach function Jeff King
2016-02-22 22:44 ` [PATCH v3 07/22] convert manual allocations to argv_array Jeff King
2016-02-22 22:44 ` [PATCH v3 08/22] convert trivial cases to ALLOC_ARRAY Jeff King
2016-02-22 22:44 ` [PATCH v3 09/22] use xmallocz to avoid size arithmetic Jeff King
2016-02-22 22:44 ` [PATCH v3 10/22] convert trivial cases to FLEX_ARRAY macros Jeff King
2016-02-22 22:44 ` [PATCH v3 11/22] use st_add and st_mult for allocation size computation Jeff King
2016-02-22 22:44 ` [PATCH v3 12/22] prepare_{git,shell}_cmd: use argv_array Jeff King
2016-02-22 22:44 ` [PATCH v3 13/22] write_untracked_extension: use FLEX_ALLOC helper Jeff King
2016-02-22 22:44 ` [PATCH v3 14/22] fast-import: simplify allocation in start_packfile Jeff King
2016-02-22 22:44 ` [PATCH v3 15/22] fetch-pack: simplify add_sought_entry Jeff King
2016-02-22 22:44 ` [PATCH v3 16/22] test-path-utils: fix normalize_path_copy output buffer size Jeff King
2016-02-22 22:44 ` [PATCH v3 17/22] sequencer: simplify memory allocation of get_message Jeff King
2016-02-22 22:45 ` [PATCH v3 18/22] git-compat-util: drop mempcpy compat code Jeff King
2016-02-22 22:45 ` [PATCH v3 19/22] transport_anonymize_url: use xstrfmt Jeff King
2016-02-22 22:45 ` [PATCH v3 20/22] diff_populate_gitlink: use a strbuf Jeff King
2016-02-22 22:45 ` [PATCH v3 21/22] convert ewah/bitmap code to use xmalloc Jeff King
2016-02-22 22:45 ` [PATCH v3 22/22] ewah: convert to REALLOC_ARRAY, etc Jeff King
2016-02-22 23:08 ` [PATCH v3 0/22] hardening allocations against integer overflow Junio C Hamano
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