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glibc: fix create thread failed in unprivileged process

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Since upstream commit [d8ea0d0168 Add an internal wrapper for clone, clone2
and clone3] applied, start a unprivileged container (docker run without
--privileged), it creates a thread failed in container.

In commit d8ea0d0168, it calls __clone3 if HAVE_CLONE3_WAPPER is defined.  If
__clone3 returns -1 with ENOSYS, fall back to clone or clone2.

As known from [1], cloneXXX fails with EPERM if CLONE_NEWCGROUP,
CLONE_NEWIPC, CLONE_NEWNET, CLONE_NEWNS, CLONE_NEWPID, or CLONE_NEWUTS
was specified by an unprivileged process (process without CAP_SYS_ADMIN)

[1] https://man7.org/linux/man-pages/man2/clone3.2.html

So if __clone3 returns -1 with EPERM, fall back to clone or clone2 could
fix the issue.

(From OE-Core rev: 234a3e84640c1bb6df5fa4d3d7089a854b19d108)

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Hongxu Jia
2021-08-29 06:52:35 -07:00
committed by Richard Purdie
parent a5b257006b
commit 40305d389e
2 changed files with 80 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

79
meta/recipes-core/glibc/glibc/0001-fix-create-thread-failed-in-unprivileged-process-BZ-.patch Normal file
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@@ -0,0 +1,79 @@
From a8bc44936202692edcd82a48c07d7cf27d6ed8ee Mon Sep 17 00:00:00 2001
From: Hongxu Jia <hongxu.jia@windriver.com>
Date: Sun, 29 Aug 2021 20:49:16 +0800
Subject: [PATCH] fix create thread failed in unprivileged process [BZ #28287]
Since commit [d8ea0d0168 Add an internal wrapper for clone, clone2 and clone3]
applied, start a unprivileged container (docker run without --privileged),
it creates a thread failed in container.
In commit d8ea0d0168, it calls __clone3 if HAVE_CLONE3_WAPPER is defined. If
__clone3 returns -1 with ENOSYS, fall back to clone or clone2.
As known from [1], cloneXXX fails with EPERM if CLONE_NEWCGROUP,
CLONE_NEWIPC, CLONE_NEWNET, CLONE_NEWNS, CLONE_NEWPID, or CLONE_NEWUTS
was specified by an unprivileged process (process without CAP_SYS_ADMIN)
[1] https://man7.org/linux/man-pages/man2/clone3.2.html
So if __clone3 returns -1 with EPERM, fall back to clone or clone2 could
fix the issue. Here are the test steps:
1) Prepare test code
cat > conftest.c <<ENDOF
#include <pthread.h>
#include <stdio.h>
int check_me = 0;
void* func(void* data) {check_me = 42; printf("start thread: check_me %d\n", check_me); return &check_me;}
int main()
{
pthread_t t;
void *ret;
pthread_create (&t, 0, func, 0);
pthread_join (t, &ret);
printf("check_me %d, p %p\n", check_me, &ret);
return (check_me != 42 || ret != &check_me);
}
ENDOF
2) Compile
gcc -o conftest -pthread conftest.c
3) Start a container with glibc 2.34 installed
[skip details]
docker run -it <container-image-name> bash
4) Run conftest without this patch
$ ./conftest
check_me 0, p 0x7ffd91ccd400
5) Run conftest with this patch
$ ./conftest
start thread: check_me 42
check_me 42, p 0x7ffe253c6f20
Upstream-Status: Submitted [libc-alpha@sourceware.org]
Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
sysdeps/unix/sysv/linux/clone-internal.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sysdeps/unix/sysv/linux/clone-internal.c b/sysdeps/unix/sysv/linux/clone-internal.c
index 979f7880be..97101994e8 100644
--- a/sysdeps/unix/sysv/linux/clone-internal.c
+++ b/sysdeps/unix/sysv/linux/clone-internal.c
@@ -52,7 +52,7 @@ __clone_internal (struct clone_args *cl_args,
/* Try clone3 first. */
int saved_errno = errno;
ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
- if (ret != -1 || errno != ENOSYS)
+ if (ret != -1 || (errno != ENOSYS && errno != EPERM))
return ret;
/* NB: Restore errno since errno may be checked against non-zero
--
2.30.2

1
meta/recipes-core/glibc/glibc_2.34.bb
View File

@@ -57,6 +57,7 @@ SRC_URI = "${GLIBC_GIT_URI};branch=${SRCBRANCH};name=glibc \
file://0030-powerpc-Do-not-ask-compiler-for-finding-arch.patch \
file://0001-CVE-2021-38604.patch \
file://0002-CVE-2021-38604.patch \
file://0001-fix-create-thread-failed-in-unprivileged-process-BZ-.patch \
"
S = "${WORKDIR}/git"
B = "${WORKDIR}/build-${TARGET_SYS}"