Commit 87a1b401 authored by Kees Cook's avatar Kees Cook Committed by ZhangPeng
Browse files

binfmt_flat: Fix corruption when not offsetting data start 

stable inclusion
from stable-v6.6.47
commit 49df34d2b7da9e57c839555a2f7877291ce45ad1
bugzilla: https://gitee.com/openeuler/kernel/issues/IAHMJO

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=49df34d2b7da9e57c839555a2f7877291ce45ad1



--------------------------------

[ Upstream commit 3eb3cd5992f7a0c37edc8d05b4c38c98758d8671 ]

Commit 04d82a6d ("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 (obsolete) 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.

Introduce MAX_SHARED_LIBS_UPDATE which depends on the state of
CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET to guard the initialization of
the shared library pointer region so that it will only be initialized
if space is reserved for it.

Fixes: 04d82a6d ("binfmt_flat: allow not offsetting data start")
Co-developed-by: default avatarStefan O'Rear <sorear@fastmail.com>
Signed-off-by: default avatarStefan O'Rear <sorear@fastmail.com>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Acked-by: default avatarGreg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20240807195119.it.782-kees@kernel.org


Signed-off-by: default avatarKees Cook <kees@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent f17d1691

fs/binfmt_flat.c

+3 −1
Original line number Diff line number Diff line
@@ -72,8 +72,10 @@ 


#ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET

#define DATA_START_OFFSET_WORDS		(0)

#define MAX_SHARED_LIBS_UPDATE		(0)

#else

#define DATA_START_OFFSET_WORDS		(MAX_SHARED_LIBS)

#define MAX_SHARED_LIBS_UPDATE		(MAX_SHARED_LIBS)

#endif



struct lib_info {
@@ -880,7 +882,7 @@ static int load_flat_binary(struct linux_binprm *bprm) 
		return res;



	/* Update data segment pointers for all libraries */

	for (i = 0; i < MAX_SHARED_LIBS; i++) {

	for (i = 0; i < MAX_SHARED_LIBS_UPDATE; i++) {

		if (!libinfo.lib_list[i].loaded)

			continue;

		for (j = 0; j < MAX_SHARED_LIBS; j++) {