Commit e504fc51 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Gu Bowen
Browse files

ELF: fix kernel.randomize_va_space double read 

stable inclusion
from stable-v6.1.110
commit 1f81d51141a234ad0a3874b4d185dc27a521cd27
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAU9NT
CVE: CVE-2024-46826

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1f81d51141a234ad0a3874b4d185dc27a521cd27



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

[ Upstream commit 2a97388a807b6ab5538aa8f8537b2463c6988bd2 ]

ELF loader uses "randomize_va_space" twice. It is sysctl and can change
at any moment, so 2 loads could see 2 different values in theory with
unpredictable consequences.

Issue exactly one load for consistent value across one exec.

Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Link: https://lore.kernel.org/r/3329905c-7eb8-400a-8f0a-d87cff979b5b@p183


Signed-off-by: default avatarKees Cook <kees@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Conflicts:
	fs/binfmt_elf.c
[Context conflicts.]
Signed-off-by: default avatarGu Bowen <gubowen5@huawei.com>
parent 260ccfea

fs/binfmt_elf.c

+3 −2
Original line number Diff line number Diff line
@@ -897,7 +897,8 @@ static int load_elf_binary(struct linux_binprm *bprm) 
	if (elf_read_implies_exec(loc->elf_ex, executable_stack))

		current->personality |= READ_IMPLIES_EXEC;



	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)

	const int snapshot_randomize_va_space = READ_ONCE(randomize_va_space);

	if (!(current->personality & ADDR_NO_RANDOMIZE) && snapshot_randomize_va_space)

		current->flags |= PF_RANDOMIZE;



	setup_new_exec(bprm);
@@ -1161,7 +1162,7 @@ static int load_elf_binary(struct linux_binprm *bprm) 
	current->mm->end_data = end_data;

	current->mm->start_stack = bprm->p;



	if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {

	if ((current->flags & PF_RANDOMIZE) && (snapshot_randomize_va_space > 1)) {

		/*

		 * For architectures with ELF randomization, when executing

		 * a loader directly (i.e. no interpreter listed in ELF