From cbadcad34d5907af26b1fee5049f90d169c53c9d Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Fri, 2 Jul 2021 10:49:10 +0800
Subject: [PATCH] binfmt: Move install_exec_creds after setup_new_exec to match
binfmt_elf
mainline inclusion
from mainline-v5.8-rc1
commit e7f7785449a1f459a4a3ca92f82f56fb054dd2b9
category: bugfix
bugzilla: 36868
CVE: NA
-----------------------------------------------
In 2016 Linus moved install_exec_creds immediately after
setup_new_exec, in binfmt_elf as a cleanup and as part of closing a
potential information leak.
Perform the same cleanup for the other binary formats.
Different binary formats doing the same things the same way makes exec
easier to reason about and easier to maintain.
Greg Ungerer reports:
> I tested the the whole series on non-MMU m68k and non-MMU arm
> (exercising binfmt_flat) and it all tested out with no problems,
> so for the binfmt_flat changes:
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Ref: 9f834ec18def ("binfmt_elf: switch to new creds when switching to new mm")
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
arch/x86/ia32/ia32_aout.c | 3 +--
fs/binfmt_aout.c | 2 +-
fs/binfmt_elf_fdpic.c | 2 +-
fs/binfmt_flat.c | 3 +--
4 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index 7dbbe9ffda17..8d78ea00d75f 100644
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -298,6 +298,7 @@ static int load_aout_binary(struct linux_binprm *bprm)
set_personality_ia32(false);
setup_new_exec(bprm);
+ install_exec_creds(bprm);
regs->cs = __USER32_CS;
regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
@@ -314,8 +315,6 @@ static int load_aout_binary(struct linux_binprm *bprm)
if (retval < 0)
return retval;
- install_exec_creds(bprm);
-
if (N_MAGIC(ex) == OMAGIC) {
unsigned long text_addr, map_size;
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index ca9725f18e00..af09b55d5ac5 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -244,6 +244,7 @@ static int load_aout_binary(struct linux_binprm * bprm)
set_personality(PER_LINUX);
#endif
setup_new_exec(bprm);
+ install_exec_creds(bprm);
current->mm->end_code = ex.a_text +
(current->mm->start_code = N_TXTADDR(ex));
@@ -256,7 +257,6 @@ static int load_aout_binary(struct linux_binprm * bprm)
if (retval < 0)
return retval;
- install_exec_creds(bprm);
if (N_MAGIC(ex) == OMAGIC) {
unsigned long text_addr, map_size;
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index b53bb3729ac1..60896c16f103 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -357,6 +357,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
current->personality |= READ_IMPLIES_EXEC;
setup_new_exec(bprm);
+ install_exec_creds(bprm);
set_binfmt(&elf_fdpic_format);
@@ -438,7 +439,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
current->mm->start_stack = current->mm->start_brk + stack_size;
#endif
- install_exec_creds(bprm);
if (create_elf_fdpic_tables(bprm, current->mm,
&exec_params, &interp_params) < 0)
goto error;
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index e4b59e76afb0..bbeff9385d60 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -517,6 +517,7 @@ static int load_flat_file(struct linux_binprm *bprm,
/* OK, This is the point of no return */
set_personality(PER_LINUX_32BIT);
setup_new_exec(bprm);
+ install_exec_creds(bprm);
}
/*
@@ -940,8 +941,6 @@ static int load_flat_binary(struct linux_binprm *bprm)
}
}
- install_exec_creds(bprm);
-
set_binfmt(&flat_format);
#ifdef CONFIG_MMU
--
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