All of lore.kernel.org
 help / color / mirror / Atom feed
From: Stefan O'Rear <sorear@fastmail.com>
To: linux-mm@kvack.org, linux-riscv@lists.infradead.org
Cc: Eric Biederman <ebiederm@xmission.com>,
	Kees Cook <keescook@chromium.org>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Greg Ungerer <gerg@linux-m68k.org>,
	Waldemar Brodkorb <wbx@openadk.org>,
	Stefan O'Rear <sorear@fastmail.com>
Subject: [PATCH] binfmt_flat: Fix corruption when not offsetting data start
Date: Mon, 25 Mar 2024 23:20:37 -0400	[thread overview]
Message-ID: <20240326032037.2478816-1-sorear@fastmail.com> (raw)

Commit 04d82a6d0881 ("binfmt_flat: allow not offsetting data start")
introduced a RISC-V specific variant of the FLAT format which does not
allocate any space for the (obsolescent) array of shared library
pointers. However, it did not disable the code which initializes the
array, resulting in the corruption of sizeof(long) bytes before the DATA
segment, generally the end of the TEXT segment.

Use CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET to guard initialization the
shared library pointer region so that it will only be initialized if
space is reserved for it.

Fixes: 04d82a6d0881 ("binfmt_flat: allow not offsetting data start")
Signed-off-by: Stefan O'Rear <sorear@fastmail.com>
Tested-by: Waldemar Brodkorb <wbx@openadk.org>
---
 fs/binfmt_flat.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index c26545d71d39..70c2b68988f4 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -879,6 +879,7 @@ static int load_flat_binary(struct linux_binprm *bprm)
 	if (res < 0)
 		return res;
 
+#ifndef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET
 	/* Update data segment pointers for all libraries */
 	for (i = 0; i < MAX_SHARED_LIBS; i++) {
 		if (!libinfo.lib_list[i].loaded)
@@ -893,6 +894,7 @@ static int load_flat_binary(struct linux_binprm *bprm)
 				return -EFAULT;
 		}
 	}
+#endif
 
 	set_binfmt(&flat_format);
 
-- 
2.40.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Stefan O'Rear <sorear@fastmail.com>
To: linux-mm@kvack.org, linux-riscv@lists.infradead.org
Cc: Eric Biederman <ebiederm@xmission.com>,
	Kees Cook <keescook@chromium.org>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Greg Ungerer <gerg@linux-m68k.org>,
	Waldemar Brodkorb <wbx@openadk.org>,
	Stefan O'Rear <sorear@fastmail.com>
Subject: [PATCH] binfmt_flat: Fix corruption when not offsetting data start
Date: Mon, 25 Mar 2024 23:20:37 -0400	[thread overview]
Message-ID: <20240326032037.2478816-1-sorear@fastmail.com> (raw)

Commit 04d82a6d0881 ("binfmt_flat: allow not offsetting data start")
introduced a RISC-V specific variant of the FLAT format which does not
allocate any space for the (obsolescent) array of shared library
pointers. However, it did not disable the code which initializes the
array, resulting in the corruption of sizeof(long) bytes before the DATA
segment, generally the end of the TEXT segment.

Use CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET to guard initialization the
shared library pointer region so that it will only be initialized if
space is reserved for it.

Fixes: 04d82a6d0881 ("binfmt_flat: allow not offsetting data start")
Signed-off-by: Stefan O'Rear <sorear@fastmail.com>
Tested-by: Waldemar Brodkorb <wbx@openadk.org>
---
 fs/binfmt_flat.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index c26545d71d39..70c2b68988f4 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -879,6 +879,7 @@ static int load_flat_binary(struct linux_binprm *bprm)
 	if (res < 0)
 		return res;
 
+#ifndef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET
 	/* Update data segment pointers for all libraries */
 	for (i = 0; i < MAX_SHARED_LIBS; i++) {
 		if (!libinfo.lib_list[i].loaded)
@@ -893,6 +894,7 @@ static int load_flat_binary(struct linux_binprm *bprm)
 				return -EFAULT;
 		}
 	}
+#endif
 
 	set_binfmt(&flat_format);
 
-- 
2.40.1



             reply	other threads:[~2024-03-26  3:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-26  3:20 Stefan O'Rear [this message]
2024-03-26  3:20 ` [PATCH] binfmt_flat: Fix corruption when not offsetting data start Stefan O'Rear
2024-03-26  5:53 ` Damien Le Moal
2024-03-26  5:53   ` Damien Le Moal
2024-04-04  7:40 ` Greg Ungerer
2024-04-04  7:40   ` Greg Ungerer
2024-04-24 20:44 ` Alexandre Ghiti
2024-04-24 20:44   ` Alexandre Ghiti

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20240326032037.2478816-1-sorear@fastmail.com \
    --to=sorear@fastmail.com \
    --cc=damien.lemoal@wdc.com \
    --cc=ebiederm@xmission.com \
    --cc=gerg@linux-m68k.org \
    --cc=keescook@chromium.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=wbx@openadk.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.